天津港“8·12”爆炸事件记录波形分析          下载免费PDF全文

王晨辰  张盛中  杨晓瑜  张冰  李世鑫  刘敏 《地震工程学报》2018,40(1):130-138

利用天津地震台网23个短周期地震仪记录到的2015年8月12日天津港爆炸事件波形数据,对事件进行初步分析和研究。分别使用能量包络线法和波形匹配法,共识别出4次爆炸事件,并结合波形互相关的主事件定位法对爆炸事件进行定位。分析结果表明:第一次爆炸发生的时间为2015年8月12日23时34分4秒,1.77s后发生了规模更大的二号爆炸事件;34.11s后又发生了最强的三号爆炸事件;86.33s再一次发生了能量较弱的四号爆炸事件,其中二号与三号爆炸事件相距65~70m,二号与四号事件相距160~170m。此外,通过选用爆破、矿塌、核爆和天然地震等不同类型事件的波形数据,从时间域和频率域分别对这些事件进行对比分析,发现其震相特征表现出明显差异。  相似文献   

Full moment tensor inversion constrained by double-couple focal mechanism for induced seismicity*          下载免费PDF全文

Yuyang Tan  Haijiang Zhang  Junlun Li  Chen Yin  Furong Wu 《地震科学（英文版）》2020,33(4):177-193

In this study, we propose a new method to determine full moment tensor solution for induced seismicity. This method generalizes the full waveform matching algorithm we have developed to determine the double-couple (DC) focal mechanism based on the neighbourhood algorithm. One major difference between the new method and the former one is that we adopt a new misfit function to constrain the candidate moment tensor solutions with respect to a reference DC solution in addition to other misfit terms characterizing the waveform matching. Through synthetic tests using a real passive seismic survey geometry, the results show the new constraint can help better recover the DC components of inverted moment tensors. We further investigate how errors in the velocity model and source location affect the moment tensor solution. The synthetic test results indicate that the constrained inversion is robust in recovering both the DC and non-DC components. We also test the proposed method on several real induced events in an oil/gas field in Oman using the same observation system as synthetic tests. While it is found that the full moment tensor solutions without using the DC constraints have much larger non-DC components than solutions with the DC constraints, both solutions are able to fit the observed waveforms at similar levels. The synthetic and real test results suggest the proposed DC constrained inversion method can reliably retrieve full moment tensor solutions for the induced seismicity.  相似文献   

A New Retracking Technique for Brown Peaky Altimetric Waveforms     

Fukai Peng 《Marine Geodesy》2018,41(2):99-125

A new Brown-Peaky (BP) retracker has been developed for peaky waveforms that usually appear within ～10 km to the coastline. The main feature of the BP is that it fits peaky waveforms using the Brown model without introducing a peak function. The retracking strategy first detects the peak location and width of a waveform using an adaptive peak detection method, and then estimates retracking parameters using a weighted least squares (WLS) estimator. The WLS assigns a downsized weight to corrupted waveform gates, but an equal weight to other normal waveform gates. The BP retracker has been applied to 4-year Jason-1 waveform (2002–2006) in two Australian coastal zones. The results retracked by BP, MLE4 and ALES retrackers have been validated against tide-gauge observations located at Burnie, Lorne and Broome. The comparison results show that three retrackers have similar performance over open oceans with the correlation coefficient (～0.7) and RMSE (～13 cm) between altimetric and tide-gauge sea levels for distance >7 km offshore. The main improvement of BP retracker occurs for distance ≤7 km to the coastline, where validation results indicate that data retracked by BP are more accurate (15–21 cm) than those by ALES (16–24 cm) and MLE4 (19–37 cm).  相似文献   

2017年6月3日阿拉善左旗5.0级地震震源深度测定   总被引：1，自引：1，他引：0  

郝美仙  宋晓燕  徐岩  翟浩 《地震地磁观测与研究》2018,39(2):18-24

2017年6月3日18时11分内蒙古阿拉善左旗（37.99° N，103.56° E）发生5.0级地震，利用近震深度震相sPL测定法、CAP波形反演法、sPn与Pn震相走时差法，进行震源深度精确测定。研究结果表明，3种方法测得的该地震震源深度基本一致，分布范围为8.5—11 km，表明该地震发生在上地壳。  相似文献   

GEODETIC AND TELESEISMIC CONSTRAINTS ON SLIP DISTRIBUTION OF 2015 M_W6.4 PISHAN EARTHQUAKE          下载免费PDF全文

CHEN Yun-guo  HE Ping  DING Kai-hua  LI Shui-ping  WANG Qi 《地震地质》2019,41(1):137-149

On July 3^rd, 2015, a M_W6.4 earthquake occurred on Pishan County, Xinjiang, located in the front of western Kunlun thrust belt, which is the largest earthquake(M_W6.0~7.0)in the past 40 years in this region. In this study, we collected both the near-filed geodetic coseismic deformation observations including 4 GPS sites and one high-resolution ALOS-2 InSAR imagery, and far-field teleseismic P waveforms from 25 stations provided by IRIS/USGS, to invert the fault parameters(strike and dip)and coseismic rupture model of 2015 M_W6.4 Pishan earthquake. Using the finite fault theory, a non-linear simulated annealing algorithm was employed to resolve our joint inversion problem. The strike (120°~130°) and dip angle(35°~40°)of optimal models are different from that of some previous studies, and the dip change is strongly constrained by combined data than that of strike. In fixing the geometric parameters of optimal fault model, we also considered data weight(5)(geodetic data/teleseismic P waveforms)and constrained weight from moment and smooth factor(2.5). Clearly, our results indicate that the slip distribution mainly concentrates in the depth range from 9 to 16km and a length range of 20km along the strike direction, which is similar to the spatial distribution of the relocated aftershocks. The maximum slip is~95cm. The seismic moment release is 5.45×10¹⁸N·m, corresponding to M_W6.42. Compared with the single data set, geodetic data or teleseismic waveform, our joint inversion model could simultaneously constrain the seismic moment and slip distribution well, thus avoiding effectively a lower-resolution rupture distribution determined by teleseismic-only inversion and a bias released moment estimated by the geodetic-only inversion. Importantly, we should consider both the near-field geodetic data and far-field teleseismic data in retrieving the rupture model for accurately describing the seismogenic structure of active fault in western Kunlun region.  相似文献   

基于三维应变格林函数反演中小震震源机制          下载免费PDF全文

周立  林强  范涛 《地震工程学报》2019,41(6):1553-1559

随着复杂速度结构反演的发展和高性能计算能力的提升,基于高精度3D介质模型计算格林函数反演震源机制更具可行性。中小地震因具有更好的覆盖和近似点源效应,在区域结构成像中有着广泛的应用。基于波形类的反演方法如波动方程层析成像\,全波形反演都需要震源机制解,而传统的震源机制反演方法不能很好地应用于中小地震。采用有限差分法构建应变格林张量(Strain Green Tensor,SGT)数据库,将合成波形和实际波形按震相截窗并滤波到不同的频带范围,先通过最小化互相关走时差来进行震源重定位,再通过最小化波形残差反演震源机制。通过合成数据测试验证方法的正确性,随后将该方法应用于青藏高原东部边缘龙门山地区,反演一系列M_W3.4～5.7的中小地震震源机制。由于应变格林张量数据库可预先构建,该方法可以应用于(近)实时震源机制解反演。  相似文献   

Kelvin-Voigt黏弹性介质井孔声场有限差分数值模拟与波形特征     

岳崇旺  王祝文 《吉林大学学报(地球科学版)》2021,51(4):1268-1275

岩石介质具有黏滞性,黏弹性介质模型相对于弹性介质模型更为接近岩石介质的真实情况。根据Kelvin-Voigt黏弹性单元体模型本构关系,推导了柱坐标系下各向同性黏弹性介质时间域交错网格有限差分方程,进行了黏弹性介质井孔声场的数值模拟。模拟结果表明：品质因子和声源中心频率对黏弹性介质中的井内外声场均有影响：井外声场和井内声场的衰减均随品质因子的增大而减小,井外声波和井内反射波振幅随之增大;井外声场的衰减随声源中心频率的增大而减小,井外声波振幅随之增大,井内声场的衰减随声源中心频率的增大而增大,井内反射波振幅随之减小。  相似文献   

一般地形大光斑激光测高回波模拟研究   总被引：1，自引：0，他引：1  

潘浩  李国元  王华斌  谭天亚  王伶俐 《地理信息世界》2015,(2)

国内对基于陆地模型的地表回波仿真的研究较多,主要分析了三种特定的地表模型:平面、阶梯、斜坡地形,取得了不错的进展,但是却不具有一般性。针对这种情况,本文从一般性地表模型出发,根据实际的地形三维离散点,用Delaunay三角形剖分拟合出地表模型,用剖分后的三角面片返回的能量代表整个地表返回的能量,拟合出回波波形。通过和GLAS系统获取的相同区域的实际回波波形进行相关性比较,结果发现两者具有很好的相关性,验证了算法的正确性。文章结论为后续继续深入开展激光大光斑内精细地形信息分析、激光测高数据与光学影像复合处理提供了理论基础,为发展我国自主的星载激光测高卫星的有关指标论证提供参考。  相似文献   

大光斑波形数据在土地覆盖分类的适用性分析     

马利群  李理  刘俊杰  孙九林  秦奋 《测绘科学》2021,46(3):80-86,95

针对GLAS地学激光测高系统是冰、云和陆地高程卫星(ICESat)的唯一监测工具,能够记录地表光斑内的地物信息,是否能应用于黄土高原土地覆盖分类的问题进行了研究。利用粒子群和最小二乘法相结合的方法对GLAS波形数据进行高斯分解,获取高斯波个数、波形总能量、波形信号起始和信号结束位置4个波形参数;基于波形自动分类方法对黄土高原水体、森林、城市用地、其他地类(裸地、低矮植被等)进行分类。通过基于覆盖相同研究区域的30 m地表覆盖数据(Globe Land30),验证分类的准确性。结果表明,GLAS大光斑波形数据对黄土高原的4种地类能够很好地进行区分,总分类精度高达87.68%,Kappa系数为65.79%。研究表明,GLAS波形数据可以作为获取土地覆盖信息的有效数据源,为研究黄土高原土地覆盖变化提供更丰富的数据支持。  相似文献   

利用地震属性解释煤层冲刷带   总被引：1，自引：0，他引：1  

崔大尉  王一  田庆路  刘最亮  齐振洪 《物探与化探》2011,35(2):234-237

把地震属性技术和地震相分析技术应用于煤层冲刷带的解释工作中。首先从煤层反射波中提取了多种地震属性;然后分析对比地震属性与煤层冲刷带的响应特征;最后利用响应特征明显的地震属性对煤层冲刷带进行了综合解释,确定了煤层冲刷带的范围。与传统钻探解释方法相比,地震属性方法能够更准确地圈定煤层冲刷带的边界。  相似文献