High-Resolution Seismic Study of Subducted Slabs

我们建议研究地震和爆炸体波的波形、振幅和传播时间，以研究0 - 1500深度范围内俯冲板块的详细速度结构。Creager和Jordon（1986）提出，千岛群岛和其他俯冲带下的俯冲板块渗透到至少1000公里的深度是解释深层地震的走时异常所必需的。这种穿透也会影响地震体波的振幅和波形。我们最近开发的方法允许计算高速俯冲板块的波形和振幅效应。对现有数据的初步审查表明，我们可以用这些新方法测试和改进板的地震模型。我们还建议完善上地幔板块的模型，因为从经验上看，上地幔板块比深部板块产生更大的波形、振幅和时间异常。我们的方法也可以帮助定位地震相对于高速板块发生的位置（例如，在顶部或在中间）。为了了解650 km不连续面附近和以下板块的几何结构，需要对深部事件体波的振幅、波形畸变和时序进行协调。

We propose to investigate the waveforms, amplitudes, and traveltimes of body waves from earthquakes and explosions to examine the detailed velocity structure of subducting slabs in the depth range 0 to 1500. Creager and Jordon (1986) propose that penetration of subducting slabs under the Kurile Islands and other subduction zones to depths of at least 1000 km is necessary to explain travel time anomalies of deep earthquakes. Such penetration would also affect the amplitudes and waveforms of the body waves from earthquakes. Methods we have recently developed allow the calculation of the waveform and amplitude effects of high-velocity, subducting slabs. A preliminary review of available data show that we can test and refine seismic models of slabs with these new methods. We propose, as well, to refine models of slabs in the upper mantle, which empirically cause even greater waveform, amplitude and timing anomalies than the deep slabs. Our method may also help to locate where the earthquakes occur relative to the high-velocity slab (e.g., toward the top or in the middle). Reconciliation of the amplitude, waveform distortion, and timing of body waves from deep events is necessary to understand the geometry of slabs near and below the 650 km discontinuity.