Earthquake Prediction: Nine Major Earthquakes in China (1966-1976)

ISBN-13: 9783642647697 / Angielski / Miękka / 2011 / 332 str.

Zongjin Ma; Zhengxiang Fu; Yingzhen Zhang

Opis

Floods, earthquakes, hurricanes and typhoons are the major natural disas ters in the world, among which the least understood are seismogenic processes_ With highly concentrated populations and rapidly developing economy, social requirements for earthquake prediction are becoming more and more pressing. The seismic region in Mainland China is situated at the eastern edge of the Eurasian seismic system, and is the largest intracontinental region of shallow strong earthquakes in the world, as a result of the collision of the Indian Ocean plate and the underthrusting of the west Pacific Ocean plate. Since the beginning of this century, there have been on average two strong earthquakes of Mover 7 every 3 years, of which at least one has caused catastrophic losses. From 1966 to 1976, China was struck by successive large earthquakes, of which nine with M over 7 (that is, the 1966 M7. 2 Xingtai earthquake;the 1969 M7. 4 Bohai earthquake; the 1970 M7. 7 Tonghai earthquake;the 1973 M7. 9 Luhuo earthquake; the 1974 M7. 1 Yongshan earthquake; the 1975 M7. 3 Haichang earthquake; the 1976 M7. 4 Longling earthquake; the 1976 M7. 8 Tangshan earthquake; the 1976 M7. 2 Songpan earthquake) occurred in the densely popu lated areas east of longitude 98 0 E, causing very severe casualties and damage. According to statistics, about 300,000 people have been killed by these earthquakes."

Spis treści

1 Introduction — History of Earthquake Prediction Work and Subject Matters for Prediction Research.- 2 Characteristics of Earthquake Sequences.- 2.1 Basic Parameters of the Nine Large Earthquakes.- 2.2 Features of Aftershock Sequences.- 3 Tectonic Environments of the Earthquakes.- 3.1 Crustal Layering and Tectonic Deformation of North China.- 3.2 Regional Tectonic Features of the North China Seismic Region.- 3.3 Hypocentral Tectonics of Four Strong Earthquakes in North China.- 3.4 Regional Tectonic Features of the Sichuan-Yunnan Seismic Region in Southwest China.- 3.5 Hypocentral Tectonics of Five Large Earthquakes in the Sichuan-Yunnan Region.- 4 Seismicity Patterns.- 4.1 Regional Seismicity Rate and Energy Release.- 4.2 Spatial Distribution of Regional Seismicity.- 4.3 Foreshocks and Swarms.- 4.4 Seismic Wave Anomalies and Spectra.- 5 Anomalous Variations of the Geophysical Field.- 5.1 Apparent Resistivity Changes in the Shallow Crust.- 5.2 Variations in Electrical Properties of Deep Crustal Media.- 5.3 Gravity Variations.- 5.4 Variations of the Geomagnetic Field.- 6 Crustal Deformation and Anomalous Variations of Stress.- 6.1 Geodetic Measurements.- 6.2 Across-fault Measurements, Tilt and Sea-level Observations.- 6.3 Inversion of Focal Parameters from Crustal Deformation Data.- 6.4 Fault Creep.- 6.5 Anomalous Earth Stress Variations.- 7 Abnormal Changes of Ground Water (Gas).- 7.1 Process of Anomalous Changes of Ground Water (Gas) Before and After Large Earthquakes.- 7.2 Process of Impending Abnormal Variations of Ground water (Gas) Prior to a Large Earthquake.- 7.3 Discussion.- 8 Unusual Atmospheric Phenomena Before Large Earthquakes.- 8.1 Variations of Atmospheric Pressure.- 8.2 Variations of Rainfall.- 8.3 Variations of Physical Meteorology.- 8.4 Abnormal Behaviour of Animals.- 9 Large-scale Regional Anomalous Phenomena.- 9.1 Large-scale Regional Connections of Seismicity.- 9.2 Large-scale Regional Microscopic and Macroscopic Anomalous Phenomena.- 10 Comprehensive Analyses of Time-Space Variations of Anomalous Phenomena Before and After Large Earthquakes.- 10.1 Comprehensive Analyses of Temporal Processes of Anomalous Phenomena.- 10.2 Common Features of the Spatial Distribution of Anomalous Phenomena.- 10.3 Mechanical Analysis of Common Features of Anomalous Variations.- 10.4 Differences in Time-Space Distributions of Anomalous Phenomena.- 11 Sources of Tectonic Earthquakes.- 11.1 Source Physics of Tectonic Earthquakes.- 11.2 “Locking” of Source Rupture Planes and Stress Distribution.- 11.3 “Unlocking” Conditions of Source Fracture Planes.- 11.4 “Unlocking” Types of Source Fracture Planes and Aftermath.- 11.5 Classifications of Seismic Sources.- 11.6 Seismic Energy.- 12 Earthquake Field.- 12.1 Concept of the Earthquake Field.- 12.2 Methods for Studying Basic Crustal Stress Fields of the North and Southwest China Regions, and Principal Research Results.- 12.3 Mechanical Models of Crust and Evolution of the Earthquake Field.- 12.4 Results of Finite Element Analyses of the Earthquake.- 13 Earthquake Episodes.- 13.1 Concept of the Earthquake Episode.- 13.2 Episodic Phenomena of Seismicity in North China.- 13.3 Generality of Seismic Episodes.- 13.4 Global Comparisons of Seismic Episodes and Preliminary Discussion on the Causes of Earthquake Episodes.- 14 Fundamental Understanding Earthquakes in Continental China and Ideas on Step-by-step Earthquake Prediction.- 14.1 Basic Knowledge on Earthquakes in Mainland China.- 14.2 Thoughts About a Program for Step-by-step Earthquake Prediction.