1999 Oaxaca earthquake

Earthquake

The Cocos plate subducts under Oaxaca at approximately 6.4 cm/yr. This was an intraplate earthquake in the Cocos plate, with a normal-faulting mechanism. A similar normal-faulting earthquake was observed in June of the same year. The fault plane was 90 km long and 45 km wide. The maximum slip was about 2.5 m, which was located about 20 and 40 km WNW of the hypocenter. The maximum intensity reached MM VIII in southwestern Oaxaca, and could be felt strongly in Mexico City. A total of 21 aftershocks of 4.0-4.7 were reported.

Impact

The torrential rains and flooding preceding and following the temblor intensified the damage of this earthquake. Thirty-five people were reported dead, although another source states forty-six deaths with 215 injuries. Nearly 1.5 billion pesos of damage was accounted for, and over 45,000 homes were destroyed or damaged. The archeological site of the ancient Zapotec city of Monte Alban also suffered damage in this earthquake.

References

References

1. "USGS Earthquake Hazards Program: Earthquake Report: OAXACA, MEXICO". United States Geological Survey.
2. (September 30, 1999). "The Mexico Earthquake, September 30, 1999". Mceer.buffalo.edu.
3. "M 7.5 - 15 km W of San Baltazar Loxicha, Mexico".
4. (2000). "The Oaxaca Earthquake of 30 September 1999 (Mw = 7.5): A Normal-faulting Event in the Subducted Cocos Plate". Seismological Research Letters.
5. "Archived copy".
6. (2005). "Stochastic Modeling of the 30 September 1999 Mw 7.5 Earthquake, Oaxaca, Mexico". Bulletin of the Seismological Society of America.
7. "CNN Earthquake jolts Mexico City – September 30, 1999". CNN.
8. "Archived copy".
9. (2025-04-10). "Se cumplen 24 años del terremoto que azotó Oaxaca en 1999 {{!}} NVI Noticias".
10. (October 3, 1999). "Quake Damaged Pre-hispanic Ruins, Archeological Sites". Chicago Tribune.