地震动力学:震源分布与岩石圈流变特性(英文)

地震震源分布强烈依赖于构造环境的温度和压力条件。震源机制可使大陆地壳脆性-韧性转换带(下部稳定性过渡边界)的温压条件复杂化。该过渡边界伴随速度弱化作用(有震活动)向速度强化作用(无震活动)的转化。在岩石圈流变和壳幔动力学的基础上研究了与板块边界有关的地震活动,包括板缘地震和俯冲板片地震。俯冲带板缘地震的深度分布受约于脆性摩擦动力机制,而摩擦剪切机制不能满意地解释深震活动,包括俯冲板片地震。这是因为深震震源机制可能与高压、高温条件下的固一固相变有关,而用脆性破裂或摩擦作用来解释就不近合理。以理论与实验研究为依据,本文对与震源物理和震源分布有关的岩石圈流变特性进行了较为深入的论述。

EARTHQUAKE DYNAMICS: SOURCE DISTRIBUTION WITH RESPECT TO LITHOSPHERIC RHEOLOGY

Earthquake source distribution strongly depends on temperature and pressure conditions of the tectonic environments. Focal mechanism complicates the temperature-pressure conditions of the lower stability transition at the brittle-ductile transition boundary of the continental crust, a transition from velocity weakening (seismic) to velocity strengthening (non-seismic). Plate boundary associated earthquakes such as interface and intraslab events are studied on a platform of lithospheric rheology and crust-mantle dynamics. Brittle friction bears dynamic constraints on depth distribution of subduction interface earthquakes. Deep earthquakes, including subduction intraslab events, are not well explained by frictional shearing mechanism, for which a candidate mechanism appears to be associated with solid-solid phase transition at high pressure and temperature conditions where a brittle rupture or frictional processes may not be plausible. Rheological properties relevant to physics of earthquake focus and source depth distribution are critically reviewed based on theoretical and experimental research.