著者

芝崎 文一郎

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.61, pp.415-423, 2009

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Recent high-resolution observations of crustal movements have revealed the occurrence of slow slip events (SSEs) along the deep parts of subduction interfaces. This report reviews the possible models for SSEs using rate- and state-dependent friction laws. SSEs can be modeled under the condition close to the stability transition. The triggered SSEs can be modeled considering a conditionally unstable cell. The self-triggered SSEs can be reproduced in a region that is unstable but close to being stable. In this case, the ranges of the constitutive law parameters for reproducing SSEs are limited. Further, SSEs can also be modeled by considering the frictional property of an unstable-stable transition zone that exhibits velocity weakening at low slip velocity and velocity strengthening at high slip velocity; this model is proposed on the basis of the results obtained in an experiment using halite around an unstable-stable transition zone. By considering this frictional property, Shibazaki and Shimamoto have reproduced short-term SSEs that are similar to the observed SSEs. This friction law needs to be verified experimentally under conditions that are relevant to the fault zones of SSEs. It is theoretically expected that for slip failure processes the propagation velocity is proportional to the slip velocity. This relationship appears to hold for observed SSEs. Therefore, SSEs can be regarded as slip failure processes occurring at deep subduction plate interfaces.