四川地区地壳上地幔速度结构的初步研究
PRIMARY STUDY OF CRUSTAL AND UPPER MANTLE VELOCITY STRUCTURE OF SICHUAN PROVINCE
-
摘要: 本文使用10个工业爆破和154个天然地震,以及四川台网50个台站记录的 P 波组到时等资料,以龙门山断裂和二次大地构造单元分界线为界(图1),得出四川东部盆地和西部高原不同的地壳上地幔平均速度模型.若简单地采用双层地壳模型,则东部地壳厚40-41km,壳下 P 波速度为8.15-8.2km/s,壳内上层平均速度为5.82-5.9km/s,厚18km,下层平均速度为6.47-6.54km/s,厚22-23km;西部地壳厚61-64km,壳下 P 波速度为7.8-7.84km/s,壳内上层平均速度为5.82-5.98km/s,厚27-28.5km,下层平均速度为6.94-7.0km/s,厚34-35.5km.此模型为四川地区走时表提供了依据,也为研究地壳上地幔结构与地震的关系,研究我国大陆地块的构造演化及形成等,提供了有用的约束.Abstract: Arrival-time data from 10 industrical explosions and 154 earthquakes recorded by 50 stations of the Sichuan Seismic Network are analyezd to formulate the different average curstal and mantle velocity models for the east basin and west tableland of Sichuan divided by the Longmenshan fault and secondary boundaries of land structure blocks. If a simple two-layer crust is assumed, we have obtained: (1) the velocity model in the eastern part has a crustal thickness of 40-41km, an upper mantle velocity (P wave) of 8.15-8.2 km/s, an 18 km thick upper crust with an average velocity of 5.82-5.9 km/s, and a 22-23 km thick lower crust with an average velocity of 6.47-6.54 km/s; (2) the velocity model in the western part has a crustal thickness of 61-64km, an upper mantle velocity (P wave) of 7.8-7.84 km/s, a 27-28.5 km thick upper crust with an average velocity of 5.82-5.96 km/s and a 34-35.5 km thick lower crust with an average velocity of 6.94-7.0 km/s. This model provides the hasis for the regional travel-time tables of Sichuan and useful constraints for researches the relationship of the crustal and mantle structure with earthquakes, the structural evolution and formation of the China land blocks and so on.
-
-
[1] 何茂富,四川地区区域重力场的基本特征,四川地震,1984, 2: 9——11,
[2] 赵友年、李春生、赖绍民、咸向明,四川省大地构造若干基本问题(四川省大地构造图简要说明书),31,四川省地质局地质矿产科学研究所出版,1983,
[3] Mitchell, B. J, and B. M. Hashim, Seismic velocity determinations in the new Madrid seismic zone: a new method using local earthquakes, Bull. Seism. Soc. Am., 67, 413——424, 1977
[4] Dobrin, M. B,Introduction to Geophysical Prospecting, and ed., 294——303, McGraw——Hill, New York,1976.
[5] 赵珠,华北地区上地慢速度结构,地球物理学报,超,341——354, 1983.
[6] 宋仲和,朱介寿,安昌强,张丽娟,北京一萨哈林剖面地馒纵向速度结构,地球物理学报,24,310——318,1981,
[7] Cart, D. A. and G. A. Bollinger, A regional crustal velocity model for the Southeastern United Staties,Bull. Seism. Soc. Am., 71, 1829——1847, 1981.
[8] Gupta, I. N., B. W. Barker, J. A. Buretti and Z. A. Der, A study of regional phases from earthquakes and explosions in Western Russia, Bulf. Seism. Soc. Am., 70, 855——872, 1980.
[9] Bruce, R. J. and D. L. Anderson, Travel——times, apparent velocities and amplitudes of body waves, Bull.Seism. Soc. Am., S8, 339——366, 1968.[1] 何茂富,四川地区区域重力场的基本特征,四川地震,1984, 2: 9——11,
[2] 赵友年、李春生、赖绍民、咸向明,四川省大地构造若干基本问题(四川省大地构造图简要说明书),31,四川省地质局地质矿产科学研究所出版,1983,
[3] Mitchell, B. J, and B. M. Hashim, Seismic velocity determinations in the new Madrid seismic zone: a new method using local earthquakes, Bull. Seism. Soc. Am., 67, 413——424, 1977
[4] Dobrin, M. B,Introduction to Geophysical Prospecting, and ed., 294——303, McGraw——Hill, New York,1976.
[5] 赵珠,华北地区上地慢速度结构,地球物理学报,超,341——354, 1983.
[6] 宋仲和,朱介寿,安昌强,张丽娟,北京一萨哈林剖面地馒纵向速度结构,地球物理学报,24,310——318,1981,
[7] Cart, D. A. and G. A. Bollinger, A regional crustal velocity model for the Southeastern United Staties,Bull. Seism. Soc. Am., 71, 1829——1847, 1981.
[8] Gupta, I. N., B. W. Barker, J. A. Buretti and Z. A. Der, A study of regional phases from earthquakes and explosions in Western Russia, Bulf. Seism. Soc. Am., 70, 855——872, 1980.
[9] Bruce, R. J. and D. L. Anderson, Travel——times, apparent velocities and amplitudes of body waves, Bull.Seism. Soc. Am., S8, 339——366, 1968.
计量
- 文章访问数: 1371
- HTML全文浏览量: 43
- PDF下载量: 134
下载:
