Microearthquake Detection and Its Tectonic Implications in the Eastern Segment of the East Kunlun Fault Zone
-
摘要: 本文整理了一套包括微震检测、地震去噪、震相拾取和地震定位的构建高精度地震目录数据的处理流程。收集了青海省内东昆仑断裂带东段20个数字地震台站记录的2009—2018年的连续地震数据，并应用该流程进行微震检测、去噪和定位。首先，从台网中心提供的
3198 个地震事件目录中筛选出1200 个信噪比高且震相较为明显的地震事件作为模板事件，利用基于图像处理器加速的模板匹配定位方法（GPU-M&L）进行遗漏地震的检测与识别，然后利用基于神经网络的地震波形去噪方法进行去噪处理，再结合基于深度学习的震相拾取技术和双差定位方法对去噪后的地震事件进行震相拾取和定位。使用GPU-M&L共检测出13318 个地震事件，约为台网地震目录事件数量的4.2倍；去噪后得到7514 个地震事件，约为台网地震目录事件数量的2.3倍，完备震级从台网目录的ML 1.5降低至ML 0.9。定位后共获得7247 个地震事件，精定位结果显示，东昆仑断裂带东段的地震以中小震为主，在空间上呈窄条带状或簇状分布，震源深度的优势分布深度为0～15 km；在101°E附近地震的空间展布发生变化，主要沿阿万仓断裂带向东南展布；在玛沁-玛曲段可能存在地震空区。本研究的微震结果为研究东昆仑断裂带东段地震活动性、发震断层的深部构造等提供了重要的数据基础。Abstract: To comprehensively analyze the seismic activity of the East Kunlun Fault Zone from 2009 to 2018, we developed a procedure encompassing microearthquake detection, seismic denoising, seismic phase picking, and seismic location to construct a seismic catalog. We collected continuous waveforms recorded by 20 stations in the eastern segment of the East Kunlun Fault Zone from January 2009 to December 2018. From the3198 seismic events listed in the China Earthquake Networks Center (CENC) catalog, we selected1200 events with clear seismic phases and high signal-to-noise ratios as template events. Using the Graphics Processing Unit-based Match and Locate (GPU-M&L) method, we detected a total of 13,318 earthquake events, including the template events, which is roughly 4.2 times the number of events in the CENC catalog. Next, we employed the neural network-based seismic waveform denoising technique (DeepDenoiser) to extract seismic signals from the noise. By examining the time-domain and frequency-domain characteristics of noise and seismic signals, we further identified and confirmed 7514 seismic events, approximately 2.3 times the number reported by the CENC. The complete magnitude of the detected catalog decreased from ML 1.5, as given by the CENC, to ML 0.9 in this study. Subsequently, we applied the deep neural network-based seismic arrival-time picking algorithm (PhaseNet) to pick the seismic phases. Finally, using the double-difference localization method (hypoDD), we finely located 7247 events. The results show that earthquakes in the eastern segment of the East Kunlun Fault Zone are linearly distributed or clustered, with focal depths predominantly ranging from 0 to 15 km. East of 101°E, the spatial distribution of earthquakes mainly spreads southeastward along the Awancang Fault Zone. Additionally, our results indicate a possible seismic gap in the Maqin-Maqu segment. This study provides an important database for further research on seismic activity and deep seismogenic faults in the eastern segment of the East Kunlun Fault Zone. -
图 1 研究区域地震事件和台站分布图
Figure 1. The distribution of earthquake events and stations in the study area
图 2 利用GPU-M&L方法检测到的地震事件
Figure 2. An example of earthquake event detection by using GPU-ML
图 3 台网目录事件（黑色圆点）与GPU-M&L检测地震事件（红色圆点）震中分布图
Figure 3. Distributions of events （the black dots）from the catalog and the events （the red dots） detected by GPU-M&L
图 4 台网中心地震目录与GPU-M&L检测结果的地震事件对比
Figure 4. The comparison of magnitude–frequency between the catalogue events and the detected events
图 5 1.58级地震事件波形去噪前后对比
Figure 5. The waveform comparison of a ML 1.58 event before and after denoising
图 6 利用DeepDenoiser对不同台站记录到的同一个地震事件Z分量去噪前后波形对比
Figure 6. The waveform comparison of Z components before and after denoising
图 7 台网中心地震目录与去噪后地震事件震级-数量对比
Figure 7. The magnitude–frequency comparison between the catalogue events and the denoised events
图 8 去噪后目录与原始目录最小完备震级对比
Figure 8. The MC comparison between the original and denoised catalogues
图 10 去噪后的地震事件P波和S波走时曲线
Figure 10. The time-distance curves for P and S waves, as illustrated in the left and right panels respectively
图 11 台网目录事件（灰色圆点）与新目录地震事件（红色圆点）重定位后分布对比
Figure 11. The event distribution given by the CENC catalogue （gray dots） and the relocated catalogue （red dots）
-
邓起东,张培震,冉勇康等,2003. 中国活动构造与地震活动. 地学前缘,10(S1):66−73. doi: 10.3321/j.issn:1005-2321.2003.z1.012Deng Q. D., Zhang P. Z., Ran Y. K., et al., 2003. Active tectonics and earthquake activities in China. Earth Science Frontiers, 10(S1): 66−73. (in Chinese) doi: 10.3321/j.issn:1005-2321.2003.z1.012 李陈侠,徐锡伟,闻学泽等,2011. 东昆仑断裂带中东部地震破裂分段性与走滑运动分解作用. 中国科学:地球科学,41(9):1295−1310. doi: 10.1007/s11430-011-4239-5Li C. X., Xu X. W., Wen X. Z., et al., 2011. Rupture segmentation and slip partitioning of the mid-eastern part of the Kunlun Fault, north Tibetan Plateau. Science China Earth Science, 54(11): 1730−1745. (in Chinese) doi: 10.1007/s11430-011-4239-5 李陈侠,袁道阳,杨虎等,2016. 东昆仑断裂带东段分支断裂−−阿万仓断裂晚第四纪构造活动特征. 地震地质,38(1):44−64. doi: 10.3969/j.issn.0253-4967.2016.01.004Li C. X., Yuan D. Y., Yang H., et al., 2016. The tectonic activity characteristics of Awancang fault in the late quaternary, the sub-strand of the eastern Kunlun fault. Seismology and Geology, 38(1): 44−64. (in Chinese) doi: 10.3969/j.issn.0253-4967.2016.01.004 李海龙,2016. 鲜水河、东昆仑断裂新构造变形研究与对比. 北京:中国地质大学(北京).Li H. L. , 2016. The study on the neotectonic deformation of the Xianshuihe and East Kunlun faults. Beijing: China University of Geosciences (Beijing). (in Chinese) 李璐,王宝善,侯金欣,2017. 模板匹配滤波技术在地震数据处理中的应用. 中国地震,33(1):14−22.Li L. , Wang B. S. , Hou J. X. , 2017. Applications of matched filter technique in seismic data processing. Earthquake Research in China, 2017, 33 (1): 14−22. (in Chinese) 王同利,刘敏,李红谊等,2019. 阿拉善左旗 M S5.8地震前后地震活动性分析和重定位. 地球物理学报,62(6):2038−2047. doi: 10.6038/cjg2019N0024Wang T. L., Liu M., Li H. Y., et al., 2019. Relocation of the aftershock sequence and activity of the M S5.8 Alxa earthquake. Chinese Journal of Geophysics, 62(6): 2038−2047. (in Chinese) doi: 10.6038/cjg2019N0024 闻学泽,张培震,杜方等,2009. 2008年汶川8.0级地震发生的历史与现今地震活动背景. 地球物理学报,52(2):444−454.Wen X. Z., Zhang P. Z., Du F., et al., 2009. The background of historical and modern seismic activities of the occurrence of the 2008 M S8.0 Wenchuan, Sichuan, earthquake. Chinese Journal of Geophysics, 52(2): 444−454. (in Chinese) 徐锡伟,陈文彬,于贵华等,2002. 2001年11月14日昆仑山库赛湖地震( M S8.1)地表破裂带的基本特征. 地震地质,24(1):1−13. doi: 10.3969/j.issn.0253-4967.2002.01.001Xu X. W., Chen W. B., Yu G. H., et al., 2002. Characteristic features of the surface ruptures of the Hoh Sai Hu (Kunlunshan) earthquake ( M S8.1), northern Tibetan Plateau, China. Seismology and Geology, 24(1): 1−13. (in Chinese) doi: 10.3969/j.issn.0253-4967.2002.01.001 张军龙,任金卫,陈长云等,2014. 东昆仑断裂带东部晚更新世以来活动特征及其大地构造意义. 中国科学:地球科学,44(4):654−667. doi: 10.1007/s11430-013-4759-2Zhang J. L., Ren J. W., Chen C Y, et al., 2014. The Late Pleistocene activity of the eastern part of east Kunlun fault zone and its tectonic significance. Science China Earth Sciences, 57(3): 439−453. (in Chinese) doi: 10.1007/s11430-013-4759-2 张淼,2015. 地震定位和检测. 合肥:中国科学技术大学.Zhang M. , 2015. Earthquake location and detection. Hefei: University of Science and Technology of China. (in Chinese) 赵明,唐淋,陈石等,2021. 基于深度学习到时拾取自动构建长宁地震前震目录. 地球物理学报,64(1):54−66. doi: 10.6038/cjg2021O0271Zhao M., Tang L., Chen S., et al., 2021. Machine learning based automatic foreshock catalog building for the 2019 M S6.0 Changning, Sichuan earthquake. Chinese Journal of Geophysics, 64(1): 54−66. (in Chinese) doi: 10.6038/cjg2021O0271 朱艾斓,徐锡伟,周永胜等,2005. 川西地区小震重新定位及其活动构造意义. 地球物理学报,48(3):629−636. doi: 10.3321/j.issn:0001-5733.2005.03.021Zhu A. L., Xu X. W., Zhou Y. S., et al., 2005. Relocation of small earthquakes in western Sichuan, China and its implications for active tectonics. Chinese Journal of Geophysics, 48(3): 629−636. (in Chinese) doi: 10.3321/j.issn:0001-5733.2005.03.021 Allen R., 1982. Automatic phase pickers: their present use and future prospects. Bulletin of the Seismological Society of America, 72(6B): S225−S242. doi: 10.1785/BSSA07206B0225 Bao X. W., Eaton D. W., 2016. Fault activation by hydraulic fracturing in western Canada. Science, 354(6318): 1406−1409. doi: 10.1126/science.aag2583 Chouet B. A., 1996. Long-period volcano seismicity: its source and use in eruption forecasting. Nature, 380(6572): 309−316. doi: 10.1038/380309a0 Ellsworth W. L., 2013. Injection-induced earthquakes. Science, 341(6142): 1225942. doi: 10.1126/science.1225942 Ellsworth W. L., Bulut F., 2018. Nucleation of the 1999 Izmit earthquake by a triggered cascade of foreshocks. Nature Geoscience, 11(7): 531−535. doi: 10.1038/s41561-018-0145-1 Fisk M. D., 2006. Source spectral modeling of regional P/S discriminants at nuclear test sites in China and the former Soviet Union. Bulletin of the Seismological Society of America, 96(6): 2348−2367. doi: 10.1785/0120060023 Gutenberg B., Richter C. F., 1944. Frequency of earthquakes in California. Bulletin of the Seismological Society of America, 34(4): 185−188. doi: 10.1785/BSSA0340040185 Kato A., Obara K., Igarashi T., et al., 2012. Propagation of slow slip leading up to the 2011 MW 9.0 Tohoku-Oki earthquake. Science, 335(6069): 705−708. doi: 10.1126/science.1215141 Liu M., Li H. Y., Peng Z. G., et al., 2019. Spatial-temporal distribution of early aftershocks following the 2016 MS 6.4 Menyuan, Qinghai, China Earthquake. Tectonophysics, 766: 469−479. doi: 10.1016/j.tecto.2019.06.022 Liu M., Li H. Y., Zhang M., et al., 2020. Graphics processing unit-based match and locate (GPU-M&L): an improved match and locate method and its application. Seismological Research Letters, 91(2A): 1019−1029. doi: 10.1785/0220190241 Mogi K., 1979. Two kinds of seismic gaps. Pure and Applied Geophysics, 117(6): 1172−1186. doi: 10.1007/BF00876213 Ross Z. E., Trugman D. T., Hauksson E., et al., 2019. Searching for hidden earthquakes in Southern California. Science, 364(6442): 767−771. doi: 10.1126/science.aaw6888 Shelly D. R., Beroza G. C., Ide S., 2007. Non-volcanic tremor and low-frequency earthquake swarms. Nature, 446(7133): 305−307. doi: 10.1038/nature05666 Tan Y. J., Waldhauser F., Ellsworth W. L., et al., 2021. Machine-learning-based high-resolution earthquake catalog reveals how complex fault structures were activated during the 2016-2017 Central Italy sequence. The Seismic Record, 1(1): 11−19. doi: 10.1785/0320210001 Waldhauser F., Ellsworth W. L., 2000. A double-difference earthquake location algorithm: method and application to the northern Hayward fault, California. Bulletin of the Seismological Society of America, 90(6): 1353−1368. doi: 10.1785/0120000006 Withers M., Aster R., Young C., et al., 1998. A comparison of select trigger algorithms for automated global seismic phase and event detection. Bulletin of the Seismological Society of America, 88(1): 95−106. doi: 10.1785/BSSA0880010095 Wu J., Yao D. D., Meng X. F., et al., 2017. Spatial-temporal evolutions of early aftershocks following the 2013 M W6.6 Lushan earthquake in Sichuan, China. Journal of Geophysical Research: Solid Earth, 122(4): 2873−2889. doi: 10.1002/2016JB013706 Zhao L. F., Xie X. B., Wang W. M., et al., 2008. Regional seismic characteristics of the 9 October 2006 North Korean nuclear test. Bulletin of the Seismological Society of America, 98(6): 2571−2589. doi: 10.1785/0120080128 Zhu W. Q., Mousavi S. M., Beroza G. C., 2019a. Seismic signal denoising and decomposition using deep neural networks. IEEE Transactions on Geoscience and Remote Sensing, 57(11): 9476−9488. doi: 10.1109/TGRS.2019.2926772 Zhu W. Q., Beroza G. C., 2019b. PhaseNet: a deep-neural-network-based seismic arrival-time picking method. Geophysical Journal International, 216(1): 261−273. -
下载:
点击查看大图
计量
- 文章访问数: 61
- HTML全文浏览量: 31
- PDF下载量: 14
- 被引次数: 0
