在北卡斯卡迪亚边缘沿着地震震的广泛深度分布
Honn Kao1, Shao-Ju Shan, Herb Dragert
1Geological Survey of Canada, Pacific Geoscience Centre, 9860 West Saanich Road, Sidney, British Columbia V8L 1B9, Canada. hkao@nrcan.gc.ca
Nature
|August 12, 2005
概括
卡斯卡迪亚潜伏区的震动在40公里深度范围内偶尔会发生. 这些地震事件表明流体参与,并可能表明沿板面接口的短暂滑动或分散的偶发滑动.
科学领域:
- 地球科学 地球科学 地球科学
- 地震学 地震学
- 地质物理学 地质物理学
背景情况:
- 卡斯卡迪亚潜水带有能力产生大地震 (M(w) = 9) 由于其锁定离岸板块接口.
- 每14个月左右会出现一次带有震般地震特征的偶发性表面移位,与长期变形相反.
研究的目的:
- 调查在卡斯卡迪亚海底沉降区发生的类似震的地震事件的空间分布和特征.
- 了解这些偶发性地震现象的潜在机制和影响.
主要方法:
- 分析测量数据以推断板块接口的行为.
- 分析地震数据以描述震的分布和深度.
- 震动位置与地震反射器和板块接口的相关性.
主要成果:
- 地震分布在一个狭窄的水平带内超过40公里的深度范围内.
- 许多地震发生在板面接口上方的强震反射器附近,这是一个缺乏局部地震的地区.
- 震的地震过程似乎与液体有关.
结论:
- 观测到的震动深度范围表明与应力场变化有关,这些变化是由更深层的卡斯卡迪亚板块接口上短暂的滑动引起的.
- 另外,这些发现可能表明,情节性滑动比以前假设的更为扩散.
- 了解这些震源对于评估卡斯卡迪亚地区的地震危险至关重要.
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