Real-time discrimination of earthquake foreshocks and aftershocks
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摘要: 一次大地震发生后，公众和决策者首先便会提出一个重要的问题：这是一个主震还是一个即将来临的更大地震的前震。到目前为止，科学家们只能通过对过去历史地震序列的统计给出经验性的结论，通常认为，余震序列会随着时间的推移而逐渐减小，未来发生更大地震的可能性只有百分之几。本文中，我们分析了意大利阿马特里奇-诺尔恰（Amatrice–Norcia）地震和日本熊本（Kumamoto）地震的序列余震平均大小分布，认为在一些情况下，区分一个序列是衰减的余震序列还是正在发展的即将发生更大地震的序列，是有可能的。我们同时提出了一个简单的“交通灯”分级准则来实时评估其对序列后续更大地震的敏感程度，并对58次地震进行了测试，结果显示准确率可达95%。
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图 1 阿马特里奇-诺尔恰序列b值的时空分析
（a） 、 （b）分别为阿马特里奇和诺尔恰地震震源区b值的时间序列。蓝色虚线表示背景b值，灰色垂直虚线表示阿马特里奇MW6.2和诺尔恰MW6.6之间的结果。灰色阴影区域表示结果的不确定度。 （c） 、 （d）为3个不同时段内两个源区的震级-频率关系（不确定性来自Shi和Bolt的结果[29]）。（e）、 （f）分别为不同阶段地震活动分布图和前震之前的b值。 （g） 、 （h）分别为两次地震期间和后续主震之后的b值相对于背景变化
图 2 熊本序列b值的时空分析
（a） 、 （b）分别为MW6.5和MW7.3地震震源区b值的时间序列。蓝色虚线表示背景b值，灰色垂直虚线表示MW6.5和MW7.3之间的结果。灰色阴影区域表示结果的不确定度。 （c） 、 （d）为3个不同时段内两个源区的震级-频率关系（不确定性来自Shi和Bolt的结果[29]）。 （e） 、 （f）分别为不同阶段地震活动分布图和前震之前的b值。 （g） 、 （h）分别为两次地震期间和后续主震之后两周的b值相对于背景变化
图 3 2011年日本9级地震序列的频率-震级分布
（a） MW7.3地震破裂面12 km范围内3个不同阶段内的频率-震级分布（不确定性来自Shi和Bolt的结果[29]）；（b） 包含有MW9.0地震50%破裂面范围内3个阶段内的频度-震级分布
图 4 前震识别交通灯系统
频率震级分布图（a）和b值时间序列（c）在FTLS报警系统的信号示意图。绿色表示正常余震序列，b值增加约20%，后期不会发生更大地震；黄色表示余震序列中b值保持不变或难以确定；红色表示b值显著降低，需要考虑必要的减灾措施； （b）为叠加31个序列给出的参考b值相对背景值的变化水平。黑色垂直虚线表示主震
表 1 图5中显示的b值变化
地震 目录来源 时间 震级(MS) b值变化（%） FTLS信号 Coalinga ANSS 1983-05-02 6.7 125 绿 Morgan Hill ANSS 1984-04-24 6.2 83 红 Round Valley ANSS 1984-11-23 6.1 113 绿 Chalfant Valley ANSS 1986-07-21 6.4 164 绿 Loma Prieta ANSS 1989-10-18 7.0 173 绿 Joshua Tree ANSS 1992-04-23 6.1 115 绿 Landers ANSS 1992-06-28 7.3 124 绿 Eureka Valley ANSS 1993-05-17 6.1 92 黄 Northridge ANSS 1994-01-17 6.7 107 黄 Hector Mine ANSS 1999-10-16 7.1 103 黄 San Simeon ANSS 2003-12-22 6.5 99 黄 Parkfield ANSS 2004-09-28 6.0 136 绿 El Mayor Cucapah ANSS 2010-04-04 7.2 124 绿 Tottori JMA 2000-10-06 7.3 96 黄 Ryukyu JMA 2001-12-18 7.3 191 绿 Chūetsu JMA 2004-10-23 6.8 126 绿 Southern Romoi JMA 2004-12-14 6.1 112 绿 Fukuoka JMA 2005-03-20 7.0 103 黄 Chūetsu Offshore JMA 2007-07-16 6.8 128 绿 Iwate JMA 2006-06-13 7.2 104 黄 Awaji Island JMA 2013-04-12 6.3 150 绿 Nagano JMA 2014-11-22 6.7 105 黄 Kumamoto JMA 2016-04-14 6.5 88 红 Kumamoto JMA 2016-04-15 7.3 138 绿 Fukushima JMA 2016-11-21 7.4 178 绿 L’Aquila Gasperini等[27] 2009-04-06 6.3 139 绿 Amatrice Gasperini等[27] 2016-08-24 6.2 83 红 Norcia Gasperini等[27] 2016-10-30 6.5 116 绿 Denali AEIC 2002-11-03 7.6 145 绿 Tohoku JMA 2011-03-09 7.3 73 红 Tohoku JMA 2011-03-11 9.0 140 绿 
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[1] Jordan T H. Operational earthquake forecasting state of knowledge and guidelines for utilization[J]. Ann. Geophys.,2011,54(4):315-391 [2] Lippiello E,Giacco F,Marzocchi W,et al. Statistical features of foreshocks in instrumental and ETAS catalogs[J]. Pure Appl. Geophys.,2017,174(4):1679-1697 doi: 10.1007/s00024-017-1502-5 [3] Reasenberg P A,Jones L M. California aftershock hazard forecast[J]. Science,1990,247(4940):345-346 doi: 10.1126/science.247.4940.345 [4] Roeloffs E,Goltz J. The California earthquake advisory plan:A history[J]. Seismol. Res. Lett.,2017,88(3):784-797 doi: 10.1785/0220160183 [5] Field E H,Jordan T H,Jones L M,et al. The potential uses of operational earthquake forecasting[J]. Seismol. Res. Lett.,2016,87(2A):313-322 doi: 10.1785/0220150174 [6] Zechar J D,Marzocchi W,Wiemer S. Operational earthquake forecasting in Europe:Progress,despite challenges[J]. Bull. Earthquake Eng.,2016,14(9):2459-2469 doi: 10.1007/s10518-016-9930-7 [7] Ogata Y. Statistical models for earthquake occurrences and residual analysis for point processes[J]. J. Am. Stat. Assoc.,1988,83(401):9-27 doi: 10.1080/01621459.1988.10478560 [8] Ogata Y. Space-time point-process models for earthquake occurrences[J]. Ann. Inst. Stat. Math.,1998,50(2):379-402 doi: 10.1023/A:1003403601725 [9] Gerstenberger M C,Wiemer S,Jones L M,et al. Real-time forecasts of tomorrow’s earthquakes in California[J]. Nature,2005,435(7040):328-331 doi: 10.1038/nature03622 [10] Parsons T,Segou M,Sevilgen V, et al. Stress-based aftershock forecasts made within 24 h postmain shock:Expected north San Francisco Bay area seismicity changes after the 2014 M=6.0 West Napa earthquake[J]. Geophys. Res. Lett.,2014,41(4):8792-8799 doi: 10.1002/2014GL062379 [11] Stein R. Earthquake conversations[J]. Sci. Am.,2003,288(1):72-79 doi: 10.1038/scientificamerican0103-72 [12] Woessner J,Hainzl S,Marzocchi W,et al. A retrospective comparative forecast test on the 1992 Landers sequence[J]. J. Geophys. Res.,2011,116:B05305 [13] van Stiphout T,Wiemer S,Marzocchi W. Are short-term evacuations warranted?Case of the 2009 L’Aquila earthquake[J]. Geophys. Res. Lett.,2010,37(6):L06306 [14] Gulia L,Tormann T,Wiemer S,et al. Short-term probabilistic earthquake risk assessment considering time-dependent b values[J]. Geophys. Res. Lett.,2016,43(3):1100-1108 doi: 10.1002/2015GL066686 [15] Brodsky E E,Lay T. Recognizing foreshocks from the 1 April 2014 Chile earthquake[J]. Science,2014,344(6185):700-702 doi: 10.1126/science.1255202 [16] Bouchon M,Durand V,Marsan D,et al. The long precursory phase of most large interplate earthquakes[J]. Nat. Geosci.,2013,6(4):299-302 doi: 10.1038/ngeo1770 [17] Ellsworth W L,Bulut F. Nucleation of the 1999 Izmit earthquake by a triggered cascade of foreshocks[J]. Nat. Geosci.,2018,11(7):531-535 doi: 10.1038/s41561-018-0145-1 [18] Gutenberg B,Richter C F. Frequency of earthquakes in California[J]. Bull. Seismol. Soc. Amer.,1944,34(4):185-188 [19] Ishimoto M,Iida I. Observations of earthquakes registered with the microseismograph constructed recently[J]. Bull. Earthquake Res. Inst. Univ. Tokyo,1936,17:443-478 [20] Goebel T H W,Schorlemmer D,Becker T W,et al. Acoustic emissions document stress changes over many seismic cycles in stick-slip experiments[J]. Geophys. Res. Lett.,2013,40(10):2049-2054 doi: 10.1002/grl.50507 [21] Amitrano D. Brittle-ductile transition and associated seismicity:Experimental and numerical studies and relationship with the b value[J]. J. Geophys. Res.,2003,108(B1):1-15 [22] Scholz C H. The frequency-magnitude relation of microfracturing in rock and its relation to earthquakes[J]. Bull. Seismol. Soc. Amer.,1968,58(1):399-415 [23] Schorlemmer D,Wiemer S,Wyss M. Variations in earthquake-size distribution across different stress regimes[J]. Nature,2005,437(7058):539-542 doi: 10.1038/nature04094 [24] Gulia L,Rinaldi A P,Tormann T,et al. The effect of a mainshock on the size distribution of the aftershocks[J]. Geophys. Res. Lett.,2018,45(24):13277-13287 [25] Helmstetter A,Kagan Y Y,Jackson D D. Comparison of short-term and time-independent earthquake forecast models for southern California[J]. Bull. Seismol. Soc. Amer.,2006,96(1):90-106 doi: 10.1785/0120050067 [26] Vannucci G,Gasperini P,Lolli B,et al. Fast characterization of sources of recent Italian earthquakes from macroseismic intensities[J]. Tectonophysics,2019,750:70-92 doi: 10.1016/j.tecto.2018.11.002 [27] Gasperini P,Lolli B,Vannucci G. Empirical calibration of local magnitude data sets versus moment magnitude in Italy[J]. Bull. Seismol. Soc. Amer.,2013,103(4):2227-2246 doi: 10.1785/0120120356 [28] Wiemer S,Wyss M. Mapping the frequency-magnitude distribution in asperities:An improved technique to calculate recurrence times? [J]. J. Geophys. Res.,1997,1021(B7):15115-15128 [29] Shi Y,Bolt B A. The standard error of the magnitude-frequency b value[J]. Bull. Seismol. Soc. Amer.,1982,72(5):1677-1687 [30] Japan Meteorological Agency. JMA catalogue[EB/OL]. [2019-02-09]. http://www.data.jma.go.jp/svd/eqev/data/bulletin/index_e.html [31] Earthquake Research Committee. Evaluation of the 2016 Kumamoto Earthquakes （ERC, 2016）[EB/OL]. (2016-05-13)[2019-02-09]. https://www.jishin.go.jp/main/chousa/16may_kumamoto2/index-e.htm [32] Nanjo K Z,Yoshida A. Anomalous decrease in relatively large shocks and increase in the p and b values preceding the April 16,2016,M7.3 earthquake in Kumamoto,Japan[J]. Earth. Planets and Space,2017(1):1-8 [33] Omi T,Ogata Y,Shiomi K, et al. Implementation of a real-time system for automatic aftershock forecasting in Japan[J]. Seismol. Res. Lett.,2019,90(1):242-250 doi: 10.1785/0220180213 [34] Tormann T,Enescu B,Woessner J,et al. Randomness of megathrust earthquakes implied by rapid stress recovery after the Japan earthquake[J]. Nat. Geosci.,2015,8(2):152-158 doi: 10.1038/ngeo2343 [35] Gomber J. Unsettled earthquake nucleation[J]. Nat. Geosci.,2018,11(7):463-464 doi: 10.1038/s41561-018-0149-x [36] Mignan A. The debate on the prognostic value of earthquake foreshocks:A meta-analysis[J]. Sci. Rep.,2014,4:4099 [37] Tape C,Holtkamp S,Silwal V,et al. Earthquake nucleation and fault slip complexity in the lower crust of central Alaska[J]. Nat. Geosci.,2018,11(8):536-541 [38] Okada Y. Internal deformation due to shear and tensile faults in a half-space[J]. Bull. Seismol. Soc. Amer.,1992,82(2):1018-1040 [39] European Commission. A strategy for Europe on nutrition, overweight and obesity related health issues. White paper COM （2007） 279[EB/OL]. [2019-02-09]. https://ec.europa.eu/health/ph_determinants/life_style/nutrition/documents/nutrition_wp_en.pdf [40] Department of Health. Information for a healthy New York: Asthma action plan （New York State Department of Health, 2002）[EB/OL]. [2019-02-09]. www.health.state.ny.us/diseases/asthma/pdf/4850.pdf [41] Bommer J J,Oates S,Cepeda J M,et al. Control of hazard due to seismicity induced by a hot fractured rock geothermal project[J]. Eng. Geol.,2006,83(4):287-306 doi: 10.1016/j.enggeo.2005.11.002 [42] Mignan A,Broccardo M,Wiemer S,et al. Induced seismicity closed-form traffic light system for actuarial decision-making during deep fluid injections[J]. Sci. Rep.,2017,7(1):13607 doi: 10.1038/s41598-017-13585-9 [43] Li Z F,Meier M A,Hauksson E,et al. Machine learning seismic wave discrimination:Application to earthquake early warning[J]. Geophys. Res. Lett.,2018,45(10):4773-4779 doi: 10.1029/2018GL077870 [44] Shelly D R. A 15 year catalog of more than 1 million low-frequency earthquakes:Tracking tremor and slip along the deep San Andreas Fault[J]. J. Geophys. Res.:Solid Earth,2017,122(5):3739-3753 doi: 10.1002/2017JB014047 [45] Jordan T H. Earthquake predictability,brick by brick[J]. Seismol. Res. Lett.,2006,77(1):3-6 doi: 10.1785/gssrl.77.1.3 [46] Schorlemmer D,Werner M J,Marzocchi W,et al. The collaboratory for the study of earthquake predictability:Achievements and priorities[J]. Seismol. Res. Lett.,2018,89(4):1305-1313 doi: 10.1785/0220180053 -
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