重复发生的深度地震:证据表明,在极深处的断层被重新激活
1Department of Earth and Planetary Sciences, Washington University, St. Louis, MO 63130, USA.
概括
加板块的深度地震揭示了重复的破裂模式. 这些地震事件表明,断层再激活受到热切割不稳定性和反复破裂过程的强烈控制.
科学领域:
- 地震学 地震学
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
背景情况:
- 沉浮板块内的深度地震为复杂的构造过程提供了洞察力.
- 了解地震破裂机制对于地震危险评估至关重要.
研究的目的:
- 为了识别和描述加潜伏区中重复的地震序列.
- 研究控制深度地震破裂和复发的物理机制.
主要方法:
- 在加板块中确定了具有几乎相同波形的深度地震.
- 利用交叉关联方法进行精确的地震转移.
- 分析了地震集群,空间分布和复发间隔.
主要成果:
- 发现了三个不同的深度地震集群,每个集群形成平面结构 (长度10-30公里),发生10-30次地震.
- 观察到同一地点的地震,表明相同断层段的重复破裂.
- 发现了复发间隔的逆时间分布,表明对故障重新激活的时间控制.
- 确定地震双重发生在几个小时内,与热扩散过程一致.
结论:
- 失控的热剪切不稳定性可能解释了暂时聚集的,类似波形的深度地震.
- 特定断层区域的反复破裂和类似的破裂模式表明加板块可预测的地震行为.
- 这些发现突出了热效应在深度地震发生和复发中的重要作用.
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