

Jun.4 　　Room No.1 (Conference Room 1, 3F)

Session	[Microtremor, Surface Wave Survey, Vibration Measurement 1]
Chair	Seiji Tsuno (Tokyo Tech.)

Jun.4	10:00 - 10:20　　　 In 2022, we conducted microtremor surveys in the Higashiyama Campus of Nagoya University. We conducted a grid-array single-component microtremor survey in the front yard of the Toyoda Auditorium, whose area was approximately 60 x 60 meters, at the central campus. The grid spacing was 10 meters and 5 meters. Each measurement took 15 - 20 minutes. We used the CMP-SPAC method to obtain the phase-velocity dispersion curves. The Nagoya Municipal Subway Meijo Line runs directly underneath the arrays. We obtained anomalous dispersion curves possibly caused by the subway-related concrete structure. The S-wave velocity structure showed a high-velocity anomaly that corresponded to the location of the subway structure. We conducted the single-station three-component microtremor observation at 28 observation locations on the campus. The H/V spectra showed a similar shape to the one estimated from the S-wave velocity structure model of this area. The peak frequency of the secondary spectral peak seen at higher than 1 Hz shows good correspondence with the original microtopography and near-surface structures.	1) Microtremor survey in Nagoya University Higashiyama Campus
		*Toshiki Watanabe(1),Keiichiro Sato(2) 1:Nagoya Univ.,2:Japan Coast Guard
Jun.4	10:20 - 10:40　　　 We attempted to understand spatial changes in the subsurface structure by conducting continuous linear array microtremor observations with a sensor spacing of 5 m at the east-west measuring line (L-EW) and the north-south measuring line (L-NS) of Iwate Prefectural Athletic Park located in an urban area of Morioka City, where seismic ambient noises are expected to arrive from various azimuths. The estimated S-wave velocity is 125 m/s for the first layer at the eastern end of the L-EW survey line and 80 m/s for the first layer at the western end, indicating that the velocity is slowing from east to west. On the other hand, in the L-NS survey line, the S-wave velocity in Layer 1 was 70 m/s at both the northern and southern ends, indicating that there was little change in the subsurface structure from north to south. Comparison of the s-wave velocity structure obtained by the linear array with the pseudo S-wave velocity structure obtained by the chain array shows similar results. This result suggests the effectiveness of the exploration using linear array in the urban areas.	2) Estimation of two dimensional S-wave velocity structures in Iwate Prefectural Athletic Park by using microtremor observations with a linear array
		*Hidekazu Yamamoto・Rio Ishiduka・Tsuyoshi Saito(1) 1:Iwate University
Jun.4	10:40 - 11:00　　　 Microtremor array exploration has been widely applied for estimating shallow velocity structures in soft ground such as plains, while its application in hard ground areas such as mountainous regions has been considered difficult due to the low signal-to-noise ratio. However, the possibility of applying microtremor array exploration in hard ground areas has been suggested by using the zero-crossing method, a type of SPAC method commonly used in microtremor array exploration. This study aims to investigate the applicability of microtremor array exploration in tunnels located in hard ground areas, focusing on a mountain tunnel under construction in Kushimoto Town, Wakayama Prefecture. The dispersion curves calculated using the zero-crossing method reflected the differences in the geological layers, but the consistency with the magnitude of elastic wave velocities at each observation point was poor.	3) Microtremor Array Exploration in a Mountain Tunnel Under Construction in Kushimoto Town, Wakayama Prefecture
		*Hikaru Ota・Yugo Sato・Hiroyuki Azuma・Kosuke Kawata・Yoshiya Oda(1) 1:TMU
Jun.4	11:00 - 11:20　　　 This study discusses on a relationship between the seismic noise amplitude in the frequency range of 1-2 Hz and the river discharge in the upstream of the Shimanto River, Japan. We found a strong correlation between seismic noise amplitude of 1-2Hz and river discharge from the six meteorological events. The regression curve between the seismic noise amplitude in the 1-2 Hz and the river discharge was established using simple linear curve and it was verified by applying to another event, with the error of 6%. There is a potential to predict the trend and timing of the peak discharge appropriately. On the other hand, we also found a difficulty for the predicting small river discharge.	4) Study on Relationship between River Discharge and Seismic Noise Amplitude in the Upstream parts of Shimanto River
		*Hiroki Ichihara・Kosuke Chimoto(1) 1:Kagawa Univ.
Jun.4	11:20 - 11:40　　　 We conducted microtremor surveys in Kyowa terrace, northwestern extent of Mt. Tsukuba for estimating near-surface 3-D S-wave velocity structure with special focus on the delineation of buried bedrocks at the near surfaces. The field surveys consisted of single-point microtremor measurements to calculate H/V spectral ratio (HVSR) curves, and linear array microtremor surveys (LAMS) to derive dispersion curves. Surface topography of the surveyed area, 6 km long and 2.5 km wide, is basically flat but has a small stock of basement rocks cropping out in terrace sediments. The basement rocks are widely exposed on the northwestern flank of Mt. Tsukuba, and are inferred to be buried underneath the terrace. As a result, we could successfully delineate the buried bedrocks. Characteristic HVSR curves having peaks in the relatively high-frequency zone were identified at the northwestern flank part but also at the surrounding zone of the basement rock stock. Dispersion curves derived from LAMS data were utilized to make Vs models with aid to neural networks.	5) Mapping of buried bedrocks by microtremor surveys: A case study in Kyowa terrace, northwestern extent of Mt. Tsukuba.
		*INAZAKI TOMIO(1),KAHASHI KOICHI(2) 1:Independent,2:Kyoto Univ.


Session	[Microtremor, Surface Wave Survey, Vibration Measurement 2]
Chair	Hidekazu Yamamoto (Iwate University)

Jun. 4	13:00 - 13:20　　　 We report the results of our investigation into the applicability of 2D microtremor array measurements and surface wave method for ground investigation under the track (ballast). The investigation was conducted at two locations with different ground conditions under the track at JR East Japan Research and Development Center. The first location was a structure with ballast on a concrete floor slab, and data showing the strong influence of the concrete floor slab were obtained. As a result, both seismic array and surface wave survey showed many challenges in their application as a ground investigation method. The second location was a structure with ballast on natural ground, and good data was obtained from both methods, confirming their high applicability as a ground investigation method. In the future, experiments on actual tracks will be conducted to further confirm the challenges and applicability of these methods.	6) Assessment of the applicability of 2D microtremor array measurements and surface wave method on the Track.
		*Koji Iwamoto(1),Seisuke Kato・Yuya Kinjyo(2),Chisato Konishi・Masaya Yamauchi(1) 1:OYO ,2:East Japan Railway Company
Jun. 4	13:20 - 13:40　　　 The SPAC method extracts the SPAC coefficients by averaging the correlation between the center of the array and the circumferential points over the entire circumference, and can be obtained regardless of the direction of arrival of the microtremors. Anisotropic and linear arrays are the conditions of the exploration with respect to "propagation of microtremors. Field experiments of the SPAC method showed that the anisotropic and linear arrays did not provide any data indicating the arrival of microtremors that could be probed. In addition, the small depth of the microtremor array survey is due to the fact that the SPAC coefficients were not accurately extracted. This may be a problem in measurement or data processing.	7) Remarks on the number of observation points and depth of search for the spatial autocorrelation method
		*HISAO HAYASHI(1),Toshio TAKAGI(2),Tsuyoshi HARAGUCHI(3) 1:Geo-X Consaultant corporation,2:FUKKEN CO., Ltd,3:STORY, Ltd.
Jun. 4	13:40 - 14:00　　　 The rotational components in the horizontal plane were estimated by applying Taylor expansion to microtremor records at multiple points, and these were used to detect the phase velocity of Love waves. The detected phase velocity corresponded to the theoretical phase velocity based on nearby PS logging data. The higher the order of the Taylor expansion, the more it was possible to detect the phase velocity of the Love waves up to higher frequencies. However, the frequency band in which the Love wave phase velocity was detected is narrower than the frequency band in which the Rayleigh wave phase velocity was detected.	8) Estimation of Rotational Motions and Phase Velocities of Love Wave based on Microtremor Records
		*Yuta Soma・Hirohito Takahashi(1),Haruhiko Suzuki(2) 1:Meijo University,2:OYO Corporation
Jun. 4	14:00 - 14:20　　　 On May 5, 2023, at 14:42, an M6.5 earthquake occurred in the northeastern Noto Peninsula, and K-NET Shoin recorded JMA intensity of 6?. Ohori et al. (2023) reported on records observed at four sites in Suzu City and the results of a shaking table experiment for the high-frequency band. This report describes the results of an experiment using a shaking table owned by Nagoya University to confirm the accuracy of the low-frequency band. We confirmed that period correction factor coefficients are necessary according to the velocity and propose a method for correcting the amplitude. The proposed correction formula was applied to the observed records of the earthquake that occurred on May 5, 2023 and the 2024 Noto Peninsula earthquake that occurred on Jan 1, 2024, at 16:10, and compared with the measured seismic intensity of K-NET Shoin. The difference from the seismic intensity measured by K-NET Shoin, including other aftershock records, was about 0.06, so the amplitude could be corrected appropriately.	9) Ground Motion Records of Temporary Observation Stations in Suzu City for the Jan 1, 2024(M7.6) and May 5, 2023 (M6.5) Noto Earthquake
		*Haruhiko SUZUKI(1),Michihiro OHORI(2),Jun TOBITA(3) 1:OYO Corp.,2:University of Shiga Prefecture,3:Nagoya University
Jun. 4	14:20 - 14:40　　　 S-wave velocity profiles of shallow and deep soil layers in the damaged areas of the 2023 southeastern Turkey earthquake, such as the Kahramanmara , Antakya, and skenderun areas, were estimated through an inverse analysis of site amplification factors at strong motion stations by Yamanaka et al. (2017). S-wave velocity and thickness of each layer of a structural model of the shallow and deep soil layers over the basement with an S-wave velocity of 2.15 km/s were determined together with Q-values. Furthermore, we evaluated the contribution of the shallow and deep parts of the S-wave profiles to the ground amplification characteristics. The shallow part controls the main features of the amplification factors at the stations in the Iskenderun area. However, the effects of the deep soil layers are so large in the amplification factors at the stations in the Antakya and Kahramanmara areas.	10) Building 1D models of deep and shallow sedimentary layers in damaged areas of the 2023 southeastern Turkey earthquake
		*Hiroaki Yamanaka(1),Ozgur Özmen(2) 1:Tokyo Inst. Tech.,2:AFAD, Turkey
Jun. 4	14:40 - 15:00　　　 In this study, we examined the simulated ground motions of the aftershocks following the February 6, 2023. Kahramanmaras earthquakes using the finite difference method. Intermediate-sized events with magnitudes of Mw4.5, Mw4.6, and Mw4.9 were examined, and long-period (2 20 s) ground motion simulations were conducted in the Kahramanmaras region. The deep structure model of the southern part of Turkey was developed as a three-dimensional (3D) layered model, taking into account source regions and observation stations. The structural model was prepared by referencing previous research on the crust model of Anatolia and shallow shear wave velocity models of the Kahramanmaras basin. The synthetic waveforms calculated were compared with the recorded accelerograms provided by the Turkish Disaster and Emergency Management Presidency (AFAD) for each event. The conducted simulations of aftershocks provide valuable insights into how source parameters, source path and characteristics of the underground structure impact seismic behavior. Considering these factors, it becomes imperative to rigorously validate 3D models and wave propagation for further investigation of finite fault models. Consequently, the results derived from intermediate-level earthquakes not only contribute to predicting long-period ground motions but also enable the confident investigation of large events, incorporating intricate source characteristics, through validated structural models.	11) Simulation of Seismic Ground Motion for Aftershocks of the February 6, 2023 Kahramanmaras Earthquakes
		*Bilal Ozaslan・Hiroaki Yamanaka(1),Nobuyuki Yamada(2) 1:Tokyo Tech,2:Kochi Uni


Jun.4 　　Room No.2 (Conference Room 2, 3F)

Session	[Electromagnetic Exploration]
Chair	Hiroshi Kisanuki (OYO)

Jun.4	10:00 - 10:20　　　 The transient electromagnetic (TEM) method utilizing a superconducting quantum magnetic sensor (SQUID) was developed originally with the aim of exploring metal resources at the depth of 1000 meters. We believe that the features of SQUID-TEM method such as high resolution, high tolerance against environmental noise, and high contrast for conductivity changes contribute to carbon neutrality. Therefore, in order to apply this method to geothermal exploration and monitoring of underground carbon dioxide storage, we developed new SQUID-TEM system which enables exploration of deep underground at the depth of over 3,000 meters underground. We have applied the system to exploration of geothermal area also utilizing 3D inversion technology.	25) Development of physical exploration technology using TEM method with high-temperature superconducting quantum magnetic sensor
		*Tsunehiro Hato・Akira Tsukamoto・Keiichi Tanabe(1),Michael S. Zhdanov(2) 1:SUSTEC,2:Technoimaging LLC
Jun.4	10:20 - 10:40　　　 This study investigates the response characteristics of electromagnetic (EM) methods for a novel CO2-Enhanced Geothermal System (CO2-EGS) geothermal reservoir monitoring. Numerical simulations were conducted using a custom-developed 1D EM forward code to understand the subsurface geoelectrical changes induced by CO2 injection. The results demonstrate that changes are more pronounced in shallow，thick reservoir layers，and low-resistivity layers exhibit greater sensitivity than high-resistivity layers. For CO2-EGS applications，the geothermal reservoir is likely to exhibit high resistivity due to underground CO2 injection. Devising measurement methods tailored to capture changes in high-resistivity layers may be crucial. Furthermore，for the practical implementation of CO2-EGS，it is necessary to determine appropriate transmitter-receiver locations based on the 2D plan view of EM fields calculated by forward modeling. This study provides important insights into the applicability of EM exploration for monitoring and characterizing CO2-EGS applications.	26) Applicability of Time-Domain Grounded Wire Source Electromagnetic Exploration for Next-Generation Geothermal Power Development Utilizing Carbon Dioxide
		*Nakajima Akari・Ueda Takumi(1) 1:Waseda Univ.
Jun.4	10:40 - 11:00　　　 Time-domain electromagnetic (TDEM) methods with grounded-wire sources can control exploration depth using parameters like transmitter length and transmitter-receiver offset. However, the contribution of electromagnetic fields from grounded wires, especially the influence of grounded ends and wire shapes, requires further research. This study investigated the separation of effects from the grounded-wire transmitter's ends and wire section, focusing on the influence of wire shape, including bending, through one-dimensional forward modeling. Numerical calculations quantitatively demonstrated the impacts of the transmitter's grounded end and wire section on magnetic field responses and the influence of wire shape. These findings provide crucial information for deploying and analyzing TDEM with grounded wires in field measurements, including considerations for wire shapes. Going forward, more detailed investigations into the impact of wire shapes and their application to real data analysis will be pursued. This work contributes to understanding grounded-wire TDEM systems, which are essential for controlling exploration depth and optimizing field surveys. The insights gained can aid in developing improved TDEM methods and data interpretation techniques.	27) Evaluation of the Effect of Grounded Wire Geometry on EM Responses and Characteristics in Deep-Targeting Time Domain Electromagnetic Method
		*Shun Yamamoto・Tamaki Nishino・Takumi Ueda(1) 1:Waseda Univ.
Jun.4	11:00 - 11:20　　　 The transient electromagnetic method can be used for deep exploration, reaching depths of several kilometers. Conventional induction coil magnetometers measure the time derivative of the magnetic field, generating electromotive force. In contrast, magnetometers like SQUID can directly measure the mag netic field, allowing for greater exploration depths. However, more research is needed to analyze the responses of the horizontal magnetic field components, as sign reversals can occur under certain conditions. Therefore, this study focuses on the horizontal component responses of the magnetic field, using grounded wire and loop sources as transmitters and SQUID magnetometers as receivers. The magnetic field responses were converted to apparent resistivity by applying the homogeneous difference transformation algorithm, and their applicability was carefully examined.	28) Apparent resistivity transformation and RCG inversion for horizontal component magnetic field of TDEM response
		*Shintaro Yuki・Genki Nakamura・Takumi Ueda(1) 1:Waseda University
Jun.4	11:20 - 11:40　　　 In this study, we performed a deep learning inversion of time-domain airborne electromagnetic survey data for geothermal resource exploration using the HeliTEM system by the Japan Organization for Metals and Energy Security (JOGMEC). Deep learning inversion of electromagnetic survey data is advantageous in that it does not require an initial model estimation and can analyze a large amount of observation data at high speed. Specifically, deep learning inverse analysis was performed on data from the Hachimantai and Kuju areas, and the results were compared with those obtained by JOGMEC's optimization method using the derivative of the objective function. The results were evaluated in terms of residuals (RMSPE) and vertical and horizontal slices of geoelectrical structures. In both the Hachimantai and Kuju areas, the deep learning and JOGMEC inversion results showed harmonic resis- tivity structures at the surface to depth of investigation. Since deep learning significantly reduces the computation time, it is expected to be effectively used for inversion of wide-area and large-scale data such as airborne electro- magnetic surveys.	29) Layered Earth Inversion of Time Domain Airborne Electromagnetic Data in Geothermal Areas Using Deep Learning
		*Kengo Nakanishi・Tamaki Nishino・Takumi Ueda(1) 1:Waseda Univ.


Session	[DAS (Distributed Acoustic Sensing)][VSP, Borehole Seismic]
Chair	Kosuke Chimoto (Kagawa Univ.)

Jun. 4	13:00 - 13:20　　　 The Kyushu Electric Power Co (KEP) owns the Hatchobaru and the Otake Geothermal Power Plants. We used the optical fiber installed in the H-26 geothermal borehole in the Hatchobaru Geothermal Power Plant down to a depth of 1,600 m. A medium-sized seismic vibrator was operated at twelve locations surrounding the H-26 borehole. We also used surface seismometers near the borehole. We obtained the Vp structure using the first arrivals of the distributed acoustic sensing (DAS) and surface seismometer records and computed the twelve synthetic DAS records. We migrated the reflection arrivals using the Vp structure obtained in this study. The seismic reflections focused around 2.0 2.5 km. They are probably the basement rock zone filled with fluid. Forty microearthquakes were observed during two weeks. We determined the hypocenters in 3D grid search method minimizing O-C. The hypocenters were distributed between the Hatchobaru and the Otake Geothermal Power Plants at a 2.2 4.0 km depth, and the depth and spatial distributions suggest the microearthquakes were the ordinary volcano-seismic activity in the Kuju volcanic area.	30) Seismic exploration at Hatchobaru-Otake geothermal field, Kyushu.
		*Junzo Kasahara(1),Yoko Hasada(2),Hitoshi Mikada(3),Hiroshi Ohnuma(1),Yoshihiro Fujise(4) 1:ENAA,2:Daiwa Exploration and Cosulting Co. Ltd.,3:Kyoto Univ.,4:WELMA
Jun. 4	13:20 - 13:40　　　 In order to establish a new method for detecting fracture systems near wells in geothermal areas, we conducted a DAS-VSP field test using multiple wells and confirmed the effectiveness of an active seismic source. As a result, we have shown that the active seismic source can be used to visualize the fracture structure by diffraction imaging. We found that AE observed during vibrator sweep operations could also be useful for diffraction imaging. The use of multiple wells and the combined use of active and passive seismic sources were proven to be effective in expanding the image area and improving the fault image.	31) Fracture system exploration with active and passive DAS-VSP using Multi-Well
		*Moeto Fujisawa・Naoshi Aoki(1),Takuro Kanetsuki(2) 1:JGI,2:JOGMEC
Jun. 4	13:40 - 14:00　　　 MH21-S is investigating the applicability of DAS (Distributed Acoustic Sensing) using optical fibers installed on the sea floor for geophysical monitoring. While DAS has been applied to VSP (Vertical Seismic Profile) surveys, where data is acquired with cables in the wellbore, there are still a few examples of seismic reflection surveys with cables on the surface. In addition, the development of optical fiber cables that strongly generate backscattered waves and HWC （Helical Wounded Cable） that arranges optical fibers helically within the cable is progressing, and the sensitivity of sensors has greatly improved. In this presentation, we will report on the capability evaluation of DAS and the status of consideration for three-component data acquisition at Aquistore CCS site in Canada.	32) Data acquisition for DAS capability evaluation at Aquistore CCS site in Canada
		*Toshiaki Kobayashi・Naoyuki Shimoda・Hiroaki Tanaka・Hidehiko Shimizu(1),Zeinab Movahedzadeh(2),Don White(3),Michael Mondanos・Anna Stork(4) 1:JOGMEC,2:PTRC,3:GSC,4:Silixa
Jun. 4	14:00 - 14:20　　　 DAS-VSP is widely applied as an efficient method to monitor injected CO2 behavior in CCS. To further improve its cost-benefit for future CCS monitoring, we conducted two types of field experiment in our field. Firstly, we conducted simultaneous shooting experiments using the phase encoding approach. As DAS-VSP is acquired in a quiet environment, the approach is effective and even expected to improve SNR as harmonic noise can be canceled, which is usually not the case for surface seismic acquisition. Second, we conducted a multi-well DAS-VSP acquisition experiment in which DAS were installed in two wells simultaneously. Although the imaging area expanded as expected, the result revealed the difficulty of handling precise amplitude information of DAS data.	33) Experimental study of simultaneous DAS-VSP acquisition toward cost-effective CCS monitoring
		*Takao Nibe・Takuya Miura・So Sugawara(1),Masafumi Katou・Yuki Imai(2),Takeya Nagata(3) 1:JAPEX,2:JGI,3:GSC
Jun. 4	14:20 - 14:40　　　 Seismic exploration is one of the geophysical survey methods to estimate the subsurface velocity distribution from the recording of artificial seismic waves. Recently, it has been applied to various areas, e.g., geothermal surveys and CCS monitoring as well as oil and gas exploration, civil engineering, and ground investigation. A particularly promising technique within seismic exploration is Full Waveform Inversion (FWI), which is expected to achieve high-resolution results by utilizing full waveform records. FWI is usually defined as a problem of minimizing a cost function, the sum of squares of residuals between observed and calculated waveforms. The velocity model is then updated by computing the gradients of the cost function with respect to the model. Alternatively, the problem can also be viewed as minimizing the cost function for each source point or shot.In this study, we formulate this model-updating method using adjoint equations and Newton's method, and we implement it using Julia programming language. We also numerically evaluate the difference in resolution and convergence speed of FWI results between using a scalar cost function and a vector cost function.	34) Development of time-domain FWI code using Julia for minimizing a vector cost function and noise influence evaluation
		*Kento Kamimura(1),Shohei Minato・Toshiyuki Yokota(2),Takumi Ueda(1) 1:Waseda Univ.,2:AIST
Jun. 4	14:40 - 15:00　　　 To evaluate the performance of ground vibration measurement using DAS technologies, we buried optical fiber cables in a test site in Tsukuba City, Ibaraki Prefecture, and measured microtremors including vibrations caused by vehicle or random walking. The vehicle vibrations were generated by driving a regular passenger car twice a minute on a test course located roughly parallel to the cables and about 7.5m away from it. The walking vibrations were generated by having multiple people walk randomly within 1m of the cables in a section of about 50m. We performed microtremor linear array analysis using the CMP-SPAC method on the DAS records to obtain frequency-phase velocity images. The phase velocity image obtained from the records of microtremors that included vehicle or random walking vibrations was able to extract high-frequency phase velocity compared to that obtained from the records of ambient noises without them. These results indicate that including vehicle or random walking vibrations can contribute to estimating the shallow S-wave velocity structure in the measurements of microtremors using DAS.	35) Microtremor linear array measurement using DAS records including random walking and traffic vibrations.
		*Naoto Ogawa・Haruhiko Suzuki・Ken Sakurai・Chisato Konishi(1),Hiroyuki Fujiwara・Hiromitsu Nakamura・Shohei Naito(2) 1:OYO Corp.,2:NIED


Jun.4 　　Core Time：Room No1 (3F)

Session	[Poster]
Chair	Takao Nibe (JAPEX)

Jun. 4	15:20 - 17:20　　　 AMT method exploration is an exploration technique for shallow subsurface structures that uses relatively high-frequency electromagnetic field fluctuations. When analyzing AMT data in geothermal areas, the target areas are often located in mountainous regions and are easily affected by the topography in data analysis. The 3-D inversion program FEMTIC can generate a tetrahedral mesh and consider topographic effects using the finite element method.Furthermore, the use of parallel computation enables relatively fast computation. In this study, we analyzed the resistivity structure using AMT data obtained in a geothermal area. We compared it with previous 2-D analyses, geological maps, and well-logging data to clarify the topographic effects on the inversion results. The comparison results with and without topography showed that a more accurate estimation of resistivity distribution is possible when topography is considered.	P-1) Effectiveness evaluation of 3-D inversion of AMT data considering topography
		*Yuta Mori・Toshiaki Tanaka・Hideki Mizunaga・Koji Hashimoto(1) 1:Kyushu University
Jun. 4	15:20 - 17:20　　　 This study utilized remote sensing satellite imagery and aircraft geophysics to map the geology and mineral exploration potential of the Francistown region, located southwest of the Zimbabwe craton in Botswana. ASTER Level-1B daytime Thermal Infrared (TIR) and aeromagnetic data were employed. The region comprises various rock types, including felsic, mafic-ultramafic, and gneiss, with significant mineralization potential. Remote sensing techniques successfully delineated major rock formations and identified mineral-rich areas. The aeromagnetic data analysis aided in identifying structural features. The study employed the Center for Exploration Target (CET) grid analysis system and Porphyry Analysis technique to map potential mineralization sites aligned with known mineral deposits in the area. The combination of remote sensing and aeromagnetic methods proved effective and cost-efficient, demonstrating potential for application in other mineral-rich regions.	P-2) Integrated use of ASTER TIR and aeromagnetic data to geological mapping and subsequent mineral exploration in Francistown region, Northeast Republic of Botswana
		*Pabalelo Sono(1),Ame Thato Selepeng(2),Hideki Mizunaka(1),Felicia Akinyemi(3) 1:Kyushu Univ.2:Botswana International Univ.3:Univ. of Bern,
Jun. 4	15:20 - 17:20　　　 This study investigates the automatic velocity analysis of seismic reflection data using semblance panels through Convolutional Neural Network (CNN). Three different label arrangements for velocity profiles are explored to examine their influence on the model's accuracy. To create a CNN model for the automatic velocity analysis, 500 synthetic CMP gathers were generated and processed three different label arrangements. Modified AlexNet was used for the DL model architecture.The results indicate that the model trained with a 2 x 20 2D aligned label arrangement achieves the highest accuracy in all visual, numerical, and processing evaluations on a random training data.However, all three models suffer from a lack of generalizability, performing poorly on untrained test data. To improve the accuracy of the network, future work will focus on increasing the training data volume and employing the use of continuous labels.	P-3) Automatizing Velocity Analysis of Seismic Reflection Data Using Convolution Neural Network
		*Sungyong Lee・Toshiki Watanabe(1) 1:Nagoya Univ.
Jun. 4	15:20 - 17:20　　　 We conducted S and P wave seismic reflection surveys at Ama area in Minamiawaji City, Hyogo Prefecture, to clarify the spatial distribution and the deformation structure of the Minato-Honjo Fault located in the southwest of Awaji Island. Seismic depth sections show reflectors at depths shallower than an elevation of about -80 m and -120 m in S and P wave survey, respectively. Reflectors of both S and P wave survey are found at depths consistent with the boundaries identified in the geological column. The depth cross section of P waves survey shows that the top of the basement rock becomes shallower toward the west of the survey line. Several structures that represent the deformation of the Minato-Honjo Fault are observed on the east side of the survey line. On the other hand, the depth profile of S waves survey shows that the top of the basement rock (Izumi Group) becomes shallower toward the middle of the survey line. We will conduct further analyses to improve the cross-section and discuss the deformation structure of the Minato-Honjo Fault.	P-4) Shallow Subsurface Structure in the Ama area, Minami-Awaji City, Hyogo Prefecture
		*Sawako Kinoshita・Shinobu Ito(1) 1:AIST
Jun. 4	15:20 - 17:20　　　 The use of renewable energy is essential to achieve carbon neutrality by 2050, and many large wind farms are in operation in Japan and abroad in locations with good wind conditions. Wind turbines are constantly exposed to strong winds, and the high struts and large wind turbines cause microtremors. Wind turbines are expected to be a source of microtremors for exploration because they operate day and night throughout the year, they are often installed in coastal areas, and the waves coming in on the shore are also significant. In this report, as an initial study of microtremor sources, microtremor meter observations were made at a distance of 21 km from the vicinity of a large wind turbine along the coast. Microtremors of 1.2-40 Hz caused by wind turbines and 0.2-1.5 Hz caused by waves were observed in the vicinity of the wind farm. These microtremors were detected up to a distance of 1.5 km from the wind turbines.	P-5) Initial study of microtremor observation using wind turbines along the coast
		*Yoshinori Sanada・Shuntaro Miyanaga(1) 1:Taisei Corporation
Jun. 4	15:20 - 17:20　　　 The sparse estimation method using the L1 norm as the regularization term, represented by lasso, has attracted attention as an alternative optimization method to the constrained least squares method using the L2 norm as the regularization term. Various extensions to the lasso have been proposed, and one of them, the fused lasso, was applied to a one-dimensional inversion of surface wave apparent phase velocity data. It is a nonlinear generalized lasso problem, and the alternating direction method of multipliers (ADMM) is used as the solution algorithm. The extended Bayesian information criterion (EBIC) was employed to select the hyperparameters, i.e., the optimal model. The method was applied to several numerical examples, and its effectiveness was confirmed.	P-6) Inversion of surface wave apparent phase velocity data using fused lasso
		*Shigeki Kawamura(1) 1:unaffiliated
Jun. 4	15:20 - 17:20　　　 The water injection experiment has been conducted to stabilize steam production in the Okuaizu geothermal field. We had maintained continuous monitoring microseismic events (MS) using nine seismic stations in this field and indirectly capture fluid flow activity within the geothermal reservoir. We present the results of MS monitoring from May 2015 to February 2024 and investigate the correlation between water injection and the observed MS trends. The MS events (32,829 events in total) were observed and the spatial distribution of MS was classified into two main areas; the South region of the injection well and the Northeast region of the injection well (i.e. near the Sarukurasawa fault). By comparing the characteristics of MS occurrence between these two areas during a series of water injection experiments, the several insights emerge: (1) in the South region of the injection well, the increase/decrease in the number of MS events tend to align with variations in the water injection rate, (2) in the Northeast region of the injection well, minimal correlation is discernible between the number of MS events and the injection rate of water. In summary, our finding suggests disparate conditions governing the activation of MS between these two delineated regions.	P-7) The temporal variation of microseismic events between water injection experiment in Okuaizu geothermal field
		*Naoki Aoyagi・Kyosuke Okamoto・Takuya Ishibashi・Eiji Kuwana・Yuki Tanaka・Yusuke Yamaya・Hiroshi Asanuma(1),Takashi Okabe(2),Tetsuo Nakagawa(3),Takuya Teraoka(4) 1:AIST,2:GERD,3:OAG,4:JOGMEC


Jun.5 　　Room No.1 (Conference Room 1, 3F)

Session	[Microtremor, Surface Wave Survey, Vibration Measurement 3][Microseismic]
Chair	Jun Matsushima (Univ. of Tokyo, GSFS)

Jun. 5	9:30 - 9:50　　　 This study shows S-wave tomography can be performed on road embankments by using vibration excitation by a sledge hammer on the slope surface to intercept the investigation area. S-wave vibration records which are useful for seismic evaluation of embankments can be obtained without traffic control on the main road. S-wave velocities in the lower area under the main road are difficult to obtain not only by boring and penetration tests, but also by other geophysical surveys such as PS logging, surface wave surveys, and microtremor arrays, therefore will be a valuable exploration method. Tomographic exploration of the high embankment behind the abutment proved to be a highly applicable exploration target because of the relatively high amplitude of the refracted waves relative to the surface wave noise of traffic vibration. It is often difficult to cross a wired trigger cable on a main road without traffic control, but the use of a wireless transmission system allows tomographic surveys to be conducted without signal line communication. It is hoped that this study will increase the number of options for geophysical exploration methods that adapts the needs of surveys and increase the opportunities for the use of geophysical surveys.	12) S-wave tomography surveys across a road for seismic evaluation of high embankments
		*Kyosuke Onishi・Yusuke Oishi・Nozomu Suzuki・Takuo Azuma・Shunji Kato(1) 1:PWRI
Jun. 5	9:50 - 10:10　　　 In recent years, methods using surface waves have been applied to efficiently estimate the depth of surface cracks on the surface of concrete structures, and estimation formulas have been proposed. Previous studies have focused on surface waves incident perpendicular to the surface cracks, but oblique incident surface waves have not been sufficiently investigated. If the surface crack depth could be estimated even in the oblique case, it would improve the efficiency of inspections. Therefore, in this study, we aim to investigate whether it is possible to estimate the depth of surface cracks even when surface waves are incident obliquely on them. To achieve this, we conducted experiments using a concrete specimen with grooves that mimic cracks, where surface waves were inducted by impacting with steel balls and measured the amplitudes before and after passing through the surface cracks. The results showed that the estimation error in the oblique case is relatively small, about 40%, suggesting that it is possible to estimate the surface crack depth using surface wave attenuation even in the case of oblique incidence.	13) Estimation of concrete crack depth using surface waves in a laboratory test
		*Nahoko Akiyoshi・Hiroyuki Azuma・Kentaro Ohno・Yoshiya Oda(1) 1:TMU
Jun. 5	10:10 - 10:30　　　 We compute receiver function and autocorrelation function of strong motion records induced by local earthquakes occured around Kanto region. The strong motion over 500 stations were observed by SK-net which is the strong motion observation network deployed in the Kanto region. For the receiver function and autocorrelation function, we picked P-wave part from the theoretical travel time and automatically computed the functions of P-wave part. The receiver function and autocorrelation function clearly showed the Ps and PpPs phases with P-wave reflected waves in the functions. The Ps-P times from receiver function in the Kanto basin were well estimated because it corresponds well to the sedimentary structure model of the Kanto basin. We computed H-V stack at a station in Yachiyo City, Chiba Prefecture to verify the J-SHIS velocity structure model. The H-V stack well estimated the P-wave and S-wave velocities as well as the depth the bedrock.	14) Estimation of elastic wave velocity structure models of the Kanto basin using receiver function and autocorrelation function applied to local earthquake records
		*Kosuke Chimoto(1) 1:Kagawa Univ.
Jun. 5	10:30 - 10:50　　　 We had continuously measured near-surface shear wave velocity (Vs) using seismic ambient noise for two months in terms of microtremor array measurements in South San Fransico Bay Area, CA, U.S. We installed 24 geophones in a triangular array of 8 m side, continuously recorded ambient noise, processed data in real-time using cloud server, and summarized phase velocity and Vs changes associated with rainfall. There was a considerable amount of rainfall from January to February in 2024. Total rainfall was approximately 225 mm in that period. Phase velocities in the frequency ranges, 20~30 Hz and 30~40 Hz significantly decreased from 350 to 200 m/sec and from 300 to 110 m/sec respectively in that period. We applied non-linear inversion to the several dispersion curves between Jan. 21st and Feb. 10th and estimated Vs profiles to 10 m deep. Resultant Vs profiles show that Vs from surface to 6 m deep decreased 10~40 %. The Vs particularly decreased about 40 % at 1~2 m deep from 210 to 130 m/sec. It should be noted that the higher frequency range decreased earlier and lower frequency ranges decreased later. Different change periods might imply water penetration process from shallow to deep.	15) S-wave velocity changes associated with rainfall observed by continuous seismic ambient noise measurements
		*Koichi Hayashi(1) 1:Kyoto University
Jun. 5	10:50 - 11:10　　　 Our studies have focused on the possibility that the inverse dispersion results of phase velocities of Rayleigh waves with higher order modes observed in microtremor array exploration can identify structures that were not captured in one-dimensional surveys. To examine the possibility, we conducted seismic and microtremor observations for 1.5 months near Hishikari Mine for the application to the seismic interferometry method. We report the autocorrelation and cross-correlation functions obtained from the observation results.	16) The application of seismic interferometry on ground motion and microtremor observation records in the Hishikari area
		*Masahiro Ono・Yuichiro Minami・Shunsuke Nogami(1),Hiroaki Yamanaka(2),Yoshinori Okaue(3) 1:SRED,2:Tokyo Inst. Tech.,3:SMM
Jun. 5	11:10 - 11:30　　　 A water recharge test has been conducted by JOGMEC in the Okuaizu geothermal field (Fukushima, Japan) since 2015 to stabilize steam production. As part of the test, the monitoring of subsurface fluid flows using microseismic monitoring has also been carried out. In this study, we performed a time series of seismic wave travel time tomography and attenuation tomography using microseismic data from 2017 to 2018 (prior to the start of the continuous water recharge test in operation) and after 2022 (during the continuous water recharge test). As a result, we identified a region near the recharge well that exhibited increased seismic velocity and decreased attenuation strength in line with the recharge test. In this study, we report the possibility of estimating reservoir behavior in response to water recharge by analyzing variations in seismic velocity and attenuation structures, as discussed above. More precise insights into reservoir behavior, such as fluid flow paths and the phase of pore water, can be gained by utilizing information on microseismic distribution, Vp/Vs, and other parameters.	17) Estimation of seismic velocity and attenuation structure based on the Double-Difference method: application to an injection test conducted in the Okuaizu geothermal field, Fukushima, Japan
		*Kyosuke Okamoto・Naoki Aoyagi(1),Yusuke Mukuhira・Dian Darisma(2),Hiroshi Asanuma(1) 1:AIST,2:Tohoku University


Session	Executive Sessions
Chair	Jun Matsushima (Univ. of Tokyo, GSFS)

Jun.5	15:00～16:00	Yasushi Taguchi (NIED）

Jun.5	16:00～17:00	Toshihiro Uchida (AIST)



Jun.5 　　Room No.2 (Conference Room 2, 3F)

Session	[Integrated Geophysical Survey][Others]
Chair	Koji Iwamoto (OYO)

Jun. 5	9:30 - 9:50　　　 In this study, as an initial step in the development of a virtual seismic observation network for estimating seismic motions at locations where there are no seismic stations, we conducted P-wave travel time prediction and maximum amplitude prediction using deep learning. We generated seismic data by using numerical simulations for three cases of reference point arrangements. As a result, we were able to predict the P-wave travel time with a certain degree of accuracy. However, the accuracy of the prediction of the maximum amplitude varied depending on the earthquake used for the prediction.	36) A basic study on numerical experiments using deep learning for the construction of virtual seismic networks
		*Koki Tanimura・Hiroyuki Azuma(1),Toshiki Watanabe(2),Kazuya Shiraishi(3),Yoshiya Oda(1) 1:Tokyo Metropolitan Univ.,2:Nagoya Univ.,3:JAMSTEC
Jun. 5	9:50 - 10:10　　　 The shallow methane hydrate (MH) refers to MH that is present from the seafloor to a depth of approximately 100 m below the seafloor. In the area off-Tango Peninsula, the occurrence of the shallow MH has been suggested on and below mounds on a ridge that extends into the Oki Trough. Many pockmarks without mounds are distributed around there. The subseafloor structures below the pockmarks revealed the followings: (1) Layers show good continuous below and around the pockmarks, (2) layers below the pockmarks show thickness variation compared to surrounding layers, and (3) bottoms of the pockmarks appear to be nearly aligned on certain layers. We developed a model that accounts for the dynamic loss of intermittent massive MHs. We found that various thicknesses of layers just below the pockmarks may have been formed by the loss of massive MHs on and below the seafloor.	37) Possible loss of massive methane hydrate beneath the seafloor inferred from the sub-seafloor structure below the pockmarks
		*Miho Asada・Ayumu Miyakawa(1) 1:AIST
Jun. 5	10:10 - 10:30　　　 While drone-borne magnetic and electromagnetic surveys have been increasing recently, few have been applied for ore deposit exploration. In a drone electromagnetic survey (D-GREATEM) that we conducted for detailed investigation of the Hishikari Gold Mine, the acquired data were mixed with electromagnetic noise from the Ebino VLF transmitter and the mine facilities, resulting in degraded signal-to-noise ratio. To reduce influence of the noise for better accuracy, we time-integrated the transient responses acquired by coils and set both the signal intensity and shapes of the responses as unknowns in the inversion analysis. With those measures implemented, the analysis results generally agreed with the resistivity distribution obtained in the past surveys in the survey area, indicating applicability of the D-GREATEM method even in noisy areas. We also ascertained that the method can be used for determining the extent of alteration zones around shallow hydrothermal deposits.	38) Case study of drone electromagnetic survey in high-noise region
		*Shunsuke Nogami・Kuo-Hsuan Tseng・Yoshio Nakasato(1),Yoshinori Okaue(2),Akira Jomori(3) 1:SRED,2:SMM,3:NeoScience
Jun. 5	10:30 - 10:50　　　 Cost-effective geothermal development requires an increase in the success rate of well drilling. To achieve this, reservoir locations must be estimated more accurately and efficiently than in the past. Case studies of major geothermal areas in Japan have shown that the geological structure and geothermal system structure are different. The reason for this is that geological structures formed by layered volcanic products and geothermal systems formed by hydrothermal alteration are different in origin. However, the processes of reservoir formation associated with faulting are common, so potential exploration methods and seismic surveys are effective. Electromagnetic surveys are most important for evaluating the formation of geothermal systems because the components of geothermal systems are strongly correlated with resistivity. It is essential to combine these multi-physics exploration methods appropriately from regional to detailed surveys. Developing a method for electromagnetic exploration to detect reservoirs below caprock is a future challenge.	39) The Role of Geophysical Techniques in Geothermal Exploration
		*Hideaki Ban・Toshiaki Tanaka・Hideki Mizunaga(1) 1:Kyushu University
Jun. 5	10:50 - 11:10　　　 This study examined the effectiveness of a physics-informed machine learning to estimate temperature, pressure and permeability distributions at geothermal fields based on well logs and magnetotelluric responses. We used a deep neural network for the estimation, and mass and energy conservation laws of hydrothermal fluid were taken into consideration. The numerical model of the Kakkonda geothermal field was used for the examination. Our results showed that the estimation accuracies of temperatures and pressures were improved by considering physics laws and boundary conditions in the deep neural network. The incorporation of magnetotelluric responses was particularly effective to delineate permeability structure at depths.	40) Development of a method for estimating geothermal structures using physics-informed machine learning and evaluation with numerical models for hydrothermal systems
		*Kazuya Ishitsuka(1),Keiichi Ishizu(2),Yusuke Yamaya・Norihiro Watanabe(3),Anna Suzuki(4),Yusuke Ohta(5),Mitsuru Utsugi(1),Yosuke Kobayashi(6),Toru Mogi(7),Hiroshi Asanuma(3), et al. 1:Kyoto Univ.,2:Hyogo Univ.,3:AIST,4:Tohoku Univ.,5:JAMSTEC,6:Muroran Tech. Univ.,7:Nagoya Univ.


Jun.6 　　Room No.1 (Conference Room 1, 3F)

Session	[Reflection Seismic Survey]
Chair	Miho Asada (AIST)

Jun. 6	9:30 - 9:50　　　 Challenges of applying AI and deep learning to seismic sections typically involve CNNs, and improving their accuracy is a major topic. Transformer models, which have demonstrated high accuracy in the field of NLP (natural language processing), are also becoming mainstream in image recognition and object detection. In this study, object detection was performed using the hierarchical Transformer models SegFormer and its enhanced version, U-Segformer. The objective of object detection was to identify amplitude anomalies observed before and after CO2 injection. We evaluated the effectiveness of the application using publicly available data from Sleipner. This paper reports on the methodology used and the prediction results obtained from the analysis of public data.	18) Application of Objective Detection to Seismic data using Transformer model (Regarding changes before and after CO2 Injection data)
		*Hironori Sakaguchi・Jun Matsushima(1) 1:Univ. of Tokyo, GSFS
Jun. 6	9:50 - 10:10　　　 Application of semantic segmentation to real geophysical survey data has been actively application and discussed. Sakaguchi et al. (2022)1, the possibility of application to automated BSR detection for reflection seismic data was discussed. Subsequently, Sakaguchi et al. (2022)2 discussed its application to BSR detection for data presenting complex geological structures in the 3D seismic processing data. However, the results were obtained using a CNN (Convolutional Neural Network) model, and to further promote practical utilization, it was necessary to improve accuracy and reduce calculation cost. Therefore, object detection (Semantic segmentation) was performed using the SegFormer based on the Transformer model. We applied it to real reflection seismic data and discuss the Training flow, prediction BSR, and their accuracy.	19) Application of semantic segmentation for real 3D seismic data.
		*Hironori Sakaguchi・Kazuyoshi Takaichi・Satoshi Kodama・Yusuke Shimono・Aoi Kamata(1),Shohei Ishinabe・Akira Ebitani(2) 1:CTC,2:JOGMEC
Jun. 6	10:10 - 10:30　　　 Recent advances in various seismic attenuation measurement methods, such as sonic logging and walkaway vertical seismic profiling (w-VSP) allow the measurement of S-wave attenuation over a broadband frequency range in methane hydrate-bearing sediments (MHBS). To elucidate the mechanisms responsible for the S-wave attenuation values measured from w-VSP and sonic dipole data in the MHBS at the Nankai Trough in Japan, we applied three types of Biot extension models to demonstrate the theoretical possibility of the frequency dependence of P-wave attenuation in the same field. However, these rock physics models underestimate the magnitude of S-wave attenuation. To fill the gap between the observed and theoretical S-wave attenuation values, we formulated a rock physics model that integrates dynamic friction on the contact lines as a contributing mechanism for S-wave attenuation. We demonstrated significant S-wave attenuation by considering the dynamic friction on the contact line, which implies that the contact line dynamic friction between a liquid-like hydrate layer and sand grains is a possible mechanism for S-wave attenuation.	20) Rock physics study on S-wave attenuation in methane hydrate-bearing sediments at Nankai Trough: Contact line friction
		Zihan Niu(1),Linsen Zhan(2),*Jun Matsushima(1) 1:Univ. of Tokyo, GSFS,2:Peking Univ.
Jun. 6	10:30 - 10:50　　　 This study delves into the striking parallels between bat echolocation signals and seismic exploration methods, providing a unique lens on signal processing through the principles of information theory. By meticulously examining the adaptive features of bat signals across various echolocation phases, the study uncovers the bats' sophisticated strategies in modifying time duration and frequency sweeps to efficiently navigate different environments. These natural acoustic adaptations are then insightfully applied to the design of seismic signals, promoting a versatile, context-aware approach inspired by bats. The research integrates spectral analysis, entropy calculations in both frequency and time domains, and a comparative study with simulated signals ranging from constant frequency to linear and nonlinear sweeps. This comprehensive analysis demonstrates the intricate balance bats maintain between signal stability and adaptability for effective echolocation. Consequently, this study not only advances our understanding of bat echolocation mechanisms but also offers practical insights into optimizing seismic signal selection based on specific exploration objectives, especially highlighting the potential roles of constant frequency signals in seismic surveys. This work stands as a testament to the potential of biomimicry in enhancing technological approaches in seismic exploration.	21) Revisiting Vibroseis Sweep Signals from the Viewpoint of Information Entropy: Implications from Bat Echolocation
		Wangjie Xu・*Jun Matsushima(1) 1:Univ. of Tokyo, GSFS
Jun. 6	10:50 - 11:10　　　 The vertical resolution in seismic data used for interpretation work is determined by data acquisition specifications and processing costs. Higher resolution is desired from interpreters to illustrate the geological structures in a fine scale. The resolution enhancement method is applied to achieve higher resolution data by up-sampling and to optimize bandwidth using both high- and low- resolution data. For example, many enhancement methods use high-resolution synthetic data and deep learning algorithms for optimization. We present a resolution enhancement model built by a) low-resolution seismic data as input, and b) high-resolution seismic data, from a limited area, as supervised data without using synthetic data. The model is applied not only to the training area but also to the testing area for verification.	22) Application of Deep Learning Model for Resolution Enhancement of Offshore Seismic Data
		*Akira Ebitani・Shohei Ishinabe・Yusaku Konishi・Toshihiro Ike(1) 1:JOGMEC
Jun. 6	11:10 - 11:30　　　 We have been continuously conducting dense seismic surveys to investigate the subsurface geological structure and seismic wave velocity distribution in the seismogenic zone. Multi-channel seismic reflection surveys with dense survey line layout in a wide-area are conducted to reveal detailed geological structures such as the topography of the oceanic crust, fault distribution and deformation structures in the crust by utilizing both the new and legacy data. On the other hand, wide-angle reflection surveys using ocean-bottom seismographs have enabled us to estimate detailed seismic velocity structures through inversion analysis of traveltimes and waveforms. We have also developed imaging techniques using reflection waves in the wide-angle seismic data. Furthermore, an integrated analysis, applying pre-stack depth migration to the multi-channel seismic data based on the accurate velocity model derived from the wide-angle seismic data, provides reliable results with improved quality of the seismic reflection profiles that are consistent with both datasets.	23) Crustal structure imaging by marine multichannel reflection and ocean-bottom wide-angle reflection surveys
		*Kazuya Shiraishi・Ryuta Arai・Tetsuo No・Yasuyuki Nakamura・Gou Fujie(1) 1:JAMSTEC
Jun. 6	11:30 - 11:50　　　 We are developing a new seismic wave processing system, which is executing on Unix operating system. We can use this system by the similar operation as Seismic Un*x (hear after SU). This system can import more kind of seismic formats data than SU. These are not only SEGY but also SU, seg2, ORG, and binary (unix type and fortran sequential type). Regarding for parameters definition, trace displaying, and data picking, this system is more flexible than SU. Therefore, this system can be applied for the data processing of the small size of 2dimensional commercial seismic exploration like as for civil engineering and for geo-science	24) SU like command-based system for Seismic wave processing
		*Makoto Okada (1) 1:NC Geophysical survey


Jun.6 　　Room No.2 (Conference Room 2, 3F)

Session	[Electrical Exploration][Ground Penetrating Radar]
Chair	Kyosuke Onishi (PWRI)

Jun. 6	9:30 - 9:50　　　 In order to avoid red tide damage, the option of using "Saline Groundwater" for aquaculture on land is being considered. To examine aquaculture on land, the potential survey of seawater intrusion in coastal aquifer of Nemuro Peninsula, Hokkaido prefecture, Japan was investigated using an Electric Resistivity Tomography (ERT). the IRIS instrument of Syscal Pro with 48-72 ch was used for ERT and installed eleven survey lines at the site and digital data were collected by dipole-dipole, Wenner-Schlumberger and Wenner electrode arrays. The data were inverted with the software RES2DINV and RES3DINV and obtained subsurface resistivity models. The model revealed that a low resistivity zone of less than 10 Ωm was detected at depths more than 12 m on the survey line located on the east side of Hanasaki Port. This low resistivity zone possibly indicates seawater intrusion from the sand layer to nemuro formation based on reference of the borehole data. In particular, the Nemuro Formation, which has increased pore space due to weathering, was estimated to have a high potential for seawater intrusion.	41) An assesment of sea water intrusion into costal aquifer by ERT at the Nemuro peninsula, Hokkaido, Japan
		*Riho Takahashi(1),Junya Maruyama・Tsuyoshi Shintani(2),Ryouji Kudo・Yuya Ishii(3),Shin'ya Sakanaka(1) 1:Akita Univ,2:Hokkaido Research Organization,3:Nemuro-City Fisheries Research Institute
Jun. 6	9:50 - 10:10　　　 A time-lapse resistivity inversion analysis method for estimating a resistivity change in the ground and a displacement of electrodes has been developed by using sparse regularization technique. The developed method estimates horizontal and vertical displacements to the survey line. A 2D numerical simulation was conducted to clarify an effectiveness of the developed method. As a result, the developed method can be estimated both the resistivity distribution and the electrode displacement. The estimated electrode displacement error was up to 3% to the electrode spacing. Applying the developed method to field data is necessary to demonstrate an effectiveness of the developed method in future studies.	42) Numerical simulation of an analysis of resistivity and electrode displacement by resistivity monitoring
		*Hiroshi Kisanuki(1) 1:OYO
Jun. 6	10:10 - 10:30　　　 The data measured by the High-frequency AC electrical survey system are affected by surface skin effects, leading to results that differ from the actual subsurface resistivity structure when using con-ventional DC electrical resistivity inversion methods. To address this, we have been developing a deep learning-based technique to remove the skin effect and produce data suitable for DC resistivity in-version.This study explored the optimal deep learning approach by varying the hyperparameters and neural network structure. Notably, introducing a convolutional neural network (CNN) architecture signifi-cantly improved the accuracy of skin effect removal. The results demonstrate the potential of deep learning to overcome the limitations of high-frequency AC electrical surveys, paving the way for more reliable subsurface characterization through the integrated use of EM and DC methods.	43) Eliminating the Effect of Skin Effects in VLF-AC band Electrical Survey System Measurement Data Using Deep Learning
		*Junya Shinohara(1),Motoharu Jinguuji・Toshiyuki Yokota(2),Takumi Ueda(3) 1:Grad School, Waseda Univ.,AIST,2:AIST,3:Waseda Univ.
Jun. 6	10:30 - 10:50　　　 Since the shield tunneling method does not allow checking ahead of the tunnel face directly, encountering unexpected geological conditions causes accidents. To solve this problem, we examine the possibility of detecting resistivity anomalies ahead of the tunnel face by applying electrical logging. Using a horizontal multilayer response calculation code and a potential calculation code for arbitrary electrode configuration using the finite element method, we calculate the potential response based on the electrode configuration of the electrical logging in the ahead of tunnel model and quantitatively examined the detection capability of the resistivity logging layer against subsurface resistivity anomalies.	44) Numerical Method for Geological Prediction ahead of Tunnel Face based on Electrical Logging
		*Shimon Yoda・Takumi Ueda(1),Issei Sato・Ryohsuke Tsuji・Hideki Nagatani・Kenichi Kawano(2) 1:Waseda Univ.,2:Kajima Technical Research Institute
Jun. 6	10:50 - 11:10　　　 This article introduced the background and outlook for the establishment of the ``Study Committee on the Compatibility of Weak Radio Stations with Ground Penetrating Radar Radiation Radio Waves''. Ground penetrating radar has become an essential technology in modern society, but it is strongly recommended that it be used in compliance with the Radio Law. Particularly at this point in time, it is important to prevent unnecessary leakage of radio waves into the air.	45) Electromagnetic Wave Radiation from GPR
		*Motoyuki Sato(1),Kei-ichi Suzuki(2),Ko Sano(3) 1:Tohoku University,2:Kawasaki Geological Eng.,3:Oyo Co.

VENUE
	International Conference Center, Waseda University, Tokyo, Japan and ONLINE

SCHEDULE
	Tuesday , June 4, 2024
		Openning Speech	Room No.1 (3F)	09:45-09:50
		__Speaker:	Keiichi SUZUKI (Kawasaki Geological Engineering Co. Ltd.; President of SEGJ)
		Technical Sessions	Room No.1 (3F)	10:00-15:00
		Technical Sessions	Room No.2 (3F)	10:00-15:00
		Poster Core Time	Room No.1 (3F)	15:20-17:20
		Exhibition	Room No.3 (3F)	11:00-17:20

	Wednesday, June 5, 2024
		Technical Sessions	Room No.1 (3F)	09:30-11:30
		Technical Sessions	Room No.2 (3F)	09:30-11:10
		General Meeting	Room No.1 (3F)	12:50-14:30
		Executive Sessions	Room No.1 (3F)	15:00-17:00
		__Chair:	Jun MATSUSHIMA (Univ. of Tokyo, GSFS; Vice-President of SEGJ)
		__Presentation(1):	Initiatives for “Building a SIP Smart Disaster Prevention Network” Yasushi TAGUCHI (NIED)
		__Presentation(2):	Past history and expectations for the future Toshihiro UCHIDA (AIST)
		Exhibition	Room No.3 (3F)	09:30-17:00
	Thursday, June 6, 2024
		Technical Sessions	Room No.1 (3F)	09:30-11:50
		Technical Sessions	Room No.2 (3F)	09:30-11:10
		Exhibition	Room No.3 (3F)	09:30-11:00

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LIST OF EXHIBITORS
	ACT Electronics Corp. Geofive Co.,Ltd. Hakusan Corporation INPEX LAZOC Incorporated Terra Corporation

LIST OF ADVERTISEMENTS
	Geophysical Surveying Co., Ltd.(GSC) ITOCHU Techno-Solutions Corpration(CTC) JGI, Inc. Kawasaki Geological Engineering Co. Ltd.(KGE) Sumiko Resources Exploration & Development Co.,Ltd.

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