标题： 悬崖坍塌前的地震前兆模式和临界点现象 显示英文标题

标题： Seismic precursory patterns before a cliff collapse and critical-point phenomena

摘要： 我们分析了诺曼底海岸西法兰西1-2 103立方米石灰岩悬崖坍塌前的地震活动统计模式。我们表明，在40 Hz-1.5 kHz和2 Hz-10kHz频率范围内，地震活动率和能量的幂律加速在坍塌时间前2小时内定义了3个数量级。同时，地震事件的平均大小朝着失效时间增加。这些现场结果来自于距离岩崩断裂面一个破裂长度距离内的唯一观测站。它们模拟了从物理和数值实验中恢复的“临界点”行为，出现在脆性失效和三级蠕变失效之前。我们对这一首次悬崖坍塌地震监测数据的分析表明，失效的热力学相变模型可能适用于悬崖坍塌。 显示英文摘要

摘要： We analyse the statistical pattern of seismicity before a 1-2 103 m3 chalk cliff collapse on the Normandie ocean shore, Western France. We show that a power law acceleration of seismicity rate and energy in both 40 Hz-1.5 kHz and 2 Hz-10kHz frequency range, is defined on 3 order of magnitude, within 2 hours from the collapse time. Simultaneously, the average size of the seismic events increases toward the time to failure. These in-situ results are derived from the only station located within one rupture length distance from the rock fall rupture plane. They mimic the "critical point" like behavior recovered from physical and numerical experiments before brittle failures and tertiary creep failures. Our analysis of this first seismic monitoring data of a cliff collapse suggests that the thermodynamic phase transition models for failure may apply for cliff collapse.