Energy Budget of Earthquakes and State of Stress on Subduction-zone Megathrusts

本项目拟建立一种准确测定大地震辐射地震能量的方法，并将其应用于俯冲带特大逆冲断层的应力状态研究。辐射地震能量估算是断层带应力状态的重要约束条件。不幸的是，辐射地震能量的测定有很大的不确定性，不同研究人员的估计可能相差10倍以上。特别是，由远震资料得到的值往往比由区域资料得到的值小，这被认为是复杂的震源过程和传播效应的结果。该研究将利用来自全球网络的宽带数据和最先进的方法来计算真实震源破裂模型的合成波形，从而提高能量测定的准确性；P波和S波都将被使用，因为S波携带了95%以上的辐射地震能量。

This project proposes to develop a method to accurately determine seismic energy radiated from large earthquakes, and apply it to study the state of stress on subduction-zone megathrusts. Radiated seismic energy estimates provide an important constraint on the state of stress in fault zones. Unfortunately, the determination of radiated seismic energy is subject to large uncertainties, and estimates by different investigators can differ by more than a factor of 10. In particular, the values derived from teleseismic data tend to be smaller than those determined from regional data, which is believed to result from complex source processes and propagation effects. The research will improve the accuracy of energy determination using broad-band data from global networks and state-of-art methodology for computing synthetic waveforms for realistic source rupture models; both P and S waves will be used, since S wave carry more than 95% of the radiated seismic energy.