Lg coda Q and its relation to the geology and tectonics of the Middle East
Lg coda Q and its relation to the geology and tectonics of the Middle East
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DOI：
10.1007/s000240050208
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发表时间：
1998-12-01
影响因子：
2
通讯作者：
Mitchell, BJ
中科院分区：
文献类型：
--
作者：
Cong, LL;Mitchell, BJ
使用反投影方法收集区域地震图，以对中东 1 Hz 处 Lg coda Q (Q(0)) 的横向变化及其频率依赖性 (eta) 进行成像。这些数据包括 1986 年至 1996 年期间在 10 个站记录的 124 条垂直分量轨迹。所得图像揭示了 Q(0) 和 eta 的横向变化。在土耳其和伊朗高原，一个高度变形且构造活跃的地区，Q(0) 的范围约为 150 至 300，最低值出现在安纳托利亚西部，在那里测量到了极高的热弓。该地区发现的低 Q(0) 值与世界其他构造活跃地区的值一致。纵观阿拉伯半岛大部分地区，Q(0)相对稳定，Q(0)在350～450之间变化，盾构区最高，东部盆地最低。所有值均远低于大多数其他稳定地区的值。整个中东地区的低 Q 值可能是由从上地幔迁移到地壳的间质流体引起的，这些流体可能是由已知在那里发生的高温下的热液反应产生的。在阿曼褶皱带（沉积物较厚的地区）也发现了低 Q(0) 值（约 250）。在中东大部分地区，eta 与 Q(0) 成反比变化，其中阿拉伯半岛的值较低 (0.4-0.5)，伊朗和土耳其的值较高 (0.6-0.8)。阿曼褶皱带和安纳托利亚西部的 Q(0) 和 eta 均较低。
Regional seismograms were collected to image the lateral variations of Lg coda Q at 1 Hz (Q(0)) and its frequency dependence (eta) in the Middle East using a back-projection method. The data include 124 vertical-component traces recorded at 10 stations during the period 1986-1996. The resulting images reveal lateral variations in both Q(0) and eta. In the Turkish and Iranian Plateaus, a highly deformed and tectonically active region, Q(0), ranges between about 150 and 300, with the lowest values occurring in western Anatolia where extremely high heat Bow has been measured. The low Q(0) values found in this region agree with those found in other tectonically active regions of the world. Throughout most of the Arabian Peninsula, a relatively stable region, Q(0) varies between 350 and 450, bring highest in the shield area and lowest in the eastern basins. All values are considerably lower than those found in most other stable regions. Low Q values throughout the Middle East may be caused by interstitial fluids that have migrated to the crust from the upper mantle, where they were probably generated by hydrothermal reactions at elevated temperatures known to occur there. Low Q(0) values (about 250) are also found in the Oman folded zone, a region with thick sedimentary deposits. eta varies inversely with Q(0) throughout most of the Middle East, with lower values (0.4-0.5) in the Arabian Peninsula and higher values (0.6-0.8) in Iran and Turkey. Q(0) and eta are both low in the Oman folded zone and western Anatolia.