433:. In one model of earthquake rupture, the process forms as a cascade, starting with a very small event that triggers a larger one, continuing until the main shock rupture is triggered. However, analysis of some foreshocks has shown that they tend to relieve stress around the fault. In this view, foreshocks and aftershocks are part of the same process. This is supported by an observed relationship between the rate of foreshocks and the rate of aftershocks for an event. In practice, there are two main conflicting theories about foreshocks: earthquake triggering process (described in SOC models and ETAS-like models) and the loading process by aseismic slip (nucleation models). This debate about the prognostic value of foreshocks is well known as Foreshock Hypothesis.
40:
449:
in China, where an evacuation was triggered by an increase in activity. However, most earthquakes lack obvious foreshock patterns and this method has not proven useful, as most small earthquakes are not foreshocks, leading to probable false alarms. Earthquakes along oceanic
412:
The increase in foreshock activity is difficult to quantify for individual earthquakes but becomes apparent when combining the results of many different events. From such combined observations, the increase before the mainshock is observed to be of
393:
Foreshock activity has been detected for about 40% of all moderate to large earthquakes, and about 70% for events of M>7.0. They occur from a matter of minutes to days or even longer before the main shock; for example, the
1237:
593:
1444:
1268:
246:
1604:
1330:
670:
1306:
1213:
1176:
1133:
429:
The observation of foreshocks associated with many earthquakes suggests that they are part of a preparation process prior to
348:
816:
1203:
1123:
508:
454:
do show repeatable foreshock behaviour, allowing the prediction of both the location and timing of such earthquakes.
1085:
406:
1573:
1294:
96:
765:
583:
1622:
1590:
779:
277:
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399:
1448:
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resulting in the mainshock or that the increase is related to a general increase in stress in the region.
1636:
1158:
995:
144:
1608:
1471:
948:
733:
531:
904:
341:
322:
282:
1472:"Foreshock sequences and short-term earthquake predictability on East Pacific Rise transform faults"
1038:
618:
464:
446:
373: – and is related to it in both time and space. The designation of an earthquake as
225:
220:
1238:"Rupture Properties of the Giant Sumatra Earthquake Imaged by Empirical Green's Function Analysis"
1361:
860:
635:
566:
528:
418:
395:
71:
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468:
287:
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111:
91:
86:
81:
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1483:
1399:
1345:
1252:
717:
334:
317:
272:
106:
23:
926:
8:
1664:
1534:"Active faulting in SW Bulgaria: possible surface rupture of the 1904 Struma earthquakes"
882:
172:
49:
1549:
1487:
1403:
1349:
1256:
430:
1507:
1420:
1387:
541:
149:
116:
76:
838:
405:
Some great earthquakes (M>8.0) show no foreshock activity at all, such as the M8.6
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1159:
National
Research Council (U.S.). Committee on the Science of Earthquakes (2003).
1017:
451:
139:
101:
743:
39:
1388:"The debate on the prognostic value of earthquake foreshocks: A meta-analysis"
1658:
974:
1503:
1429:
623:
571:
187:
1295:"Time distribution of immediate foreshocks obtained by a stacking method"
1064:
215:
182:
1495:
1299:
Seismicity patterns, their statistical significance and physical meaning
441:
An increase in seismic activity in an area has been used as a method of
1357:
1264:
970:
692:
382:
366:
297:
177:
66:
31:
1411:
1301:. Reprint from Pageoph Topical Volumes. Birkhäuser. pp. 381–394.
649:
414:
370:
167:
56:
545:
292:
16:
Earthquake that occurs before a mainshock but is of lower magnitude
463:
The strongest recorded mainshock that followed a foreshock is the
645:
385:
is only possible after the full sequence of events has happened.
1469:
1328:
457:
369:
that occurs before a larger seismic event – the
197:
192:
1331:"A Common Origin for Aftershocks, Foreshocks, and Multiplets"
1165:
Living on an Active Earth: Perspectives on
Earthquake Science
795:
597:
1205:
Microearthquake seismology and seismotectonics of South Asia
402:
with a delay of more than two years between the two events.
696:
1447:. The Pacific Northwest Seismic Network. Archived from
1605:"Magnitude 7.3 - NEAR THE EAST COAST OF HONSHU, JAPAN"
1167:. Washington D.C.: National Academies Press. p.
1531:
1470:McGuire, J.J.; Boettcher M.S.; Jordan T.H. (2005).
1329:Felzer, K.R.; Abercrombie R.E.; Ekström G. (2004).
734:
1656:
1338:Bulletin of the Seismological Society of America
1245:Bulletin of the Seismological Society of America
1161:"5. Earthquake Physics and Fault-System Science"
1639:. United States Geological Survey. July 4, 2019
1525:
1297:. In Wyss M., Shimazaki K. & Ito A. (ed.).
417:type. This may either indicate that foreshocks
458:Examples of earthquakes with foreshock events
342:
1532:Meyer, B.; Armijo, R.; Dimitroy, D. (2002).
1121:
349:
335:
1557:
1419:
1125:Encyclopedia of Earthquakes and Volcanoes
532:
671:2004 Indian Ocean earthquake and tsunami
436:
1637:"M 4.0 - 11km SW of Searles Valley, CA"
1197:
1195:
1657:
1463:
1442:
1385:
1235:
1436:
1379:
1322:
1292:
1229:
1201:
1154:
1152:
1574:"El Sismo del 20 de Octubre de 2006"
1286:
1192:
1115:
1128:. Infobase Publishing. p. 89.
13:
1149:
817:2011 TĹŤhoku earthquake and tsunami
445:, most notably in the case of the
398:is regarded as a foreshock of the
14:
1681:
1538:Geophysical Journal International
1559:10.1046/j.0956-540x.2001.01589.x
1443:Ludwin, R. (16 September 2004).
1086:2021 Kermadec Islands earthquake
38:
1629:
1615:
1597:
1583:
1566:
1386:Mignan, A. (14 February 2014).
1122:Gates, A.; Ritchie, D. (2006).
467:, which had a magnitude of 9.5
1:
1108:
682:October 20, 2006 (10 months)
388:
729:January 23, 2007 (3 months)
424:
400:2004 Indian Ocean earthquake
7:
1623:"Informe de sismo sensible"
1591:"Informe de sismo sensible"
996:2019 Ridgecrest earthquakes
766:2007 Aysén Fjord earthquake
632:November 2, 2002 (2 years)
525:April 4, 1904 (23 minutes)
407:1950 India–China earthquake
10:
1686:
1007:December 28, 2020 (1 day)
949:2017 Valparaiso earthquake
247:Coordinating Committee for
1103:: dates are in local time
905:2016 Kumamoto earthquakes
828:March 16, 2014 (15 days)
278:Adams–Williamson equation
1208:. Springer. p. 15.
1050:March 5, 2021 (2 hours)
1039:2020 Petrinja earthquake
916:April 22, 2017 (2 days)
872:April 14, 2016 (2 days)
619:1960 Valdivia earthquake
465:1960 Valdivia earthquake
447:1975 Haicheng earthquake
226:Seismic intensity scales
221:Seismic magnitude scales
1445:"Earthquake Prediction"
861:2014 Iquique earthquake
567:1904 Kresna earthquakes
396:2002 Sumatra earthquake
1607:. USGS. Archived from
780:March 9, 2011 (2 days)
443:predicting earthquakes
288:Earthquake engineering
960:July 4, 2019 (1 day)
580:May 21, 1960 (1 day)
437:Earthquake prediction
311:Earth Sciences Portal
283:Flinn–Engdahl regions
249:Earthquake Prediction
1202:Kayal, J.R. (2008).
718:2007 Peru earthquake
419:cause stress changes
273:Shear wave splitting
1670:Types of earthquake
1550:2002GeoJI.148..246M
1496:10.1038/nature03377
1488:2005Natur.434..457M
1404:2014NatSR...4E4099M
1350:2004BuSSA..94...88F
1257:2007BuSSA..97S.103V
1236:Vallée, M. (2007).
883:Kumamoto Prefecture
173:Epicentral distance
1625:(in Spanish). GUC.
1593:(in Spanish). GUC.
1579:(in Spanish). IGP.
1392:Scientific Reports
1358:10.1785/0120030069
1293:Maeda, K. (1999).
1265:10.1785/0120050616
1022:December 29, 2020
654:December 26, 2004
542:Blagoevgrad region
150:Induced seismicity
97:Remotely triggered
1482:(7032): 457–461.
1412:10.1038/srep04099
1308:978-3-7643-6209-6
1251:(1A): S103–S114.
1215:978-1-4020-8179-8
1178:978-0-309-06562-7
1135:978-0-8160-6302-4
1104:
1096:
1095:
927:ValparaĂso Region
792:Miyagi Prefecture
415:inverse power law
359:
358:
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1377:
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1360:. Archived from
1335:
1326:
1320:
1319:
1317:
1315:
1290:
1284:
1283:
1281:
1279:
1273:
1267:. Archived from
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1227:
1226:
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1222:
1199:
1190:
1189:
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1185:
1156:
1147:
1146:
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1061:Kermadec Islands
739:
701:August 15, 2007
537:
478:
477:
452:transform faults
351:
344:
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122:Earthquake swarm
42:
19:
18:
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1576:
1572:
1571:
1567:
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1526:
1516:
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1468:
1464:
1454:
1452:
1451:on 16 June 2010
1441:
1437:
1384:
1380:
1370:
1368:
1364:
1333:
1327:
1323:
1313:
1311:
1309:
1291:
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1274:on 23 July 2011
1271:
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1218:
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1183:
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1179:
1157:
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1120:
1116:
1111:
1078:
1056:
1031:
1018:Central Croatia
1013:
988:
966:
941:
932:April 24, 2017
922:
897:
888:April 16, 2016
878:
853:
839:Tarapacá Region
834:
809:
800:March 11, 2011
787:
758:
749:April 21, 2007
738:
710:
688:
663:
641:
611:
594:Arauco Province
589:
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163:
162:Characteristics
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52:
17:
12:
11:
5:
1683:
1673:
1672:
1667:
1651:
1650:
1628:
1614:
1611:on 2011-03-12.
1596:
1582:
1565:
1544:(2): 246–255.
1524:
1462:
1435:
1378:
1367:on 3 July 2011
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1069:March 5, 2021
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550:April 4, 1904
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481:Foreshock Date
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323:Related topics
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140:Fault movement
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982:10.7 km
981:
979:July 5, 2019
978:
976:
975:United States
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935:24.8 km
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847:20.1 km
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188:Seismic waves
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1641:. Retrieved
1631:
1617:
1609:the original
1599:
1585:
1568:
1541:
1537:
1527:
1515:. Retrieved
1479:
1475:
1465:
1453:. Retrieved
1449:the original
1438:
1395:
1391:
1381:
1369:. Retrieved
1362:the original
1344:(1): 88–98.
1341:
1337:
1324:
1312:. Retrieved
1298:
1288:
1276:. Retrieved
1269:the original
1248:
1244:
1231:
1219:. Retrieved
1204:
1182:. Retrieved
1164:
1139:. Retrieved
1124:
1117:
1100:
1043:Strike-slip
1000:Strike-slip
909:Strike-slip
744:Aysén Region
502:(Mainshock)
488:(Foreshock)
440:
428:
411:
404:
392:
378:
374:
362:
360:
267:Other topics
72:Blind thrust
61:
1517:29 November
1455:29 November
1371:29 November
1314:29 November
1278:29 November
1221:29 November
1184:29 November
1141:29 November
1065:New Zealand
1025:10 km
891:11 km
803:30 km
771:Strike-slip
704:35 km
657:30 km
605:35 km
553:15 km
255:Forecasting
216:Seismometer
210:Measurement
183:Shadow zone
32:Earthquakes
1665:Seismology
1659:Categories
1109:References
971:California
752:6 km
693:Ica Region
431:nucleation
389:Occurrence
383:aftershock
367:earthquake
298:Seismology
239:Prediction
178:Hypocenter
112:Supershear
92:Megathrust
87:Intraplate
82:Interplate
67:Aftershock
650:Indonesia
520:Comments
505:Intensity
500:Magnitude
491:Location
486:Magnitude
425:Mechanics
379:mainshock
375:foreshock
371:mainshock
363:foreshock
168:Epicenter
145:Volcanism
107:Submarine
62:Foreshock
57:Mainshock
1504:15791246
1430:24526224
1398:: 4099.
1079:
1072:55.6 km
1057:
1032:
1014:
989:
967:
942:
929:, Chile
923:
898:
885:, Japan
879:
854:
841:, Chile
835:
810:
788:
759:
746:, Chile
711:
689:
664:
642:
612:
590:
560:
546:Bulgaria
483:(Delay)
318:Category
293:Seismite
24:a series
22:Part of
1643:July 9,
1546:Bibcode
1512:4337369
1484:Bibcode
1421:3924212
1400:Bibcode
1346:Bibcode
1253:Bibcode
1090:Thrust
953:Thrust
865:Thrust
821:Thrust
722:Thrust
675:Thrust
646:Sumatra
117:Tsunami
77:Doublet
1510:
1502:
1476:Nature
1428:
1418:
1305:
1212:
1175:
1132:
624:Thrust
572:Normal
497:Depth
365:is an
198:S wave
193:P wave
134:Causes
1577:(PDF)
1508:S2CID
1365:(PDF)
1334:(PDF)
1272:(PDF)
1241:(PDF)
1082:VIII
1075:8.1 M
1053:7.4 M
1028:6.4 M
1010:5.2 M
985:7.1 M
963:6.4 M
938:6.9 M
919:4.8 M
894:7.0 M
875:6.2 M
857:VIII
850:8.2 M
831:6.7 M
806:9.0 M
796:Japan
784:7.3 M
755:6.2 M
714:VIII
707:8.0 M
685:6.4 M
660:9.2 M
608:9.5 M
598:Chile
563:X-XI
556:7.0 M
517:Type
514:Name
494:Date
50:Types
1645:2019
1519:2010
1500:PMID
1457:2010
1426:PMID
1373:2010
1316:2010
1303:ISBN
1280:2010
1223:2010
1210:ISBN
1186:2010
1173:ISBN
1143:2010
1130:ISBN
1101:Note
945:VII
762:VII
732:5.2
697:Peru
615:XII
102:Slow
1554:doi
1542:148
1492:doi
1480:434
1416:PMC
1408:doi
1354:doi
1261:doi
1169:418
1035:IX
992:IX
901:IX
813:IX
667:IX
636:7.3
584:7.9
529:6.3
509:MMI
381:or
1661::
1552:.
1540:.
1536:.
1506:.
1498:.
1490:.
1478:.
1474:.
1424:.
1414:.
1406:.
1394:.
1390:.
1352:.
1342:94
1340:.
1336:.
1259:.
1249:97
1247:.
1243:.
1194:^
1171:.
1163:.
1151:^
1063:,
973:,
794:,
695:,
648:,
596:,
544:,
511:)
409:.
377:,
361:A
26:on
1647:.
1562:.
1556::
1548::
1521:.
1494::
1486::
1459:.
1432:.
1410::
1402::
1396:4
1375:.
1356::
1348::
1318:.
1282:.
1263::
1255::
1225:.
1188:.
1145:.
1077:w
1055:w
1030:w
1012:w
987:w
965:w
940:w
921:w
896:w
877:w
852:w
833:w
808:w
786:w
757:w
737:L
735:M
709:w
687:w
662:w
640:w
638:M
610:w
588:w
586:M
558:w
535:w
533:M
507:(
474:.
471:W
469:M
350:e
343:t
336:v
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