岩石破坏位移协调系数与GNSS数据的地震预测方法研究  

Research on earthquake prediction methodology utilizing the displacement coordination coefficient of rock failure and GNSS

作　　者：冯增朝[1] 沈永星 赵阳升[1] FENG ZengChao;SHEN YongXing;ZHAO YangSheng(Key-Laboratory of In-situ Property-improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学原位改性采矿教育部重点实验室,太原030024

出　　处：《地球物理学报》2024年第11期4204-4219,共16页Chinese Journal of Geophysics

基　　金：国家自然科学基金青年基金项目(12102293)资助。

摘　　要：本文以小尺度的岩石破坏试验为基础, 提出了以岩石表面多点位移信息预测岩石失稳破坏的短临前兆指标-位移协调系数(DCC).基于GNSS数据, 分析了DCC指标在大尺度地震中的演化特征, 提出了基于GNSS数据的DCC指标地震预测方法.研究结果表明: 在岩石弹性承载阶段, DCC在较低水平波动;当承载达到岩石峰值强度95%~99%时, DCC出现突增是预测岩石失稳破坏的重要前兆指标.通过大量试验统计, 确定了岩石从弹性变形到塑性变形转变的岩石弹塑性临界阈值范围为0.98±0.2.当DCC大于弹塑性临界阈值时, 岩石即将发生失稳破坏.基于GNSS数据计算获取三个地震案例震前的DCC指标与岩石破坏过程中DCC指标的演化特征具有相似性, 当DCC指标达到弹塑性临界阈值后大地震将在3~16天发生, 验证了将DCC指标作为预测地震发生短临前兆的有效性.同时, 地震发生区域可以利用震前GNSS数据绝对变形场重构方法通过异常变形区进行确定, 且根据DCC达到阈值时刻的异常变形区面积与地震震级呈对数关系, 可估算地震震级.研究结果对基于GNSS数据建立和完善地震短临预测方法具有重要的意义.This study introduces a novel short-term precursor indicator, the Displacement Coordination Coefficient (DCC), derived from small-scale rock failure experiments, to predict rock instability and failure by utilizing multi-point displacement information on the rock surface. Employing GNSS data, the research investigates the evolutionary characteristics of the DCC indicator during large-scale earthquakes and presents an earthquake prediction methodology based on GNSS data and DCC indices. Findings reveal that during the elastic bearing phase of rocks, DCC experiences minimal fluctuations;however, a sudden surge in DCC at 95%~99% of the peak strength emerges as a pivotal precursor for anticipating rock instability. Through comprehensive experimental statistics, the study establishes the elastic-plastic transition threshold range for rocks (0.98±0.2), delineating the shift from elastic to plastic deformation. Once DCC surpasses the elastic-plastic critical threshold, imminent rock instability and failure follow suit. By calculating DCC indices from GNSS data across three earthquake cases, the study identifies parallels in the evolution of DCC indices between the pre-earthquake period and the rock failure process. This validates the efficacy of DCC as a short-term precursor, with significant seismic events transpiring within 3~16 days after DCC breaches the elastic-plastic critical threshold. Concurrently, the earthquake occurrence area is determined using the absolute deformation field reconstruction method with pre-earthquake GNSS data. The area of the anomalous deformation zone when DCC reaches the threshold logarithmically correlates with earthquake magnitude, enabling the estimation of earthquake magnitude. The study's outcomes bear crucial implications for the development and enhancement of short-term earthquake prediction methodologies grounded in GNSS data.

关 键 词：弹塑性阈值 GNSS连续观测 震前变形 绝对变形场 地震短临预测 

分 类 号：P315[天文地球—地震学]