Clustering Characteristics Of Spatial-temporal Distribution Of Earthquakes In Different Tectonic Regions

Numerous data show that spatial and temporal (ST) distribution of earthquakes is characterized by complication, stratification and inheritance, and has varied generation causes. Studies on these features have been highly appreciated by scientists in seismology, geology, geophysics and statistics. And the clustering characteristic of earthquake distribution is one of important aspects in this field. It is of importance to understanding earthquake rules and earthquake prediction. Some scholars have made studies on this topic and achieved profuse results. Their work is focused on the clustering structure of seismic event distribution, and less involved in other physical parameters. Although some studies have been concerning with ST distribution of seismic energy release, there is get no a systematic research reported on the clustering features of all physical parameters in seismicity. And more attention should been paid to the distribution in time. On the other hand, some researchers have used statistical method to analyze seismicity and obtained statistical parameters or models to describe non-uniform distribution of events. But multiscale analysis on this feature is still rare.In general, ST distribution of earthquakes is associated with tectonic settings. It exhibits varied features in different tectonic areas. In this thesis, I choose seismicity data of the China mainland, Taiwan area, and New Zealand to study clustering characteristics of ST distribution of earthquakes in different tectonic regions.The purpose of this work is to analyze the ST distribution structure of various physical parameters of seismicity and its clustering features, and then discuss its variations with tectonic settings.The specific approaches are as follows:(1). Considering the regional differences of tectonics and geodynamics, the China mainland if first divided into eastern and western China regions. Based on geological research, eastern China is further subdivided into northeast China, North China and South China; and western China into Xijiang and Qinghai-Xizhang regions. Taiwan area is treated as a special as it is located at a plate boundary. New Zealand is regarded as a whole tectonic unit.(2). The emphasis of this work is put on the heterogeneity of ST distribution of various physical parameters and its clustering features. The relevant parameters concerning with magnitude of seismicity for each tectonic area are first calculated. When necessary, observation data are reorganized.(3). By using the multiscale significance test methods in time and space, the non-uniform features of physical parameter distribution in varied tectonic settings are analyzed. The possible stratification of such a non-uniform nature is further discussed. In terms of "point interval" and wavelet transformation method, the multifractal characters of physical parameters for each seismic area are revealed. Finally, I discuss the clustering characteristics of seismicity for all the tectonic areas.By the approaches above, this thesis completes the following work: (1). A concept of generalized seismic strain release (GSSR) is proposed and defined. (2). The GSSR is simulated by the non-parameter fitting method. Using the multiscale significance test method, I analyze the ST distribution structure of generalized seismic strain release in regions of different scales, their difference, as well as the effects of space scales used. (3). I employ the "point interval" method of repeated sampling to study the multifractal features of seismicity for all tectonic areas, and compare their existing ranges. In particular, I study the difference of multifractal features between deep and shallow earthquakes in New Zealand. (4). With the wavelet transformation, I study the multifractal singular spectua of seismic strain release, Holder singular index, and multifractal spectrum dimensions for all the tectonic areas selected. Finally, the characteristics and differences of these parameters for all areas are discussed.The results of this thesis are summarized below:(1). The multiscale...