Static Source Properties of Slow and Fast Earthquakes
Static Source Properties of Slow and Fast Earthquakes
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DOI：
10.1029/2019jb019028
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
P. Nanjundiah;S. Barbot;S. Wei
中科院分区：
文献类型：
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作者：
P. Nanjundiah;S. Barbot;S. Wei
慢震和快震的震源特征为了解断层的力学性质提供了一个窗口。特别是，平均应力降控制着摩擦力、断层滑动和地震震级的演化。然而，这一重要的震源性质通常是从地震波分析中推断出来的，并且受到许多认识上的不确定性的影响。在这里，我们研究了53个地震和17个慢滑事件的震源性质的逆冲和走滑断层在不同的构造环境中使用滑动分布约束的大地测量结合其他数据。我们确定的宽度，潜力和潜力密度的慢和快震源的基础上静态滑移分布。势密度，概念上定义为平均滑动与破裂半径的比值，是一种滞弹性变形的度量，其偏差有限，来自不同深度和构造环境的刚度差异。走滑地震具有最高的潜在密度，从20到500微应变不等。效力密度是平均较低的大陆逆冲断层和巨型逆冲断层，从10到200微应变，与质心深度的代数减少，表示系统的变化，在主导破裂过程的深度。慢滑移事件代表了一种端元类型的破裂，具有低的效力密度和大的破裂宽度。慢滑事件的效力密度的显著变化影响其矩持续时间标度。震源性质在构造背景、深度和破裂类型上的变化可以用来更好地约束地震活动性的数值模拟，并评估未来地震和慢滑事件的震源特征。
The source characteristics of slow and fast earthquakes provide a window into the mechanical properties of faults. In particular, the average stress drop controls the evolution of friction, fault slip, and event magnitude. However, this important source property is typically inferred from the analysis of seismic waves and is subject to many epistemic uncertainties. Here, we investigate the source properties of 53 earthquakes and 17 slow‐slip events on thrust and strike‐slip faults in various tectonic settings using slip distributions constrained by geodesy in combination with other data. We determine the width, potency, and potency density of slow and fast earthquake sources based on static slip distributions. The potency density, defined conceptually as the ratio of average slip to rupture radius, is a measure of anelastic deformation with limited bias from rigidity differences across depths and tectonic settings. Strike‐slip earthquakes have the highest potency density, varying from 20 to 500 microstrain. The potency density is on average lower on continental thrust faults and megathrusts, from 10 to 200 microstrain, with an algebraic decrease with centroid depth, indicative of systematic changes in dominant rupture processes with depth. Slow slip events represent an end‐member style of rupture with low potency density and large rupture width. Significant variability in potency density of slow‐slip events affects their moment‐duration scaling. The variations of source properties across tectonic settings, depth, and rupture styles can be used to better constrain numerical simulations of seismicity and to assess the source characteristics of future earthquakes and slow slip events.