2007 Fiscal Year Final Research Report Summary
Geomorphological Study for Better Prediction of Large Earthquakes Generated by Active Faults
| Project/Area Number |
17200053
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geography
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| Research Institution | Hiroshima Institute of Technology |
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Principal Investigator |
NAKATA Takashi Hiroshima Institute of Technology, Faculty of Environmental Studies, Professor (60089779)
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| Co-Investigator(Kenkyū-buntansha) |
OKUMURA Koji Hiroshima University, Graduate School of Letters, Professor (10291478)
IMAIZUMI Tosifumi Tohoku University, Graduate School of Science, Professor (50117694)
KUMAMOTO Takashi Okayama University, Graduate School of Natural Science, Associate Professor (60285096)
堤 浩之 京都大学, 大学院・理学研究科, 准教授 (60284428)
WATANABE Mitsuhisa Toyo University, Faculty of Sociology, Professor (30222409)
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| Project Period (FY) |
2005 – 2007
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| Keywords | active fault / earthquake / solid earth physics |
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| Research Abstract |
Basic data for accurate assessment of seismogenic behavior of active faults when re-activated causing large earthquakes, are geometry of active faults, location of asperities and rupture initiation, direction of rupture propagation, etc. In order to obtain these data, we compiled a database on fault slip distribution along the 98 major active fault zones in Japan selected for National Seismic Hazard Maps for Japan by The Earthquake Research Committee, the Headquarters for Earthquake Research Promotion. Data were collected from articles and reports on these faults before 2001 as well as 'Digital Active Fault Map of Japan' (Nakata and Imaizumi, edited 2002), and compiled as an Excel file, and processed into GIS format. The database contains location, vertical and horizontal slips and estimated slip rates together with method of measurement on fault related features and their ages.
This database is the first product of its kind, but is still far from substantial level, especially on slip r
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ate data. However, we believe that this database is useful to roughly locate asperities on active faults for better estimation of strong ground motion.
We also carried out careful interpretation of large-scale air-photographs for more detailed mapping of active faults, paying much attention to minute tectonic landform and obtained important information about extent of active faults, that is closely related to the magnitude of future earthquakes.
Laser imagery technique is applied to obtain comprehensive features of typical reverse fault (Senya fault in NE Japan) and strike-slip fault (Adera fault in Central Japan), and tested several methods for obtaining fault slip from detailed DEM images.
We analyzed slip rate along faults (zones) in order to find section(s) of large slip rate distribution, presuming that section(s) may be coincide with location of asperities on subsurface fault plane. Base on geometric criteria such as branching features of active fault traces and characteristic pattern of vertical-slip distribution along the fault traces as tools to predict location of surface rupture initiation and rupture length of future earthquakes (Nakata and Goto (1998)), we proposed dynamic fault model for future large earthquakes. Less
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