Japan Geoscience Union Meeting 2014

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Oral

Symbol S (Solid Earth Sciences) » S-VC Volcanology

[S-VC53_28PM2] volcanic activities and tectonics

Mon. Apr 28, 2014 4:15 PM - 4:45 PM 413 (4F)

Convener:*Nobuo Geshi(Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology), Takuya NISHIMURA(Disaster Prevention Research Institute, Kyoto University), Ryuta FURUKAWA(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Daisuke MIURA(Geosphere Sciences, Civil Engineering Research Laboratory, Central Research Institute of Electric Power Industry), Takeshi Hasegawa(Department of Earth Sciences, College of Science, Ibaraki University), Kiyoshi Toshida(Geosphere Science Sector, Civil Engineering Research Laboratory, Central Research Institute of Electric Power Industry), Chair:Yasuhisa Tajima(NIPPON KOEI CO.,LTD.)

4:30 PM - 4:45 PM

[SVC53-P07_PG] Paleostress analysis of dilational fractures using genetic algorithm

3-min talk in an oral session

*Atsushi YAMAJI1 (1.Kyoto University)

Keywords:real-coded genetic algorithm, magma pressure, mixed Bingham distribution, dike, vein

The attitudes of dilational fractures, including dikes and veins, are clues to the paleostresses under which the structures were formed. A software tool for clustering their 3D orienatations has been developed in this study. The software fits mixed Bingham distributions to them, and detects girdle, elliptical and circular clusters. In addition, it determines the three principal stress axes, stress ratios and maximum fluid pressure for each of the clusters. Fitting a mixed Bingham distribution is not a well posed problem, because the mathematical inversion is highly non-linear and its object function is multimodal. It is demonstrated that genetic algorithm is more effective than the expectation-maximization algorithm which was used by previous researchers (Yamaji and Sato, 2011).