A Double Seismic Front and Earthquake Cycles Along the Coast of Oaxaca, Mexico

Núñez-Cornũ, F. J.

doi:10.1785/gssrl.67.6.33

Cited by 9 publications

(10 citation statements)

References 14 publications

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“…A seismogenic zoning (Núñez-Cornú 1996) including data between 1507 and 1982 highlighted that southern Oaxaca (roughly between 97°W and 95.5°W and 16°N and 16.3°N) shows seismic activity that is more regular in temporal behavior, in contrast with southwestern Oaxaca (between 99°W and 97°W and 15.7°N and 17.1°N) where only three large earthquakes took place during 1542-1787 (1655, Ms B 7.5; 1740, Ms B 8; and 1787 Ms C 8.4-the ''San Sixto'' earthquake). This was followed by a quiet period of 141 years, until the region generated seismicity again between 1928 and 2007 (earthquakes with magnitudes in the 7-7.4 range).…”

Section: Resultsmentioning

confidence: 99%

The great 1787 Mexican tsunami

2008

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Tsunamis have proven to represent a significant hazard around the globe and there is increased awareness about their occurrence. The Pacific coast in southern México is no exception, because there is firm evidence of the effects of past large tsunamis. Here we present results from computer-aided modeling of the March 28, 1787-''San Sixto'' earthquake and tsunami, and focus on the regions of Acapulco, Corralero, Jamiltepec, and Tehuantepec, located along the Guerrero-Oaxaca coast. The theoretical waveforms suggest wave heights in excess of 4 m and 18 m at specific locations in Acapulco and Corralero, respectively, and wave heights of at least 2 m at locations in Jamiltepec and Tehuantepec. From our modeling results and based on historical documents and the topography of the area, we conclude that these wave heights would have been sufficient to cause inundations that in the case of Acapulco were restricted to several meters inland, but in other areas like Corralero reached at least 6 km inland. Our results are consistent with published and unpublished damage reports that attest to the hazards associated with great earthquakes and tsunamis along the subduction zone in Mexico

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Section: Resultsmentioning

confidence: 99%

The great 1787 Mexican tsunami

2008

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“…2 and 3) and from the isoseismal maps of the 1928 sequence. After the 1787 event, this segment of the plate boundary apparently had a long period of quiescence for earthquakes M >7 that lasted 141 yr (Núñez-Cornú, 1996). The 1787 event appears to have broken a long segment of the plate boundary that is at least three times as Figure 1.…”

Section: Variable Rupture Length Along the Middle American Subductionmentioning

confidence: 96%

“…The coast of Oaxaca in southern Mexico is a good example of a segment of the Mexican subduction zone where earthquakes occur with relatively short recurrence times ranging in magnitudes from 7.3 to 7.7. It has been suggested that the large earthquakes that took place along the coast of Oaxaca in 1965Oaxaca in , 1968Oaxaca in , 1978Oaxaca in , and 1996 are the repeat of events of similar size earthquakes that occurred in the same region in 1928, yielding a repeat time of approximately 40 yr (Singh et al, 1981;Núñez-Cornú and Ponce, 1989;Núñez-Cornú, 1996).…”

Section: Introductionmentioning

confidence: 99%

Evidence for Great Tsunamigenic Earthquakes (M 8.6) along the Mexican Subduction Zone

Suárez¹,

Albini²

2009

Bulletin of the Seismological Society of America

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A very large earthquake took place on 28 March 1787 along the Mexican subduction zone. A unique characteristic of the 1787 event is the large tsunami reported at various coastal locations in southern Mexico. The segment of the coast affected by the strong tsunami coincides with locations where high felt intensities (modified Mercalli intensity [MMI] > VIII) were reported. Assuming, as is generally the case for large and great earthquakes in Mexico, that the fault rupture of the 1787 earthquake encompasses the areas where intensities greater than VIII were reported and where a strong tsunami invaded land, the estimated length of the rupture is approximately 450 km long. This fault length would correspond to an earthquake of approximately M w 8.6. In the instrumental record there is no evidence of earthquakes of this magnitude in the Middle American subduction zone. This evidence indicates that the rupture area of the 1787 earthquake was at least three times longer that those normally observed for earthquakes that take place in the Mexican subduction zone. The 1787 earthquake appears to have ruptured a long fault segment that more recently broke in earthquakes of more moderate magnitude (M w 7-8) and relatively short recurrence times of about 30 to 40 yr. Examples of this mode of variable rupture length where great but infrequent earthquakes rupture the fault areas of relatively smaller and more frequent earthquakes have been observed in the Sumatra-Andaman and Colombia-Ecuador plate boundaries, among others.

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“…2a), if indeed a M 8.6 earthquake occurred, a catastrophic tsunami with modelled wave heights of up to 20 m 12 could overpass a series of 4 to 6 m-height beach ridges ( Fig. 2a,b) and flood 6 km inland 8,12,15 .…”

mentioning

confidence: 96%

“…Corralero sits on the Oaxaca coast, a segment of the Mexican subduction with frequent earthquakes (every ± 40 years.) and magnitudes ranging from 7.3 to 7.7 [13][14][15] (Fig. 1a,b).…”

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Sand deposits reveal great earthquakes and tsunamis at Mexican Pacific Coast

Ramírez‐Herrera

Corona

Cerny

et al. 2020

Sci Rep

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Globally, instrumentally based assessments of tsunamigenic potential of subduction zones have underestimated the magnitude and frequency of great events because of their short time record. Historical and sediment records of large earthquakes and tsunamis have expanded the temporal data and estimated size of these events. instrumental records suggests that the Mexican Subduction earthquakes produce relatively small tsunamis, however historical records and now geologic evidence suggest that great earthquakes and tsunamis have whipped the Pacific coast of Mexico in the past. the sediment marks of centuries old-tsunamis validate historical records and indicate that large tsunamigenic earthquakes have shaken the Guerrero-oaxaca region in southern Mexico and had an impact on a bigger stretch of the coast than previously suspected. We present the first geologic evidence of great tsunamis near the trench of a subduction zone previously underestimated as potential source for great earthquakes and tsunamis. Two sandy tsunami deposits extend over 1.5 km inland of the coast. The youngest tsunami deposit is associated with the 1787 great earthquake, M 8.6, producing a giant tsunami that poured over the coast flooding 500 km alongshore the Mexican Pacific coast and up to 6 km inland. The oldest event from a less historically documented event occurred in 1537. The 1787 earthquake, and tsunami and a probable predecessor in 1537, suggest a plausible recurrence interval of 250 years. We prove that the common believe that great tsunamis do not occur on the Mexican Pacific coast cannot be sustained. Worldwide, instrumentally based assessments of tsunamigenic potential of subduction zones have underestimated the magnitude and frequency of great events 1-3 , to some extent because great earthquakes and tsunamis are infrequent 1-5 and instrumental seismic data are relatively short. Historical and sediment records of large earthquakes and tsunamis have expanded the temporal data and estimated size of these events but mainly where direct observations of great tsunamis have been possible 1,3,4,6. This means that little is still known of great earthquakes and tsunami generation potential of other subduction zones 7-11. Additionally, at the centre of the problem is still the question as to whether subduction zones, despite their relatively short instrumentally seismic history, could generate great earthquakes and tsunamis. We reveal the first geologic evidence, and validate historical records, of great tsunamis and earthquakes near the trench of the Mexican subduction zone previously underestimated as potential source for great earthquakes and tsunamis. Here, we focus on the Corralero coastal plain, in southwestern Mexico, where a great earthquake, M 8.6, triggered a giant tsunami that poured over the coast of Oaxaca, Guerrero, and Chiapas, flooding 500 km along open

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A Double Seismic Front and Earthquake Cycles Along the Coast of Oaxaca, Mexico

Cited by 9 publications

References 14 publications

The great 1787 Mexican tsunami

The great 1787 Mexican tsunami

Evidence for Great Tsunamigenic Earthquakes (M 8.6) along the Mexican Subduction Zone

Sand deposits reveal great earthquakes and tsunamis at Mexican Pacific Coast

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