Active Fault Research Group
Active faults that have repeatedly ruptured in the recent past have potential to generate large earthquakes in the future. In order to reduce the damage due to such earthquakes, it is fundamental to elucidate the distribution, geometry and past behavior of active faults.
We investigate major active faults inland and offshore Japan by integration of various methods such as geological and geomorphological mapping, paleoseismological trenching, boring and seismic profiling to better define the extent and timing of the past rupture events as well as recurrence intervals. On the basis of these paleoseismological data, we evaluate the long-term possibility of future earthquakes for each fault or fault group. These data are gathered into an active fault database and opened to public.
Crustal deformation associated with earthquakes including surface ruptures provides useful insights not only for understanding rupture dynamics but also for extracting past earthquake rupture events from geologic and geomorphic records. We perform field investigation of the crustal deformation immediately after earthquakes.
We also conduct basic study to further improve our capability for identifying active faults with weak geomorphic expressions and for understanding rupture extent and spatial distribution of potential source of moderate earthquakes.
Member
Yukari Miyashita (Leader, Group)
I focus on research in reconstruction of paleoearthquake events of major active faults in Japan to evaluate earthquake potential caused by the faults. I also try to develop a new fault activity evaluation method using mineral, chemical and textural features of fault gouges. My final research target is to understand evolution process of active faults through overlap relation analyses of geological structures and fault rocks from middle crust (seismogenic zone) to land surface.
Takashi Azuma (Senior Researcher)
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Tadashi Maruyama (Chief Senior Researcher)
My research focuses on using the geologic and geomorphic records to understand upper crustal deformation associated with faulting. I investigate Quaternary faulting history by combining field-based geologic investigations (e.g. structural mapping, drilling, trenching) with high-resolution topographic datasets (e.g. LiDAR)
Hisao Kondo (Senior Researcher)
My research focus on paleoseismological works in the field on major active fault zone in Japan, Turkey, and Asian countries. In particular, I have carried out three-dimensional trenching survey across strike-slip faults, in order to reconstruct the timing and displacement associated with paleoearthquake events. I also have interest in recurrence models for large earthquake to assess magnitude and timing of future earthquake occurrence.
Yoshiki Shirahama (Researcher)
I have studied a growth history of the Tibetan Plateau by remote sensing analysis of tectonic landforms, and surface exposure dating by in situ cosmogenic radionuclides. I would like to examine a potential of the surface exposure dating in Japan while investigating active faults based on field survey.
Shreya Arora (AIST Postdoctoral Researcher)
My work involved detailed mapping of the active faults and trenching survey along the Himalayan fault lines to establish the past earthquake chronologies to better assess the imminent seismic hazard to the Himalaya. I have extensively used high resolution satellite data and Optically Stimulated Luminescence (OSL) Dating techniques to support my work. Currently, I am working in the meizoseismal zone of Mw 7.2 1896 Rikuu earthquake, northeast Japan, to determine the slip rates and reconstruct the past earthquake chronologies integrating aerial photo interpretation, LiDAR, borehole data, seismic reflection survey and trenching techniques.
Tam Evan (Research Assistant)
Leggett Kai (Research Assistant)
Fujika Miyamoto (Technical Staff)
I am engaged in update and maintenance of Active Fault Database of Japan. The database contains representative parameters of major behavioral segments shown in the Rupture Probability Map of Major Active Faults in Japan.
Yuko Kono (Technical Staff)