11:00 AM - 1:00 PM
[SSS07-P18] DSeis Report 4: Calibration of 3D seismic velocity field around the seismogenic zone of the M5.5 Orkney earthquake ｰ Comparison between DD-relocated aftershocks, 3D reflection data, and mafic/ultramafic intrusives.
Keywords:Seismicity streaks, sill dike complex mafic/ultramafic, Seismogenic zone drilling, Mine gology information, 2014 M5.5 Orkney earthquake
We could calibrate the 3D velocity structure for the 3D seismic reflection cube (Figure left) which include most part of the aftershocks for the 2014 Orkeny M5.5 earthquake. Drastic change in the dolomite velocity from < 6 km/s to ~ 6.5 km/s resulted in the significant vertically downwad shift in the seismic reflection image by ~ 300m.
Before this calibration we couldn't discuss the spatial relationship between the sills and reflectors, both of which dip 20 degrees toward the south east, and the aftershock streaks as shown in Figure (right). The modified vertical depth section much better spatially correlates with the streaks of the aftershocks. We wil detail the outcomes in our presentation.
This report is related to the other ICDP DSeis reports, which include an FY2021 activity overview (M-GI32), the dense stress measurements (S-SS07), material analysis for the core recovered from altered ultramafic dyke that hosted the aftershocks of the M5.5 earthquake (S-CG46).
The DSeis team consists of seismologists, geologists, geomicrobiologisits, rock mechanists, mining engineers from Japan, South Africa USA, Switzerland, Germany, India, and Australia. The DSeis project is build on JST-JICA SATREPS project and Kakenhi (21224012) and is supported by ICDP, JSPS Core-to-Core Program, Ritsumeikan University, MEXT 2nd Earthquake and Volcano Hazard Reduction Research, and Kochi Core Center.
Before this calibration we couldn't discuss the spatial relationship between the sills and reflectors, both of which dip 20 degrees toward the south east, and the aftershock streaks as shown in Figure (right). The modified vertical depth section much better spatially correlates with the streaks of the aftershocks. We wil detail the outcomes in our presentation.
This report is related to the other ICDP DSeis reports, which include an FY2021 activity overview (M-GI32), the dense stress measurements (S-SS07), material analysis for the core recovered from altered ultramafic dyke that hosted the aftershocks of the M5.5 earthquake (S-CG46).
The DSeis team consists of seismologists, geologists, geomicrobiologisits, rock mechanists, mining engineers from Japan, South Africa USA, Switzerland, Germany, India, and Australia. The DSeis project is build on JST-JICA SATREPS project and Kakenhi (21224012) and is supported by ICDP, JSPS Core-to-Core Program, Ritsumeikan University, MEXT 2nd Earthquake and Volcano Hazard Reduction Research, and Kochi Core Center.