河津4.8级地震前山西临汾台倾斜前驱波特征分析

采用临汾台SSQ-2I型石英摆和VP型宽带垂直摆倾斜仪观测资料,运用原始形态曲线方法,对2010年1月24日山西河津4.8级地震前观测曲线进行分析.结果表明:在震前两种观测手段都记录到明显的前驱波,其形态特征与岩石力学中的粘滑事件非常相似,应是此次地震前显著的短临异常信息,同时给出了产生慢粘滑现象的机理解释.     

基于高光谱数据的气象卫星成像仪红外通道模拟仿真

采用基于光谱匹配的计算方法开展红外通道模拟仿真,该方法利用高光谱大气探测仪的实际观测数据来模拟气象卫星成像仪红外通道观测目标亮温.利用高光谱大气探测仪(IASI)的实际观测数据,进行了2010年2月14日12:57(UTC)、2010年2月15日00:57(UTC)、2010年5月2日12:57(UTC)MTSAT-1R卫星成像仪(JAMI)红外通道的模拟仿真.结果显示:JAMI 4个红外通道的模拟亮温与观测亮温偏差平均值的绝对值都小于1K,模拟亮温与观测亮温的相关系数都大于0.93,表明这种基于高光谱数据的方法可用于气象卫星成像仪红外通道的模拟仿真.进而利用IASI的观测数据进行了 2010年11月6个时刻FY-2E卫星成像仪(VISSR)红外通道的模拟仿真,并将通道模拟数据与GSICS定标的观测数据以及与业务定标的观测数据相比,结果表明:2010年11月期间,FY-2E卫星成像仪IR2、IR3、IR4通道的GSICS定标比业务定标有明显的改进.     

基于GIS平台的宽频带地震数据库

宽频带地震数据库是中国岩石圈三维结构数据库的子库之一.底层库为支持客户/服务器方式的SQL SERVER数据库;基于平台,管理系统用Visual Basic 6.0编程,使用MapObjects控件和ADO技术,实现了属性与空间双向查询、台站和震源两种途经浏览地震记录的波形以及元数据、属性数据、原始记录数据的查询一体化管理和可视化操作.     

用于陆上宽频地震采集的设备及应用实例

宽频带、宽方位、高密度地震数据采集是近年地震勘探的重要发展方向,随着现代电子设备的可靠性大幅度提高,使得\     

中美青藏高原数字宽频带地震观测

1991年7月至1992年7月,中美合作在青藏高原进行了天然地震观测。布设了由11个台站组成的台阵,其中7个台站由北至南分布在青藏公路格尔木至拉萨段沿线,2个分别在其两侧,另外2个在青藏高原东部。此台阵使用REF TEK 72A-02记录器和宽频带STS-2地震计,进行事件触发及连续记录。此次观测为在青藏高原内采集地震数据提供了极好的机会。     

Observations on the leader-return stroke of cloud-to-ground lightning with the broadband interferometer

Radio frequency observations of cloud-to-ground lightning (CG) were made in 1999 in Guangdong Province with the broadband lightning interferometer. In this paper, radiation source locations and electric field waveforms are analyzed for different types of breakdown events, including the preliminary breakdown of in-cloud activities, the stepped leaders of initial strokes to ground and activities during and following return strokes. It is shown that the structure and development of lightning discharges and associated breakdown processes can be reconstructed by using this new type of lightning radiation source location system. The detectable radiation of lightning was primarily produced by the negative breakdown process. The channel was concentrated with few branches during the preliminary breakdown stage of CG lightning flashes. The radiation sources appeared generally at the tip of the channel. During the late period of the stepped leader, the radiation sources were dispersed with branches extended away from the main channel. The radiation sources were in a certain length segment of the channel and the altitude of the segment descended along with the propagation of the leader to the ground. During the preliminary breakdown and the stepped leader of initial strokes to the ground, a sequence of fast negative streamers were observed to start continually from or farther away the lightning-initiated region and propagate along the developed leader channel, which may supply negative charge that assisted the leader’s development. The progression speed of fast negative streamers was about ten times faster than the average speed of lightning channel.     

新的震级国家标准在2018年陕西宁强MS 5.3地震震源参数测定中的应用

利用国家测震台网记录到的2018年9月12日陕西宁强M_S 5.3地震的波形数据,使用新震级国标计算了此次地震宽频带面波震级M_(S(BB)),利用CAP波形反演方法得到震源机制解及矩震级M_W。结果显示:利用50个宽频带测震台站的波形数据测得此次地震的M_(S(BB))为5.0,与GCMT测定的M_S震级一致;由CAP方法反演得到的最佳双力偶参数为节面Ⅰ:走向169°/倾角81°/滑动角9°,节面Ⅱ:走向78°/倾角81°/滑动角171°;矩震级M_W为5.0,与USGS公布的结果较一致,与GCMT公布的结果仅差0.1。研究认为,此次地震震级应为5.0左右,在日常地震速报中可将M_W作为首选发布震级;而对于中强地震,M_(S(BB))震级相较于M_S震级作为发布震级更为合理。     

山西临汾台宽频带倾斜仪映震能力浅析

对山西临汾台VP型宽频带倾斜仪观测资料处理发现,与同台观测的普通倾斜仪相比,该仪器灵敏度高,记录的同震阶变幅度远大于普通形变倾斜仪;该仪器映震能力强,在2010年河津M4．8地震、洪洞M3．6地震、2009年陕西高陵M4．4地震等几次地震前记录到了明显的短期、甚至短临异常变化特征,尤其是在河津地震前更是出现了原始曲线形态、潮汐因子、加卸载响应比等多项丰富的异常信息,说明该仪器对山西带南部地震有较好的映震能力,可为今后分析本区及周边地震活动提供判定依据。     

新疆阿勒泰驼峰山地震台水管倾斜、洞体应变观测异常核实

2013年以来,阿勒泰驼峰山地震台水管倾斜、洞体应变观测值同步趋势性变化,经核实,将其作为学科的A类趋势性异常进行跟踪。在该趋势性异常的背景下,伸缩仪于2018年10月20日起,水管倾斜仪11月24日起,NS分量出现不明原因的转向异常现象。针对该异常变化,于2019年1月1日开展异常核实,认为:①水管倾斜仪工作稳定,观测数据真实可靠;②2018年10月以来水管倾斜仪、伸缩仪观测数据的快速变化与气象要素基本无关,可能与驼峰山台正南方1.1 km处阿勒泰地区检察院对面酒店地下停车场土石方挖倔有较大关系。     

Differences in the Crustal and Uppermost Mantle Structure of the Bohemian Massif from Teleseismic Receiver Functions

A target of our study was the Bohemian Massif in Central Europe that was emplaced during the Variscan orogeny. We used teleseismic records from ten broadband stations lying within and around the massif. Different techniques of receiver function interpretation were applied, including 1-D inversion of R- and Q-components, forward modelling of V _s velocity, and simultaneous determination of Moho depth and Poissons ratio in the crust. These results provide new, independent information about the distribution of S wave velocity down to about 60 km depth. In the area of Bohemian Massif, the crustal thickness varies from 29 km in the NW to 40 km in the SE. A relatively simple velocity structure with gradually increasing velocities in the crust and uppermost mantle is observed in the eastern part of the Bohemian Massif. The western part of the massif is characterized by more complicated structure with low S wave velocities in the upper crust, as well as in the uppermost mantle. This could be related to tectono-magmatic activity in the Eger rift that started in the uppermost Cretaceous and was active in the West Bohemia-Vogland area till the late Cenozoic.