Visualization of attenuation structure and faults in incoming oceanic crust of the Nankai Trough using seismic attenuation profiling

Earth, Planets and Space

Kazuo Nakahigashi¹  Tetsuro Tsuru¹  Jin-Oh Park²  Yukari Kido³  Tetsuo No⁴ 

[1] Academic Assembly, Tokyo University of Marine Science and Technology (TUMSAT);Atmosphere and Ocean Research Institute, The University of Tokyo;Center for Deep Earth Exploration, Japan Agency for Marine-Earth Science and Technology (JAMSTEC);Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology (JAMSTEC);

关键词: Seismic attenuation;    Fault;    Oceanic crust;    Earthquake;    Nankai Trough;   

DOI  :  10.1186/s40623-018-0803-y

来源: DOAJ

【 摘 要 】

Abstract Seismic attenuation properties were tested as indicators of lateral variation in geological structures and detection of faults within poorly reflective oceanic crust, on a seismic survey line along the Nankai Trough. We can specify both sedimentary structures by configuration of reflections and faults by offsetting of reflections on seismic reflection profiles. This procedure is often applied to analyze geological structures and existence of faults within sedimentary layers; however, it is almost impossible to analyze them within igneous oceanic crust because seismic reflections are inherently invisible there. Therefore, we applied seismic attenuation profiling to visualize geological structures and faults within poorly reflective oceanic crust. As a result, oceanic crust altered by late-coming volcanisms as well as damaged by intraplate earthquakes was imaged as extremely high-attenuation property, which was clearly distinguished from normal oceanic crust. Many faults were observed in the sedimentary unit on the seismic reflection profile, whereas possible lower segments of the faults were imaged as high-attenuation stripes in the oceanic crust on the seismic attenuation profile. Thus, the effectiveness of seismic attenuation profiling to structural and fault imaging within poorly reflective oceanic crust was successfully demonstrated.

【 授权许可】

Unknown