Rapid report of the 8 January 2022 ​MS 6.9 Menyuan earthquake,Qinghai, China     

Hongfeng Yang  Dun Wang  Rumeng Guo  Mengyu Xie  Yang Zang  Yue Wang  Qiang Yao  Chuang Cheng  Yanru An  Yingying Zhang 《地震研究进展（英文）》2022,2(1):100113

The M_S 6.9 Menyuan earthquake in Qinghai Province, west China is the largest earthquake by far in 2022. The earthquake occurs in a tectonically active region, with a background b-value of 0.87 within 100 ?km of the epicenter that we derived from the unified catalog produced by China Earthquake Networks Center since late 2008. Field surveys have revealed surface ruptures extending 22 ?km along strike, with a maximum ground displacement of 2.1 ?m. We construct a finite fault model with constraints from InSAR observations, which showed multiple fault segments during the Menyuan earthquake. The major slip asperity is confined within 10 ?km at depth, with the maximum slip of 3.5 ?m. Near real-time back-projection results of coseismic radiation indicate a northwest propagating rupture that lasted for ～10 ?s. Intensity estimates from the back-projection results show up to a Mercalli scale of IX near the ruptured area, consistent with instrumental measurements and the observations from the field surveys. Aftershock locations (up to January 21, 2022) exhibit two segments, extending to ～20 ?km in depth. The largest one reaches M_S 5.3, locating near the eastern end of the aftershock zone. Although the location and the approximate magnitude of the mainshock had been indicated by previous studies based on paleoearthquake records and seismic gap, as well as estimated stressing rate on faults, significant surface-breaching rupture leads to severe damage of the high-speed railway system, which poses a challenge in accurately assessing earthquake hazards and risks, and thus demands further investigations of the rupture behaviors for crustal earthquakes.  相似文献   

Temporal evolution of the focal mechanism consistency of the 2021 Yangbi MS 6.4 earthquake sequence in Yunnan     

Xiaobin Li  Mingpei Jin  Ya Huang  Wenjian Cha  Jun Wang  Sihai Li 《地震研究进展（英文）》2022,2(2):100061

Using the Cut And Paste (CAP) method, we invert the focal mechanism of 38 moderate earthquakes (M_S ≥ 3.0) recorded by Yunnan seismic network and analyze the corresponding focal mechanism consistency based on the minimum spatial rotation angle. Our results indicate that the M_S 6.4 mainshock is induced by a lateral strike slip fault (with a rake angle of ～ ?165°) and a little normal-faulting component event along a nearly vertical plane (dipping angle～ 79° and strike ～138°). Combining our results with high resolution catalog, we argue that the seismogenic fault of this earthquake sequence is a secondary fault western to the major Weixi-Qiaohou-Weishan fault. The focal mechanism evolution can be divided into three periods. During the first period, the foreshock sequence, the focal mechanism consistency is the highest (KA<36°); during the second period which is shortly after the mainshock, the focal mechanism shows strong variation with KA ranging from 8° to 110°; during the third period, the seismicity becomes weak and the focal mechanism of the earthquakes becomes more consistent than the second period (18°<KA<73°). We suggest that the KA, to some extent, represents the coherence between local tectonic stress regime and the stress state of each individual earthquake. Furthermore, high focal mechanism consistency and high linearity of seismic distribution may serve as indicators for the identification of foreshock sequence.  相似文献   

基于气枪震源信号的云南漾濞M_S6.4地震前后波速变化     

苏金波  杨微  李孝宾  王伟涛  杨军  陈颐 《地球物理学报》2022,65(2):649-662

本文基于宾川气枪地震信号发射台激发的地震波信号,利用线性叠加和时频域相位加权叠加方法提高信噪比,通过反褶积、插值拟合和波形互相关等方法,获得2021年漾濞M;6.4地震前后气枪震源初至波信号走时变化特征.结果表明两种叠加方法得到的走时变化趋势基本一致,在沿发震断裂带附近的3个台站观测到的初至波走时延迟为7.3~14.4 ms,在射线路径上平均波速降低了0.08%~0.12%,距离震中位置较远的台站走时延迟为2~6 ms.分析认为,观测到的走时变化主要是漾濞M;6.4地震引起强地面运动造成浅层介质疏松、同震破裂导致震源区地下介质裂隙增加和地下流体侵入等共同作用造成,相关研究成果有助于加深和促进对此次地震震源物理过程的认识和了解.  相似文献   

南海海洋地磁固定观测站建设初步研究     

魏巍  马媛  汤民强  陈坤  彭聪  王伟平  殷征欣  李正元 《海洋技术学报》2019,38(5)

为填补我国海洋地磁固定观测的空白,支撑科学研究、防灾减灾、海洋资源开发,维护国家的海洋权益和履行我国在南海海域负有的国际责任,急需在南海建设岛礁和海底地磁固定观测站。通过初步分析国外海洋地磁观测站案例、南海岛礁基础设施现状以及海底观测网计划实施情况,认为南海海洋地磁固定观测站建设的条件已经成熟。文中给出了合理空间布局、分步实施、因地制宜及智能化观测的建议。  相似文献   

《震灾防御技术》第6卷(2011年)总目录     

《震灾防御技术》2011,6(4):478-480

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新时期防震减灾宣传教育工作的新思想     

袁志祥  李娟  段锋  张芝霞  李晶 《高原地震》2011,23(4):61-64

对当前防震减灾宣传教育工作的现状进行了分析,针对其存在的问题,提出了防震减灾宣教工作的新思想：把防震减灾宣传教育工作纳入到国家国民教育体系,针对不同的施教对象,有计划、有目的的制定教育计划、编写系列教学读本,通过系统教育,提高国民的防震减灾意识和防灾避险能力,达到最大限度减轻地震灾害的目的。  相似文献   

宁夏及邻区地震活动能量场时空变化特征     

罗国富  屠泓为  许晓庆  马禾青  杨明芝 《高原地震》2011,23(3):13-18

运用随机函数理论,将宁夏及邻区地震活动能量场看作时间和空间的随机函数,用自然正交函数展开方法,系统研究宁夏及邻区主要典型能量场的时间权重系数变化曲线以及典型能量场的空间等值线图。结果发现,目标曲线较大幅度的升、降变化预示了可能发生中强地震的时间段,而等值线图的高值变化（危险区）对应了可能发生中强地震的区域。  相似文献   

日本海域9.0级地震的深刻启示与防灾减灾对策   总被引：1，自引：0，他引：1  

彭忠伟 《高原地震》2011,23(3):63-66

从日本成功的防震减灾经验中受到启示,通过详细分析日本的救灾体系、防灾减灾教育、抗震标准、灾区人口密度和应对福岛核电站问题的相关措施,提出目前我国在这些方面存在的主要问题及应对策略。  相似文献   

GM4磁通门磁力仪的供电设备对观测数据的影响     

张锦玲  陈俊  孙鸿博  邓娜  李西京  汪继林  李雪华 《高原地震》2011,23(4):48-51

通过对我国GM4磁通门磁力仪使用的各种电源设备所产出的观测数据动态曲线的对比研究,认为电源设备对观测数据的影响不容忽视,市电结合UPS方式是最为合适的供电选择。  相似文献   

New friends in new places: Network formation during the migration process among Poles in the UK   总被引：1，自引：0，他引：1  

Nick Gill  Paula Bialski 《Geoforum》2011,42(2):241-249

This paper contributes to on-going work that seeks to understand the dynamic nature of immigrant social network formation. We explore three propositions, derived from the literature, that might be expected to characterise the ways in which migrant associational ties evolve during and immediately after arrival in their destination country. Evidence is drawn from 42 interviews conducted between January and December 2008 with predominantly Polish migrants to the UK (28) as well as domestic service providers (14). In agreement with the existing literature on immigrant social network formation we find that weak associational ties between migrants are locally dense and rapidly formed. More surprisingly, we also find that the Poles in our sample from lower socio-economic groups tended to rely heavily upon weak associational ties while higher socio-economic group Poles tended to rely on associations made through their employing institutions. This illustrates the importance of socio-economic status in framing co-ethnic migrant network formation. This is significant because we also find that weak associational ties are not unambiguously beneficial to lower socio-economic group migrants who tend to (have to be) more compromising about, and therefore more compromised by, the social ‘friendships’ that result.  相似文献