[S04-4] Historical and macroseismic studies of earthquakes IV

[S04-4-01] Methodology to Determine the Parameters of Historical Earthquakes in China

^○Jian Wang¹, Guoliang Lin², Zhe Zhang¹ (1.Institute of Geophysics, China Earthquake Administration, Beijing, China, 2.Yunnan Seismological Bureau, China Earthquake Administration, Kunming, China)

invited

China is one of the countries with longest culture history. Meanwhile China has been suffered very heavy earthquake disaster, so abundant earthquake recordings remained. In this paper, we try to outline some basic information about China historical sources of earthquakes and the achievements of research. There were two large-scale collections of historical earthquake archives in China. We also introduce China intensity scale and the editions of historical earthquake catalogues. Total four formal editions of “The Catalogue of Chinese Earthquake" were compiled. Spatial-temporal and magnitude distribution of historical earthquake are analyzed briefly. The practice procedures of tradition methods were illustrated. Generally, the parameters of an historical earthquake were determined according to the relation between the parameters and intensity data. Several such relations were listed which often used in China. Owing to rely heavily on the historical earthquake archives, the traditional method has its limitation.

Besides traditional methods, we also illustrate a new approach to amend the parameters of historical earthquakes or even identify candidate zones for large historical or palaeo-seismic earthquakes. In the new method, a relationship between instrumental recorded small earthquakes and strong historical earthquakes is built up. Geophysics implication of new method was analyzed. The modern-day seismicity can point out the locations of persistent weaknesses in the lithosphere. Such persistent has also been observed on a much smaller scale in the location of acoustic emissions (AE) during cyclic loading in laboratory rock deformation tests. From view of fracture mechanics, the occurrence of a strong earthquake means that the local crust medium has been experienced a process of changing. The new method might help us to judge historical earthquake parameters and amend them, even find a new candidate site.