Conjugate ruptures and seismotectonic implications of the 2019 Mindanao earthquake sequence inferred from Sentinel-1 InSAR data

In 2019, four strong earthquakes of Mw>6.4 occurred successively in Mindanao, Philippines. Based on the reports from the USGS and PHIVOLCS, these earthquakes were dominated by strike-slip ruptures. Whether these earthquakes are temporally and spatially related remained unknown. We characterized the coseismic displacement fields during the earthquake sequence using an InSAR technique with Sentinel-1 SAR data. The InSAR deformation measurements convincingly reveal that the four earthquakes produced distinct coseismic displacement patterns. We estimated the source parameters of the earthquakes with a two-step inversion strategy. The optimal model suggests that the earthquake sequence resulted from the reactivation of a conjugate fault structure that involves two nearly vertical left-lateral strike-slip faults and two high-angle right-lateral strike-slip faults. We calculated Coulomb stress changes from the earthquake sequence, suggesting that the previous strong earthquakes had significant stress-encouraging effects on the following events. The regional velocities based on the GPS analysis suggest that the formation of this conjugate structure is mainly due to the westward movement of the subducting Philippine Sea Plate. This earthquake sequence provides a seismotectonic background for subsequent strong earthquakes and helps to better understand the formation mechanisms and seismotectonic implications of conjugate structure rupturing.     

浅谈设备管理信息系统开发项目风险管理

由于信息技术的快速发展和开发工具的日趋成熟,影响管理信息系统开发成功的瓶颈已不再是以技术为主的问题,而更多的是以人为主的风险管理问题。本文主要从风险识别与评估、风险应对与监控、风险回顾与改进这四个方面,阐述了北京市测绘设计研究院设备管理信息系统开发项目的风险管理经验,证实了准确识别和评估项目所面临的风险并进行有效应对和监控,是提高项目成功率的有效手段。     

红河断裂带闭锁程度和滑动亏损分布特征研究

利用1999~2013年青藏高原东南缘的GPS速度场观测数据,采用DEFNODE程序反演红河断裂带走滑速率、三维闭锁程度和滑动亏损分布。反演结果表明:红河断裂带北、中、南段右旋走滑速率分别约为(5.9±1.2)mm/a,(4.8±0.6)mm/a和(4.3±0.4)mm/a,在地表以下6km的闭锁程度分别为0.43,0.22和0.25,其滑动亏损速率分别为3.3mm/a,2.6mm/a和2.3mm/a,红河断裂带闭锁程度和应变积累程度都比较低,与近年来红河断裂带整体活动微弱的现状相吻合。     

小江断裂带地壳运动特征及地震危险性研究

利用1999~2013年间川滇地区的GPS速度场观测数据和块体模型研究小江断裂带地壳运动特征及地震危险性。结果表明:小江断裂带闭锁程度较高,应变量积累较大,在地表以下6km的闭锁程度约为0.94,滑动亏损速率约为(9.2±0.4)mm/a,整条断裂带左旋走滑速率约为(10.8~12.1)mm/a。结合小江断裂带上的历史地震数据估算,小江断裂带未来地震最大震级为7.3级,与近年来断裂带活动较为活跃相吻合。     

多源遥感数据综合解译鄂尔多斯盆地杭锦旗地区地质构造

利用多源遥感数据假彩色合成、融合及纹理分析等增强处理方法提取研究区构造信息,进而对研究区进行综合解译;通过分析水系、色调、纹理、地貌及岩性等特征,判断出杭锦旗地区存在一小一大、内外相套的2个环形构造,发育的北西向、北东向2组共轭断层和一组北北西向断层,与环形构造相互构架,构成研究区特殊的构造体系。经分析预测,这些构造是受周边南北向构造应力共同挤压而形成。     

利用断层自动剖分技术的2008年青海大柴旦Mw6．3级地震InSAR反演研究

2008-11-10青海大柴旦地区发生了Mw6．3级地震,其发震断层位于青藏高原东北缘的大柴旦一宗务隆山断裂带。利用欧空局Envisat／ASAR卫星雷达影像数据,采用二通差分干涉技术获得了地震的同震地表形变场,基于1D协方差函数估计InSAR同震形变场的中误差为0．52cm,方差一协方差衰减距离为5．9km。在此基础上,采用弹性半空间矩形位错模型进行断层几何参数反演,并利用断层自动剖分技术确定了地震的最佳同震滑动分布模型。结果表明,该地震的震源机制解为走向107．19°,倾角56．57°,以逆冲为主兼具少量右旋走滑分量;滑动分布主要发生在10-20km深度范围内,最大滑动量为0．51m,释放的能量为4．3×10^18Nm。     

含交叉断层的复杂地质体3维建模算法研究

在矿井生产中,出现交叉断层的区域往往是地质构造非常复杂的地方,也是危险高发的区域.对含交叉断层的3维地质建模的算法进行了研究.其主要思想是分别建立岩层和断层的TIN模型,以断层交线作为约束条件,进行带约束三角剖分,从而建立起交叉断层模型.这将有利于矿山的工程管理,减少危险的发生,作为后续采矿生产的依据.     

软件模块故障倾向预测方法研究

研究了在区分故障严重程度下的软件模块故障倾向预测方法,将故障分为高严重程度和低严重程度两种类型,用统计分析和机器学习方法分析静态代码度量与故障倾向之间的关系。以公开和私有两种类型的失效数据集作为实验数据,分析发现,故障的严重程度影响预测性能,预测不同严重程度的故障需要选择不同的度量和分类模型,预测低严重程度故障的性能好于预测高严重程度故障的性能。     

Palaeoseismic records in lacustrine sediments—A case study of the Daqingshan piedmont fault and Hasuhai Lake in Inner Mongolia,China

As a traditional method for palaeoseismic studies, trenching can be combined with dating techniques to identify palaeoseismic events and the earthquake recurrence interval. However, when using trenches to study palaeoearthquakes, factors such as the active tectonic background of the earthquake‐caused structure, the lithology on both sides of the fault, the geomorphology location and type and the samples and methods for dating will affect the location of the trench. Thus, trenches should be carefully selected and used to identify the impact of ancient earthquakes. The results have substantial uncertainties and limitations. In recent years, scholars have made considerable progress in using other methods to reveal the palaeoseismic information of faults. Moreover, the history of fault activity may have been recorded in the lacustrine sediment adjacent to the fault. Hasuhai Lake is adjacent to the middle segment of the Daqingshan piedmont fault in Inner Mongolia. Since the Holocene, the region has experienced a temperate continental semi‐arid climate with little interference, and Hasuhai Lake and peripheral waters present weak hydrodynamic conditions that provide an ideal location for the study of palaeoseismic records in lacustrine sediments. Sediment samples and samples for dating were collected from three trenches excavated on the periphery of the Hasuhai Lake. Their variations in grain size and magnetic susceptibility revealed that wind and flowing water jointly produced the sedimentary conditions of Hasuhai sediments. The ¹⁴C dating results and variations in the grain size distribution, grain size components and magnetic susceptibility of sediments caused by seismic events obtained in this study were compared with those caused by a series of palaeoseismic events at the middle segment of the Daqingshan piedmont fault reported by previous studies using trenches, knickpoints and palaeosol records. The results identified seven palaeoseismic events recorded near Hasuhai Lake since 12,000 years. The combined use of lacustrine sediment variation characteristics and dating techniques is an effective method for studying palaeoseismic events.     

浑江市幅区域化探异常遥感评价筛选研究

本文介绍了根据国家计委和地矿部的要求,应用遥感地质方法,即主要通过航卫片解译,结合本区已有地质矿产分布和物化探资料的综合分析,对吉林省浑江市幅区域化探异常进行遥感评价、筛选研究的概况。文中主要阐述了区内金、多金属矿成矿地质特征,论述了断裂构造和环状构造与金、多金属矿及化探异常的关系,简介了区域化探异常遥感评价筛选和野外验证结果以及圈定的若干找矿靶区的情况。