大平行重力变化预测了潜水带的地震行为
Teh-Ru Alex Song1, Mark Simons
1Seismological Laboratory, Division of Geological and Planetary Science, California Institute of Technology, Pasadena, CA 91125, USA. alex@gps.caltech.edu
Science (New York, N.Y.)
|August 2, 2003
概括
大地震主要发生在带有负沟平行重力异常 (TPGA) 的俯冲区域. 这些地震模式在100万年内保持不变,与前弧地质结构和板块界面摩擦有关.
科学领域:
- 地质物理学 地质物理学
- 地震学 地震学
- 构造学 构造学 构造学 构造学
背景情况:
- 俯冲区是大地震发生的关键地点.
- 了解地震性的空间变化是地震危险评估的关键.
- 对前弧地质结构在控制地震发生中的作用进行了辩论.
研究的目的:
- 调查沟平行引力异常与大地震发生之间的关系.
- 为了确定俯冲区的地震行为是否在地质时间尺度上是静止的.
- 探索前弧地质结构对地震活动的影响.
主要方法:
- 对地震分布与沟平行重力异常 (TPGA) 的分析.
- 地震行为与前弧地质结构的相关性.
- 模拟板面界面摩擦特性对重力和地震性的影响.
主要成果:
- 大地震主要发生在TPGA极为负的地区.
- 具有强烈阳性TPGA的地区具有明显较低的地震性.
- 地震行为中的空间变化至少在100万年内是静止的.
- 观察到的相关性与控制前弧特征的摩擦性质变化一致.
结论:
- 前弧地质结构,特别是TPGA,是大地震发生的强有力的指标.
- 俯冲区的地震行为在很大程度上是由板面界面摩擦的静止变化控制的.
- 这些发现对理解地震危险和板块构造学有意义.
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