Japan Geoscience Union Meeting 2019

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[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS04] Interdisciplinary studies on pre-earthquake processes

Thu. May 30, 2019 1:45 PM - 3:15 PM A02 (TOKYO BAY MAKUHARI HALL)

convener:Katsumi Hattori(Department of Earth Sciences, Graduate School of Science, Chiba University), JANN-YENQ Liu(Institute of Space Science, National Central University, Taiwan), Dimitar Ouzounov(Center of Excellence in Earth Systems Modeling & Observations (CEESMO) , Schmid College of Science & Technology Chapman University, Orange, California, USA), Qinghua Huang(Peking University), Chairperson:Jann-Yenq Liu(National Central University, Taiwan), Toshiyasu Nagao

2:30 PM - 2:45 PM

[MIS04-04] Temporal Variation and Statistical Assessment of b value

*weiyun xie1, Katsumi Hattori1, Peng Han2 (1.chiba university, 2. Southern University of Science and Technology )

Keywords:b-value, AIC

The Gutenberg-Richter Law describes frequency-magnitude distribution of earthquakes. A number of studies have shown that the slope (b value) of the relationship between frequency and magnitude decreased before large earthquakes. In this paper, we investigate the temporal variation of the b value in the Hokkaido and Tohoku regions, Japan and the Wenchuan region, China, respectively, where M 8.0+ earthquakes occurred in the new century. The magnitude of completeness (Mc) in the catalog is evaluated by combining the maximum curvature (MAXC) technique and the bootstrap approach. Then, the b value and its uncertainty is computed by using the maximum likelihood estimation. The Akaike Information Criterion (AIC) with the bootstrap approach is introduced to statistically assess the temporal variation of b values and quantify the significance level. The results show decrease trends of the b value prior to the 2003 Tokachi Earthquake (M8.0) in Hokkaido, the 2011 Tohoku Earthquake (M9.0), and the 2008 Wenchuan Earthquake in China. In addition, the decrease of b values shows certain statistical significance few months before the three M8.0+ great earthquakes. It is concluded that the b value with statistical assessment may contain potential information for future large earthquake preparation.