کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6428393 1634739 2015 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
High-resolution lithospheric structure beneath Mainland China from ambient noise and earthquake surface-wave tomography
ترجمه فارسی عنوان
ساختار لیتوسفری با وضوح بالا در زیر سرزمین اصلی چین از نویز محیطی و توموگرافی سطح موج زلزله
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
چکیده انگلیسی


- Use unprecedented amount of seismic data from ambient noise and earthquake data.
- Construct an S-velocity model for mainland China with much improved resolution.
- North China lithosphere shows strong east-west structural variations.
- Underthrusting of Indian Plate beneath Tibet shows complex geometry.

We present a new high-resolution shear-velocity model of the lithosphere (down to about 160 km) beneath China using Rayleigh-wave tomography. We combined ambient noise and earthquake data recorded at 1316 seismic stations, the largest number used for the region to date. More than 700,000 dispersion curves were measured to generate group and phase velocity maps at periods of 10-140 s. The resolution of our model is significantly improved over previous models with about 1-2° in eastern China and 2-3° in western China. We also derived models of the study region for crustal thickness and averaged S velocities for upper and mid-lower crust and uppermost mantle. These models reveal important lithospheric features beneath China and provide a fundamental data set for understanding continental dynamics and evolution. Different geological units show distinct features in the Moho depth, lithospheric thickness, and shear velocity. In particular, the North China Craton (NCC) lithosphere shows strong east-west structural variations with thin and low-velocity lithosphere in eastern NCC and thick and high-velocity lithosphere beneath western NCC and the lithosphere of the Ordos Block seems to have undergone strong erosion. The results support the progressive destruction of the NCC lithosphere from east to west at least partly caused by the thermal-chemical erosion of the cratonic lithosphere from the asthenosphere. Another pronounced feature of our model is the strong lateral variations of the mantle lithosphere beneath the Tibetan Plateau (TP). The Indian lithosphere beneath the TP shows variable northward advancement with nearly flat subduction in western and eastern TP and steep subduction in central TP with evidence for the tearing of Indian lithosphere beneath central TP, which may be important for the riftings at the surface in Himalayas and southern TP. The low-velocity zone in northern TP shows strong correlation with the region of the mid-Miocene to Quaternary potassic magmatism, suggesting that delamination of lithosphere may have played an important role in the rise of the TP.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 417, 1 May 2015, Pages 132-141
نویسندگان
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