The Crustal Isostatic State of Sichuan-Yunnan Region and
Its Relationship with Regional Earthquakes
1 School of Geology Engineering and Geomatics,Chang’an University,126 Yanta Road,Xi’an 710054, China
2 School of Environment Science and Tourism, Nanyang Normal University, 1638 Wolong Road, Nanyang 473061, China
Abstract Using the model CRUST 1.0, we analyze the structure of upper crust thickness and the moho discontinuity in Sichuan-Yunnan region. Then we calculate the regional isostatic moho discontinuity based on the Airy isostatic theory. With the difference between the isostatic and the real moho discontinuity, we study the state of crustal equalization in the Sichuan-Yunnan region. Comparing the map of upper crust thickness with the depth distribution diagram of regional earthquakes, we found that regional earthquakes mainly occurred in the upper brittleness crust. The crustal isostatic apparently shows that the Sichuan basin is in an isostatic state. However, the Longmen mountain’s fault zone poses a state which is out of the isostatic, and represents the most remarkable disequilibrium area in Sichuan-Yunnan region, whose north side presents positive equilibrium (+6 km), south side presents negative equilibrium (-6 km) and southwest side presents positive equilibrium (+6 km). All of this possibly reflects that the deep crust material beneath Longmen Mountain’s fault zone is undergoing a dramatic differentiation, adjustment and intense exchange of energy.
JIANG Yongtao,ZHANG Yongzhi,WANG Shuai. The Crustal Isostatic State of Sichuan-Yunnan Region and
Its Relationship with Regional Earthquakes[J]. jgg, 2015, 35(4): 585-588.
JIANG Yongtao,ZHANG Yongzhi,WANG Shuai. The Crustal Isostatic State of Sichuan-Yunnan Region and
Its Relationship with Regional Earthquakes[J]. jgg, 2015, 35(4): 585-588.
