A spectral expansion approach for geodetic slip inversion: implications for the downdip rupture limits of oceanic and continental megathrust earthquakes
A spectral expansion approach for geodetic slip inversion: implications for the downdip rupture limits of oceanic and continental megathrust earthquakes
复制标题
大地滑移反演的谱扩展方法：对海洋和大陆巨型逆冲地震下倾破裂极限的影响
DOI：
10.1093/gji/ggx408
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发表时间：
2018
影响因子：
2.8
通讯作者：
D. Bassett
中科院分区：
文献类型：
--
作者：
Xiaohua Xu;D. Sandwell;D. Bassett
我们已经开发了一种数据驱动的频谱扩展反演方法，以确定具有良好干涉合成孔径雷达和GPS覆盖的大型逆冲断层地震下倾破裂深度的界限。这种逆理论方法被用来建立一组模型，是一致的观察。此外，逆理论方法表明，滑动模型的空间分辨率取决于两个因素，空间覆盖范围和精度的表面变形测量，和滑动深度。将该方法应用于2010年Mw8.8级Maule地震，结果表明，在19 km深度处的滑动最大值逐渐减小，在140 km深度处为零。相比之下，喜马拉雅山的大陆-大陆巨型逆冲断层地震，例如2015年的廓尔喀地震，在9 km深度处显示出滑动最大值，在1018 km深度处逐渐减小到零。主要的问题是，为什么大陆大逆冲断层地震的最大滑动深度只有海洋大逆冲断层地震的50%。为了理解这种差异，我们开发了一个简单的一维热传导模型，其中包括隆起和表面侵蚀的影响。海洋大型逆冲断层上方的侵蚀率相对较低，导致地热中心在140公里深处出现450-600摄氏度的转变。相比之下，喜马拉雅山脉的平均侵蚀速率相对较高，为1.21毫米/年，导致地热中心在1.20公里处出现450-600摄氏度的转变。基于这些新的观测和模型，我们认为侵蚀速率对温度的影响解释了智利和喜马拉雅山之间孕震区最大深度的差异。
S U M M A R Y We have developed a data-driven spectral expansion inversion method to place bounds on the downdip rupture depth of large megathrust earthquakes having good InSAR and GPS coverage. This inverse theory approach is used to establish the set of models that are consistent with the observations. In addition, the inverse theory method demonstrates that the spatial resolution of the slip models depends on two factors, the spatial coverage and accuracy of the surface deformation measurements, and the slip depth. Application of this method to the 2010 Mw 8.8 Maule Earthquake shows a slip maximum at 19 km depth tapering to zero at ∼40 km depth. In contrast, the continent–continent megathrust earthquakes of the Himalayas, for example 2015 Mw 7.8 Gorkha Earthquake, shows a slip maximum at 9 km depth tapering to zero at ∼18 km depth. The main question is why is the maximum slip depth of the continental megathrust earthquake only 50 per cent of that observed in oceanic megathrust earthquakes. To understand this difference, we have developed a simple 1-D heat conduction model that includes the effects of uplift and surface erosion. The relatively low erosion rates above the ocean megathrust results in a geotherm where the 450–600 ◦C transition is centred at ∼40 km depth. In contrast, the relatively high average erosion rates in the Himalayas of ∼1 mm yr–1 results in a geotherm where the 450–600 ◦C transition is centred at ∼20 km. Based on these new observations and models, we suggest that the effect of erosion rate on temperature explains the difference in the maximum depth of the seismogenic zone between Chile and the Himalayas.
影响因子：
18.3
作者：
Lorito, S.;Romano, F.;Piatanesi, A.
通讯作者：
Piatanesi, A.
影响因子：
3.5
作者：
Bassett, Dan;Watts, Anthony B.
通讯作者：
Watts, Anthony B.