| There has long suffered from different magnitude earthquake in the world, especially the earthquakes frequently occurred in recent years, which suggests that seismic activity is about to enter the active stage or has entered the active stage. Earthquakes are a regular occurrence and noise seriously affects on seismic region and safety of surrounding residents' normal life and property. Therefore, studying on seismic activity which provides theory and method to support for seimic disaster prevention and mitigation is imperative. However, seismic activity has complexity and randmoness and geophysical model is not enough precision and understanding of the earth's crust has certain blindness, which has caused that the forecast of seismic activity become the global problem.There are a lot of the study cases which have applied to earthquake activity. Studying of seismic acticvity in time series and spacial distribution serial features shows that spatial and temporal(ST) distribution of earthquakes is characterized by complication, stage, stratification and inheritance, and has varied generation causes. Therefore, studying level of spatial and temporal(ST) distribution of earthquakes directly influences on the level of earthquake prevention and mitigation work in a way, and is an efficient way that obain seismic active regularity. Fractal theory is a new method of nonlinear science. As an important branch of nonlinear science, fractal theory has been applied to in the field of seismic activities. Due to fractal theory almost entirely out of the limit of factors in the study of seismic activity, such as geophysical model, which has become a new starting point and gradually developed and matured.Circum-Pacific seismic belt is the largest seismic zone in the world, which geographical environment and geological structure background are complex and large range of influence. So studying of the Circum-Pacific seismic belt of seismic activity has been a hot spot of research in the field of seismology. Based on this, we select the Circum-Pacific seismic belt during 1900 to 2015, more than one hundred years of seismic data directory, as the research object from the perspective of principle of fractal theory. Firstly, we have to integrity analysis to get a full set of the earthquake catalogue in method of G-R( Gutenberg-Richter). Secondly, we apply fractal theory to seismic activity in temporal and spatial sequnce characteristics, and combined with the geological and tectonic environmental characteristics to analyze and compare sutdy of result. Lastly, we obtain the Circum-Pacific seismic belt of seismic activity in temporal and spatial sequnce characteristics.In single fractal analysis, the Circum-Pacific seismic belt of seismic activity in time series and spacial distribution serial features are similarities and fractal structure. In time series, the Circum-Pacific seismic belt seismic activity has been relatively active phase. In spatial distribution serial, the Circum-Pacific seismic belt seismic activity has agglomeration. In the multifractal, the Circum-Pacific seismic belt seismic activity has obvious multifractal properties of complex in time series and spacial distribution serial features. Therefore, the Circum-Pacific seismic belt seismic activity has certain to follow rules in time series and spacial distribution serial features. In a word, research results show that space-time distribution of seismic activity of the seismic belt has certain characteristics. In spatial sequence, it present a set of cluster, sparse, periodic and fractal structure. In temporal sequence, it present sparse dense, strong or weak alternately cycle and fractal structure characteristics, especially for the above magnitude 7 earthquake magnitude. |
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