Factors affecting seismic moment release rates in subduction zones
Factors affecting seismic moment release rates in subduction zones
复制标题
俯冲带地震矩释放速率的影响因素
DOI：
--
复制
发表时间：
1984
期刊：
影响因子：
--
通讯作者：
T. Seno
中科院分区：
文献类型：
--
作者：
E. T. Peterson;T. Seno
俯冲带的浅层地震活动量因地区而异。我们通过计算 24 个俯冲带的地震矩释放率和地震滑移率来量化这种地震活动性。为了计算力矩释放，我们将1904年至1980年发生的所有面波震级Ms≥7.0的板间逆冲型事件的地震力矩相加。我们绘制了每个俯冲带地震力矩释放的时程图；这些表现出地震释放模式的差异。对于我们研究的时间窗口不具有代表性的俯冲带，使用重复次数的信息来校正总力矩释放。将力矩释放速率与各种俯冲参数进行比较，以确定哪些因素影响耦合程度。这些参数包括俯冲岩石圈的年龄、上部板块和俯冲板块的绝对速度、收敛速度以及瓦达蒂-贝尼奥夫带的长度、最大深度和倾角。当考虑属于单个俯冲板块的区域时，力矩释放率随着俯冲岩石圈年龄的增加而减小。对于太平洋、科科斯、菲律宾海和印度板块俯冲的区域，这种年龄与时刻释放关系是一致的。太平洋板块俯冲的俯冲带的力矩释放率远高于其他类似年龄板块的俯冲带。属于一个俯冲板块的区域之间存在年龄与力矩释放关系；然而，年龄相似但属于不同板块的区域没有相同的时刻释放率。这表明在单个板块内，年龄是影响地震耦合强度的主要因素，但每个板块作为一个整体都有一个特征性的力矩释放预算。上板块后退的区域往往具有较低的力矩释放率。力矩释放率不随收敛速度增加而增加；在这两个参数之间没有发现简单的关系。力矩释放速率最明显地取决于俯冲岩石圈的年龄和上板块的绝对速度。这是所考虑的变量中两个独立的俯冲带参数。其他变量取决于这两个参数。
The amount of shallow seismic activity in subduction zones varies greatly from region to region. We quantify this seismicity by calculating seismic moment release rates and seismic slip rates for 24 subduction zones. To calculate the moment release, we sum the seismic moment for all interplate thrust-type events with surface wave magnitude Ms≥7.0, occurring from 1904 to 1980. We present a time history plot of the seismic moment release for each subduction zone; these exhibit the differences in the seismic release patterns. For subduction zones where the time window of our study is not representative, the total moment release is corrected using information on repeat times. The moment release rates are compared with various subduction parameters in order to determine which factors influence the degree of coupling. These parameters include the age of the subducting lithosphere, absolute velocities of the upper and subducting plates, convergence velocity, and length, maximum depth, and dip of the Wadati-Benioff zone. The moment release rate decreases as the age of the subducting lithosphere increases, when the zones belonging to a single subducting plate are considered. This age versus moment release relation is consistent for the zones in which the Pacific, Cocos, Philippine Sea, and Indian plates are subducting. The moment release rates for the subduction zones in which the Pacific plate is subducting are much higher than for zones of other plates with similar age. The age versus moment release relation holds among the zones which belong to one subducting plate; however, zones with similar ages but belonging to different plates do not have the same moment release rates. This suggests that within a single plate the age is the dominating factor affecting the strength of seismic coupling but that each plate as a whole has a characteristic moment release budget. Zones with retreating upper plates tend to have lower moment release rates. The moment release rate does not increase with convergence velocity; no simple relationship was found between these two parameters. The moment release rate depends most clearly on the age of the subducting lithosphere and the absolute velocity of the upper plate. These are the two independent subduction zone parameters among the variables considered. The other variables depend on these two parameters.