Park Sunyoung, Shin Changsoo, Kim Younglib, Clayton Robert W
Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, 60637, USA.
Department of Energy Resources Engineering, Seoul National University, Seoul, 08826, South Korea.
Sci Rep. 2022 Mar 17;12(1):4613. doi: 10.1038/s41598-022-08732-w.
Studying seismic wave propagation through complex media is crucial to numerous aspects of geophysics and engineering including seismic hazard assessment. In particular, small-scale structure such as sedimentary basins and their edges can have significant effects on high-frequency earthquake ground motion, which is the main cause for the damage to buildings and infrastructure. However, such structural effects are poorly understood due to limitations in numerical and analytical methods. To overcome this challenge, for the first time, we utilize the 3D printing technique to build a scaled-down physical representation of geological structure and perform lab-scale seismic experiments on it. Specifically, a physical model based on the Los Angeles Basin is printed and used as synthetic medium to propagate ultrasonic waves, to mimic seismic wave propagation from local earthquakes. Our results show clear body and surface waves recorded at expected time and locations, as well as waves that are scattered from the basin edges. We find that high-frequency energies are significantly reduced at the basin, which is at odds with the conventional view of basins as ground motion amplifiers. This novel waveform modeling approach with 3D printed Earth models is largely automated and provides an effective means to tackle geophysical problems of significance.
研究地震波在复杂介质中的传播对于地球物理学和工程学的众多方面至关重要，包括地震危险性评估。特别是，诸如沉积盆地及其边缘等小尺度结构可能对高频地震地面运动产生重大影响，而高频地震地面运动是建筑物和基础设施受损的主要原因。然而，由于数值和分析方法的局限性，这种结构效应尚未得到充分理解。为了克服这一挑战，我们首次利用3D打印技术构建地质结构的缩小物理模型，并在其上进行实验室规模的地震实验。具体而言，打印了一个基于洛杉矶盆地的物理模型，并将其用作合成介质来传播超声波，以模拟局部地震的地震波传播。我们的结果显示，在预期的时间和位置记录到了清晰的体波和面波，以及从盆地边缘散射的波。我们发现，盆地处的高频能量显著降低，这与盆地作为地面运动放大器的传统观点相悖。这种采用3D打印地球模型的新型波形建模方法在很大程度上是自动化的，并为解决具有重要意义的地球物理问题提供了一种有效手段。
