Velocity field in Asia inferred from Quaternary fault slip rates and Global Positioning System observations
Velocity field in Asia inferred from Quaternary fault slip rates and Global Positioning System observations
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DOI：
10.1029/2000jb900045
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发表时间：
2000-08
影响因子：
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通讯作者：
W. Holt;N. Chamot‐Rooke;X. Pichon;A. Haines;B. Shen-Tu;J. Ren
中科院分区：
文献类型：
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作者：
W. Holt;N. Chamot‐Rooke;X. Pichon;A. Haines;B. Shen-Tu;J. Ren
我们对亚洲的第四纪应变率和 238 个全球定位系统 (GPS) 速度进行联合反演，以获得自洽速度场。所有大地速度观测的参考系都是在我们的反演过程中确定的。印度 (IN) 相对于欧亚大陆 (EU) 围绕 (29.78°N, 7.51°E, 0.353° Myr−1) 的旋转极移动，这会产生印度境内沿喜马拉雅山的速度，其大小约为 IN-EU NUVEL-1A 速度大小的 73–76%，矢量方位角为 NUVEL-1A IN-EU 矢量顺时针方向 8–10°方位角。相对于欧亚大陆，中国南方以 9-11 毫米/年的速度沿 110-120° 方向移动，极位置为（64.84°N，156.74°E，0.12° Myr−1）。阿穆尔地块运动在相似的位置具有极点，但速度较慢（64.61°N，158.23°E，0.077°Myr−1），并且大部分阿穆尔-欧亚运动通过跨越贝加尔湖的延伸来容纳。塔里木盆地相对于欧亚大陆绕旋转极（39.24°N，98.2°E，-0.539° Myr−1）移动，天山中西部地区每年缩短约16-18毫米。西藏南部和中北部呈东西向分布分布。在西藏南部，东经 77° 至 92°E 之间，形变场可容纳约 16-19 毫米/年的东西向延伸。我们将预测的地震矩速率与本世纪在亚洲观测到的地震矩速率进行了比较。本世纪中亚和东亚整个地区（2.2×107 km2）观测到的总地震矩率为2.26±0.7×1020 N m yr−1，而预测总地震矩率为2.03±0.066×1020 N m yr−1。 42 个分区内观测到的地震矩速率与预测的矩速率之间的比较反映了从有限持续时间（94 年）的目录中推断长期地震矩速率的过程通常不稳定。需要约 10,000 年的观测周期才能将观测到的地震矩速率的不确定性降低到与模型构造矩速率的不确定性相同的大小（根据 GPS 和第四纪应变速率的联合反演推断）。我们表明，一般来说，通过考虑高于截止震级的地震数量（mb ≥ 5.0，1965 年 1 月 1 日至 1999 年 1 月 1 日期间），可以从地震活动目录中推断出与模型构造矩率的更好相关性。
We perform a joint inversion of Quaternary strain rates and 238 Global Positioning System (GPS) velocities in Asia for a self-consistent velocity field. The reference frames for all geodetic velocity observations are determined in our inversion procedure. India (IN) moves relative to Eurasia (EU) about a pole of rotation at (29.78°N, 7.51°E, 0.353° Myr−1), which yields a velocity along the Himalaya within India that is ∼73–76% of the magnitude of the IN-EU NUVEL-1A velocity and a vector azimuth that is 8–10° clockwise of NUVEL-1A IN-EU vector azimuth. Relative to Eurasia, south China moves at 9–11 mm/yr in the direction 110–120° with a pole position (64.84°N, 156.74°E, 0.12° Myr−1). Amurian block motion has a pole position in a similar location but at a slower rate (64.61°N, 158.23°E, 0.077° Myr−1) and most of the Amurian-Eurasia motion is accommodated by extension across Lake Baikal. Tarim Basin moves relative to Eurasia about a pole of rotation at (39.24°N, 98.2°E, −0.539° Myr−1) and ∼16–18 mm/yr of shortening is accommodated across the west central Tien Shan. There is distributed E-W extension throughout both southern and north central Tibet. Within southern Tibet, between the longitudes of 77°E to 92°E, the deformation field accommodates ∼16–19 mm/yr of E-W extension. We compare predicted seismic moment rates with those observed in this century in Asia. Total observed seismic moment rates within the entire area of central and east Asia (2.2×107 km2) in this century are 2.26±0.7×1020 N m yr−1 as compared with a predicted total rate of 2.03±0.066×1020 N m yr−1. Comparisons between observed and predicted moment rates within 42 subregions reflect the generally unstable process of inferring long-term seismic moment rates from a catalog of limited duration (94 years). An observation period of ∼10,000 years would be required to reduce uncertainties in observed seismic moment rate to the same size as the uncertainties in model tectonic moment rates, inferred from the joint inversion of GPS and Quaternary rates of strain. We show that in general, a better correlation with model tectonic moment rate is inferred from the seismicity catalog by considering the numbers of earthquakes above a cutoff magnitude (mb ≥ 5.0, for the period January 1, 1965, to January 1, 1999).