This paper describes an efficient approach to high-resolution time-reversal source imaging simulation. Dense seismograph network records are backpropagated from stations to the hypocentre through a 3-D subsurface structure model to estimate the initial source wavefield at the earthquake initiation time. By assimilating high-density observational data into the time-reversal wave propagation, a clearer source image can be determined, even for deep and distant earthquakes, than is achievable with conventional source imaging. The effectiveness of data-assimilation-based source imaging by a time-reversal wave propagation simulation with a 3-D heterogeneous structural model was demonstrated using recordings from a nationwide strong-motion seismograph network during the 2007 Off Niigata, Japan, M_w 6.6 earthquake, and the 2007 Off Ibaraki, Japan,M_w 6.8 earthquake. Such data-assimilated-based simulations are also effective for early forecasting of strong ground motions caused by large earthquakes through fast time-advancing simulations based on the current assimilated wavefield. We will discuss the feasibility of a disaster prevention system for the early forecasting of strong motion disasters due to large earthquakes, based on repeatedly estimating source parameters and forecasting strong motions in future time based on the current assimilated wavefields.

中文翻译：

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基于同化密集地震记录的时间反转波传播模拟的高分辨率源成像

本文介绍了一种高分辨率的时间反转源成像仿真的有效方法。密集地震仪网络记录通过3-D地下结构模型从测站反向传播到震中，以估计地震发生时的初始震源波场。通过将高密度观测数据吸收到时间反转波传播中，与常规震源成像相比，即使对于深远地震，也可以确定更清晰的震源图像。基于数据同化源成像由时间反转波传播模拟具有3-d异质结构模型的有效性是在2007年关闭新泻期间使用的记录从一个全国性的强震仪网络证明，日本，中号_瓦特6.6级地震和2007年关闭茨城，日本，中号_W¯¯ 6.8级地震。通过基于当前同化波场的快速时间提前模拟，这种基于数据辅助的模拟对于有效预测大地震引起的强地面运动也非常有效。我们将在反复估算震源参数并根据当前同化波场预测未来时间的强震的基础上，讨论防灾系统在大地震造成的强震早期预报中的可行性。