|
| | Abstract | | Integrated geological and geophysical investigations were conducted at Makuhari-Kaihin Park where significant sand boiling from fissures was observed accompanied with liquefaction caused by the 2011 East Japan Earthquake. The park was reclaimed just after the 1987 East off Chiba Prefecture Earthquake using dredged fine sand and the surface was covered with clayey fill soils up to 5 m in thickness. Because the boiling sand is characterized by fine sand including large amount of shell fragments, it was presumed to be originated from the dredged sand layers. However near-surface geology was still unknown and there were few available drill data around the park. To clarify the near-surface structure and its geophysical properties, we conducted high-resolution near-surface geophysical surveying at the park. As a result, a low S-wave velocity layer was identified at the dredged sand horizon about 3 to 5 m in depths. The survey results shows that it is capable to delineate liquefied layers as anomaly zones in geophysical profiles. |
|
|
|
| |
|