A Comparison of Geodetic and Geologic Rates Prior to Large Strike-Slip Earthquakes: A Diversity of Earthquake-Cycle Behaviors?
A Comparison of Geodetic and Geologic Rates Prior to Large Strike-Slip Earthquakes: A Diversity of Earthquake-Cycle Behaviors?
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DOI：
10.1002/2017gc007014
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发表时间：
2017-12-01
影响因子：
3.5
通讯作者：
Meade, Brendan J.
中科院分区：
文献类型：
--
作者：
Dolan, James F.;Meade, Brendan J.
三个大震级（Mw57.6-7.9）走滑地震发生前的大地测量和地质速率的比较揭示了广泛的行为。具体而言，北安纳托利亚断层沿 1999 年 MW57.6 伊兹米特断裂的大地测量速率为 26-28 毫米/年，比全新世地质速率快 40%。相比之下，2002 年 MW57.9 Denali 地震之前，沿 Denali 断层的大地测量速率约为 6-8 毫米/年，仅约为最新更新世-全新世地质速率（约为 12 毫米/年）的一半。在第三个例子中，存在足够长的震前大地测量时间序列，沿昆仑断层 2001 MW57.8 可可西里断裂的大地测量速率和地质速率大约相等，约为 11 毫米/年。这些结果很难用现有的地震周期模型来解释，这表明它们可能是由于区域运动断层相互作用、岩石圈尺度剪切带强度的时间变化和/或局部相对板块运动速率的变化的某种组合所致。无论这些可变行为的确切原因是什么，这些观察结果表明，地震前的大地测量速率与地质速率之比可能无法诊断下一次地震的时间，正如许多基于流变学的地震周期行为地球动力学模型所预测的那样，或者不同的行为以尚未理解或预测的方式表征不同的断层系统。
Comparison of preevent geodetic and geologic rates in three large-magnitude (Mw57.6-7.9) strike-slip earthquakes reveals a wide range of behaviors. Specifically, geodetic rates of 26-28 mm/yr for the North Anatolian fault along the 1999 MW57.6 Izmit rupture are similar to 40% faster than Holocene geologic rates. In contrast, geodetic rates of similar to 6-8 mm/yr along the Denali fault prior to the 2002 MW57.9 Denali earthquake are only approximately half as fast as the latest Pleistocene-Holocene geologic rate of similar to 12 mm/yr. In the third example where a sufficiently long pre-earthquake geodetic time series exists, the geodetic and geologic rates along the 2001 MW57.8 Kokoxili rupture on the Kunlun fault are approximately equal at similar to 11 mm/yr. These results are not readily explicable with extant earthquake-cycle modeling, suggesting that they may instead be due to some combination of regional kinematic fault interactions, temporal variations in the strength of lithospheric-scale shear zones, and/or variations in local relative plate motion rate. Whatever the exact causes of these variable behaviors, these observations indicate that either the ratio of geodetic to geologic rates before an earthquake may not be diagnostic of the time to the next earthquake, as predicted by many rheologically based geodynamic models of earthquake-cycle behavior, or different behaviors characterize different fault systems in a manner that is not yet understood or predictable.