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| 1 | Study on the velocity structure of the crust in Southwest Yunnan of the north-south seismic belt—Results from the Menghai-Gengma-Lushui deep seismic sounding profile显示文摘Southwest Yunnan, located in the southern segment of the north-south seismic belt, is one of the regions with strong tectonic movement and seismic activity in China. Study on the characteristics of tectonic setting and deep geophysical field in the region is an important issue in basic science. In 2013, we conducted a 600-km-long Menghai-Gengma-Lushui profile of deep seismic wide-angle reflection/refraction and high-resolution seismic refraction in Southwest Yunnan. In this paper, we use 6 groups of clear intracrustal P-wave phases picked from the seismic record sections of 11 shots to build a velocity structure model of basement and 2D crustal P-wave of the region by using finite difference inversion and ray travel time forward fitting technology. The results show that, from south to north, the crust gradually thickens along the profile and its basement shows a significant lateral heterogeneity. In the vicinity of the Nanting River fault, the basement structure shows the character of alternate depressions and uplifts, and the shallowest basement is about 1.0 km. In the vicinity of Tengchong and Lancang, the basement is about 5.0 km deep. The velocity of the middle and lower crust in the region generally increases with the increasing of depth. At the block boundary and beneath the fault tectonic belt, the velocity contours show apparent irregularity and the P-wave velocity changes sharply. In this region, the Moho gradually deepens from south to north with relatively large lateral undulations. The shallowest point of the Moho is located near Menghai at a depth of about 32.0 km. The deepest point of the Moho is located near Tengchong at a depth of about 40.5 km. Between Gengma and Yongde, the Moho shows significantly fast uplifting and depressing with an amplitude of about 4.0 km. Beneath the Nanting River fault, Longling-Ruili fault, Dayingjiang fault and Tengchong volcano, the basement velocity structure, 2D crustal P-wave velocity structure, distribution of average profile velocity and intracrustal interface spreading also show significant changes from the basement to the top of the Moho, indicating that the crustal velocity and medium physical properties beneath the fault tectonic belt are apparently different from the crustal materials on its both sides, which suggests that these faults should be in a certain scale and may extend to the lower crust or the top of the upper mantle. The earthquakes in the region mainly occurred at a depth of 10–20 km, and the seismic activity is related to the intracrustal medium velocity difference and fault belt distribution. The results can serve as the important data of the crust-mantle structure for the analysis of the deep tectonic setting, earthquake precise positioning, seismogenic structure modeling of the seismic activities in Southwest Yunnan, as well as the important reference for the evaluation of seismic hazard and the planning of earthquake disaster mitigation of this region. | WANG ShuaiJun LIU BaoJin ZHANG JianShi LIU BaoFeng DUAN YuLing SONG XiangHui DENG XiaoGuo MA CeJun ZANG YiRan | 2015 | Science China Earth Sciences2015，58，12： | 13 |
| 2 | 南北地震带滇西南地区地壳速度结构与构造研究:勐海-耿马-泸水深地震探测剖面结果显示文摘位于南北地震带南段的滇西南地区是中国地质构造运动和地震活动较为强烈的地区之一.该区的地质构造背景和深部物理场特征研究是重要的基础科学问题.2013年,在滇西南地区完成了一条长600 km的勐海-耿马-泸水深地震宽角反射/折射和高分辨地震折射联合探测剖面,利用获得11次爆破地震记录截面上6组清楚的壳内P波震相,采用有限差分反演和射线走时正演拟合技术构建了该区的基底速度结构和地壳二维P波速度结构模型.结果显示:沿剖面地壳厚度由南向北逐渐加厚,基底形态呈现出明显的横向起伏变化,在南汀河断裂带附近,基底结构呈现出凹、隆相间的变化形态,基底埋深最浅处约为1.0 km,在腾冲与澜沧附近,基底埋深约为5.0 km.该区中、下地壳速度总体呈现出随深度的增加而增大的变化特征,在块体边界和断裂构造带的下方,速度等值线出现明显紊乱和P波速度的突变.本区莫霍面深度由南向北逐渐加深,且横向起伏变化较大,莫霍面最浅处位于勐海附近,其深度约为32.0 km,最深处位于腾冲附近,深约40.5 km.在耿马与永德之间,莫霍面出现快速上隆和下凹的明显变化,其变化幅度约为4.0 km.在南汀河断裂带、龙陵-瑞丽断裂、大盈江断裂和腾冲火山区的下方,基底速度结构、地壳二维P速度结构、剖面平均速度分布和壳内界面展布还出现从基底至莫霍面顶部的明显变化,显示出断裂构造带下方的地壳速度和介质物性与其两侧的地壳物质具有明显的差异,暗示这些断裂不但具有一定的规模,而且可能延伸至下地壳或上地幔顶部.该区地震主要发生在10~20 km的深度范围内,且地震活动呈现出与壳内介质速度差异、断裂带分布的相关性.研究结果可为分析研究滇西南地区地震活动的深部构造背景、地震精确定位、构建发震构造模型等提供重要的壳幔结构数据,为评价该区的地震危险性和防震减灾规划的制定提供重要参考. | 王帅军 刘保金 张建狮 刘宝峰 段玉玲 宋向辉 邓晓果 马策军 臧怡然 | 2015 | 中国科学:地球科学2015，45，12： | 10 |
| 3 | 地震学衰减层析成像进展显示文摘全球和区域地震波衰减模型揭示了地球内部滞弹性的非均匀结构,为解释地球内部温度、熔体和挥发分分布、分析地球动力学过程和地震震源机制等提供了新的启示.近年来,地震学衰减层析成像在面波及背景噪声衰减成像、体波衰减成像、区域震相及尾波衰减成像、全波形衰减成像的理论与应用方面均取得了实质性进展.在此基础上本文列举了一些地震学衰减层析成像研究中正在开拓和发展的方向. | 戴启立 闪昊 孟昆 包雪阳 | 2022 | 地球与行星物理论评2022，53，6： | 1 |
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