Contemporary uplift of the Sierra Nevada, western United States, from GPS and InSAR measurements
Contemporary uplift of the Sierra Nevada, western United States, from GPS and InSAR measurements
复制标题
DOI：
10.1130/g32968.1
复制
发表时间：
2012-07
期刊：
影响因子：
5.8
通讯作者：
W. Hammond;G. Blewitt;Zhenhong Li;H. Plag;C. Kreemer
中科院分区：
文献类型：
--
作者：
W. Hammond;G. Blewitt;Zhenhong Li;H. Plag;C. Kreemer
现代空间大地测量学最近使人们能够直接观察移动和塑造地球表面的缓慢地质过程，包括板块构造和导致地震的地壳应变积累。更难以直接观测到活跃的山脉增长，因为大地测量在垂直方向上的不确定性较大，而山脉增长通常非常缓慢。对于加州州的Sierra内华达州和美国西部的内华达州，海拔历史是复杂的，既表现出古老的（40-60 Ma）和相对年轻的（<3 Ma）海拔特征。在这里，我们利用高精度的三分量点位置的互补优势，从GPS和毯子覆盖线的视线测量干涉合成孔径雷达（干涉合成孔径雷达）显示，当代垂直运动的内华达州是1和2毫米/年之间。相对于地球的质量中心和相对稳定的内华达州东部，运动是向上的，这表明产生了地形起伏和克服重力的抬升。地幔柱沿着整个山脉分布，介于北纬35° ~ 40°之间，并不集中在局部的、地震成像的地幔下部。这些结果表明，现代内华达州山脉的隆起仍然是活跃的，并可能在<3百万年的时间内产生了整个现代山脉。
Modern space geodesy has recently enabled the direct observation of slow geological processes that move and shape Earth’s surface, including plate tectonics and crustal strain accumulation that leads to earthquakes. More elusive has been the direct observation of active mountain growth, because geodetic measurements have larger uncertainties in the vertical direction, while mountain growth is typically very slow. For the Sierra Nevada of California and Nevada, western United States, the history of elevation is complex, exhibiting features of both ancient (40–60 Ma) and relatively young (<3 Ma) elevation. Here we exploit the complementary strengths of high-precision three-component point positions from the GPS and blanket coverage line-of-sight measurements from interferometric synthetic aperture radar (InSAR) to show that contemporary vertical motion of the Sierra Nevada is between 1 and 2 mm/yr. The motion is upward with respect to Earth’s center of mass and with respect to a relatively stable eastern Nevada, indicating generation of relief and uplift against gravity. Uplift is distributed along the entire length of the range, between latitude 35°N and 40°N, and is not focused near localized, seismically imaged mantle downwellings. These results indicate that the modern episode of Sierra Nevada uplift is still active and could have generated the entire modern range in <3 m.y.