1958年2月8日（北京时间），在四川省茂汶-北川县发生了一次6级地震，距离龙门山断裂带很近，为研究历史地震对龙门山断裂带的影响及与2008年汶川地震关系提供了难得的案例。然而，当时地震台网非常稀疏、地震图纸未数字化，地震位置及震源机制解等震源参数精度不高，使得难以确定其发震断层、并研究其与汶川大地震的关系。本项目计划在此次地震附近架设5台宽频地震仪，进行2年的观测，基于背景噪声提取这些流动台与拉萨、昆明、北京等固定台之间的格林函数；搜集1958年北川地震的图纸记录，并进行数字化；对比地震波形与噪声格林函数，准确测定此次地震的位置；并利用波形测定震源深度、机制解、破裂性方向性，判断发震段层面；计算此次地震在龙门山断裂带上造成的应力变化，从而探讨其与汶川大地震的关系。同时也希望本项目能为历史上其它中强地震的震源参数准确测定及发震机理研究提供一个参考方案。

On February 8th, 1958, an M6 earthquake occurred near Longmenshan fault in the Maowen-Beichuan region, and this event provided valuable case for studying interaction with the 2008 Wenchuan Earthquake. However, due to very sparse seismic network and limited waveform data, source parameters of the earthquake was not well resolved and the ruptured fault plane was not known, hampering studies of its interaction with Wenchuan earthquake. We plan to install a few portable seismometers around the epicenter of the M6 event, and retrieve Green's function from ambient noise, then refine epicentral location; and we will also collect historical seismograms and digitize them to get waveforms and resolve rupture directivity and fault plane. Thereafter, we study the interaction of the M6 earthquake and the great Wenchuan earthquake. This project will also be helpful for studying other historical earthquakes many decades ago.