Ground Motion Prediction Using Virtual Earthquakes

这项研究的动机是这样一个事实，即在大地震震中附近几乎没有对震动强度的定量测量。关于地面震动强度的信息至关重要，因为结构工程师使用这些信息来设计抗震结构。我们将进一步开发和应用一种新的方法来预测未来地震的震动强度，这种方法不直接依赖于记录地震，而是利用周围的地震场来预测。环境场由固体地球中的地震波组成，这些地震波是由海洋中的波浪作用产生的。我们可以用这些来开发？虚拟地震？使用部署在地球上我们预计未来将发生地震破裂的位置的地面运动传感器。虚拟地震量化了当这样的地震发生时将发生的震动。具体地说，我们的研究将通过改进震动强度的校准来推进这种方法，将其应用于我们预计震动强烈且可能对建筑物造成问题的特别关注的区域，并将该技术扩展到较短的周期，这对抗震设计很重要。周围运动预测是地震地震学的关键重要领域，因为它是了解地震行为的多学科努力满足社会对减轻地震损失的关注的领域。我们建议改进和应用一种利用环境地震场构造虚拟地震来预测地面运动空间变化的新方法。虚拟地震方法是可能的，因为构成环境场的波，以及大地震中的波，通过相同的复杂地质结构传播，并以相同的方式受到影响。虽然这种方法没有考虑非线性效应，也没有涉及震源特征，但它确实为预测强烈影响地震震动强度的复杂线性波传播效应提供了一种真正的新方法。这项拟议的研究旨在通过以下方式提高虚拟地震方法的准确性和适用性：(1)提高测量振幅的可靠性，(2)探索尚未纳入地面运动预测方程的复杂盆地效应，以及(3)将该技术推广到更短的周期，以便更好地重叠主要地震工程关注的周期范围。继续发展用于地面运动预报的虚拟地震方法对于充分发挥其潜力至关重要。我们将继续与东京大学地震研究所和格勒诺布尔ISTerre的科学家合作。我们还将致力于与墨西哥城墨西哥国立自治大学的科学家和工程师发展一种新的合作。

This research is motivated by the fact that there exist few quantitative measurements of the strength of shaking close to the epicenters of large earthquakes. Information on how strong the ground will shake is critically important because structural engineers use this information to design earthquake-resilient structures. We will further develop and apply a new approach for predicting the strength of shaking in future earthquakes that doesn?t rely on recording earthquakes directly, but uses the ambient seismic field for that purpose. The ambient field consists of seismic waves in the solid Earth that are generated by wave action in the ocean. We can use these to develop ?virtual earthquakes? using ground motion sensors deployed at a location on the Earth where we expect future earthquake rupture to occur. Virtual earthquakes quantify the shaking that will occur when such an earthquake happens. Specifically, our research will advance this method by improving the calibration of the strength of shaking, applying it to areas of particular concern where we expect the shaking to be strong and potential problematic for buildings, and by extending the technique to shorter periods, which are important for earthquake-resistant design.Ground motion prediction is an area of key importance for earthquake seismology as it is where the multi-disciplinary endeavor of understanding earthquake behavior meets the societal concern of mitigating earthquake losses. We propose to improve and apply a new method for predicting spatial variations in ground motion using the ambient seismic field to construct virtual earthquakes. The virtual earthquake approach is possible because the waves that comprise the ambient field, and the waves in large earthquakes, propagate through the same complex geologic structure and are affected by it in the same way. While this approach does not account for nonlinear effects, and does not address earthquake source characterization, it does provide a genuinely new way to predict the complex linear wave propagation effects that strongly influence the intensity of earthquake shaking. The proposed research seeks to improve the accuracy and applicability of the virtual earthquake approach by: (1) improving the reliability of measured amplitudes, (2) exploring complex basin effects that have not been incorporated into ground motion prediction equations, and (3) pushing the technique to shorter periods that better overlap the period range of primary earthquake engineering concern. Continued development of the virtual earthquake approach for ground motion prediction is essential for it to realize its full potential. We will continue our collaboration with scientists at
the Earthquake Research Institute at the University of Tokyo and at ISTerre, Grenoble. We will also work to develop an emerging collaboration with scientists and engineers at Universidad Nacional Autonoma de Mexico, in Mexico City.