| 摘要: |
| 地震广泛发生于板块的汇聚边界，并表现出多样性。全球多数8级以上和所有9级以上的地震都发生在板块界面即俯冲断层，此类板间地震及其引发的海啸会给人类社会带来巨大的灾难。本文聚焦于孕育此类大地震的地震带及其下方的慢地震带区域，阐述断层热-力学在研究地震活动过程中发挥的重要作用和潜在的应用。在目前对地震发生时间尚无法有效预测的前提下，了解地震发生的地理位置和最大震级对防震减灾工作尤为重要。俯冲断层的热-力学特征可以：（1）借助岩石学特征，圈定大地震发生的上下边界，估算潜在发生大地震的震级；（2）借助海底热流和地形观测，确定俯冲断层强度，推断大地震发生的地理位置；（3）借助岩石学特征和地震观测，推断断层流变学特征（脆性摩擦与黏性蠕滑），建立与实测地震的对应关系，如地震带与其下方的慢地震带分别对应着两段相互分离的脆性摩擦区域。以上研究都离不开热流观测对研究结果的约束，然而目前对俯冲带的热流观测还相对不足。西太平洋周边拥有多个典型俯冲带，开展这些区域特别是马里亚纳俯冲带的热流观测是研究俯冲断层热-力学的重要依据和补充。 |
| 关键词: 俯冲带 地震 慢地震 热结构 断层强度 流变学 |
| DOI：10.11693/hyhz20170900233 |
| 分类号:P31 |
| 基金项目:中国科学院战略性先导科技专项（A类），XDA11030102号；国家自然科学基金青年项目，41406063号；中国科学院海洋地质与环境重点实验室开放基金，MGE2015KG01号，MGE2014KG01号。 |
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| THERMO-MECHANICS OF INTERPLATE SEISMICITY AT SUBDUCTION ZONES |
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GAO Xiang1,2
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1.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;2.Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China
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| Abstract: |
| Earthquakes usually occur at convergent margins. All the M≥9 earthquakes and most of the M≥8 earthquakes locate at subduction megathrusts. These earthquakes and induced tsunami together could bring horrible disasters to human society. The review article attempts to summarize the significant importance and potential applications of fault zone thermo-mechanics on studying seismicity, with focus on the seismogenic zone and its downdip, the slow earthquakes zone. Since earthquake prediction is not viable at the moment, understanding maximum magnitude and exact spatial location of a potential earthquake are much more important. Thermo-mechanics of fault zone can help us to (1) define the upper and lower boundaries of megathrust earthquakes, and then calculate the potential maximum earthquake size; (2) infer fault zone strength and location of great megathrust earthquakes from heat flow measurements and bathymetry; (3) indicate the fault zone rheology (frictional vs. viscous) and its relation to seismic behaviors; for example, two separated frictional segments are correlated with the seismogenic zone and the slow earthquakes zone, respectively. Studies on these issues rely largely on heat flow measurements. Unfortunately, heat flow measurements are insufficient at most subduction zones. As one of the most classic subduction zones around west Pacific Plate margin, the Mariana subduction zone provides us a perfect field laboratory on studying thermo-mechanics of a subduction fault zone, if enough reliable heat flow data could be obtained in this margin. |
| Key words: subduction zone earthquake slow earthquakes thermal structure fault strength rheology |
