一种基于台阵技术的大震震级测定新方法探索

近年来大震震例显示，快速准确测定大震震级的研究还有很大进步空间和紧迫社会需求。本项目拟系统论证一种基于区域地震台阵和全球地震台网联合测定大震震级新方法。分析该方法优劣点、误差及改进空间，并与目前通用的W-phase测定震级方法比对及有机结合，为全球大震震级快速测定工作提供新思路。.基于近10-20年来大震（Mw>=7.0）观测数据，利用反投影方法，估计震源持时。计算直达P波最大位移。推导新震级计算公式。通过分析理论和观测地震波数据，研究不同震源机制、特殊（海啸、超剪切地震等）地震的震源持时及直达P波最大位移特征,及其对震级测定影响。分析近台P波“双三重值”对震源持时测定的影响及可能改进策略（引入格林函数）。总结地震尺度律（Scaling law），探索震源复杂性对震级测定的影响。.比对新方法和W-phase反演方法的优劣点，探索可能改进空间（基于震源持时的时窗可变W-phase反演）。

This proposal aims to further develop a new magnitude scale for large earthquakes based on dense seismic arrays and Global Seismic Network (GSN) in recent 10-20 years. We are going to improve this method by both theoretical and observational approaches, and compare the results with the magnitudes derived from the W-phase inversions. This new method can help to promptly and accurately determine magnitudes of Global large earthquakes ..We are going to apply back-projection methods to determine source durations of available global large earthquakes (Mw >= 7.0) using seismic array data recorded in China, America, Europe, and Japan. Then estimate maximum displacements of the direct P waves recorded at GSN stations (20 to 85 degree to the epicenter). A weighted regression is applied to obtain the parameters for estimating magnitudes. Afterward we will discuss the statistic features for the source durations and the maximum displacements of direct P waves, and investigate their relations to focal mechanisms, geodynamic environments, and intriguing earthquakes such as tsunami earthquakes and supershear earthquakes. We will also evaluate their impacts on the magnitude determinations. Summarize the source durations and try to deduce a scaling law and compare it with present scaling laws...We will compare the new method with the W-phase inversion method based on several cases using simulated real-time seismic data, and try to make improvements for both (W-phase inversion with varying length window).