A Study for developing the technique of extracting indistinct seismogenic faults

Takada, Keita*

JNC TJ7420 2005-106, 139 Pages, 2004/03

JNC-TJ7420-2005-106.pdf:59.93MB

We discuss developing the technique of extracting indistinct seismogenic faults such as a case of partly existing displacement on the ground surface and indistinct active faults. We maped active faults and possible active faults that have possibility to induce earthquakes by aerial photograph interpretation around the Chugoku district, southwestern Japan and Chubu district, central Japan. Then we make a field survey around epicentral area of the 2000 Tottori-ken Seibu earthquake. The result of the field survey shows characteristics of lineaments that faulted during 2000 earthquake. We compared results of interpretation with several datas, for example seismicity, geology, gravity, GPS, and summarize notable point for extracting indistinct seismogenic faults.

Distribution of coseismic crustal strain change around active faults

Haraguchi, Tsuyoshi*

JNC TJ7420 2005-078, 124 Pages, 2003/03

Long-term estimation of the groundwater flow is one of the important themes to characterize geological environment in deep underground. Coseismic deformation of the crust is a factor for changing groundwater condition.In this report, We discuss the effect on faults and clucks around the epicenter due to the crustal strain and stress change. We tested simple fault models, and calculated strain changes from recent earthquakes (1995 Hyogoken-nambu earthquake, 2000 Tottoriken-seibu earthquake, 1993 Hokkaido Nansei-oki earthquake).Active fault data is available to make models for calculation of crustal strain change because results from simple fault model show similar trend to complex fault geometry model. We made simple fault models by known active fault data, and estimated future strain change and crustal deformation from earthquakes in central Japan.

Data for concealed earthquake source fault survey

Haraguchi, Tsuyoshi*

JNC TJ7420 2005-110, 28 Pages, 2001/03

Western Tottori earthquake occurred on Oct. 6, 2000 without surface fault rupture, even though the focus was sallow. For discuss earthquake effects to geological environment, we have to consider not only surface fault rupture, but also concealed earthquake source faults. This report introduces several data to find out the earthquake source faults in the region of Western Tottori earthquake. We collected data of topographical linerments, geology, structural geology, geodetic, seismology, and compared each data. Based on these data, we suggest the methods for this kind of survey.