UTC time | 1931-01-15 01:50:47 |
---|---|
ISC event | 906564 |
USGS-ANSS | ComCat |
Local date | January 14, 1931 |
Local time | 18:50:47 MST |
Magnitude | 8.0 Ms [1] |
Depth | 40 km (25 mi) |
Epicenter | 16°02′13″N96°34′59″W / 16.037°N 96.583°W |
Type | Dip-slip |
Areas affected | Mexico |
Max. intensity | MMI X (Extreme) [2] |
Casualties | 114 [3] |
The 1931 Oaxaca earthquake affected portions of southern Mexico on January 14 at 18:50 MST. It registered a magnitude of 8.0 on the surface-wave magnitude scale and had a maximum perceived intensity of X (Extreme) on the Mercalli intensity scale. [2]
The state of Oaxaca lies above the convergent boundary where the Cocos plate is being subducted below the North American plate at a rate of 6.4 cm/yr. The dip of the subducting slab is about 15° as defined by focal mechanisms and earthquake hypocenters. Seismicity in this area is characterised by regular megathrust earthquakes along the plate interface. In addition, there have been a series of historical normal fault events within the subducting slab. The area affected by moderate seismic intensities is about four times greater for the normal fault events compared to those on the plate interface and the peak horizontal acceleration is also higher in most cases. [4]
The earthquake is characterized as a normal fault event, and was the strongest in that area since the 1911 Michoacán earthquake. It caused no surface ruptures and did not generate a tsunami. From limited seismographic data, it is inferred to have had a focal depth of about 40 km. Analysis indicates that the rupture occurred deep down-dip within the subducted lithospheric slab, possibly breaking through the entire thickness of the slab. [1]
Early reporting from the Los Angeles Times described the city of Oaxaca as being in ruins. [5] Seventy per cent of its buildings were either completely destroyed or badly damaged. [6] Messages were said to be fragmented coming over damaged communication systems as a result of telegraph lines having been knocked down. One message that did get through was from General Evaristo Perez, a military commander in the state of Oaxaca, to president Pascual Ortiz Rubio stating at least 25 persons were dead. [5] Veracruz and Tampico reported light damage and one death was reported in Mexico city. [5] The town of Miahuatlán de Porfirio Díaz, located between Oaxaca and the coast, was reported to be completely destroyed. [7]
Russian filmmaker Sergei Eisenstein, who was in Mexico working on a film, flew to Oaxaca shortly after the earthquake to film conditions in the affected area. [8] After having returned to Mexico City, Eisenstein reported on the deaths of 71 persons in Guelatova while attending a fiesta in a church there. [9] A total of 114 deaths were ultimately attributed to the earthquake. [3]
Many people abandoned the city of Oaxaca after the earthquake and low property prices meant that a small number of families were able to gain ownership of most of the city. [6] A magnitude 7.5 earthquake on September 30, 1999 had a hypocenter close to that of the 1931 earthquake. [10]
The January 2001 El Salvador earthquake struck El Salvador on January 13, 2001, at 17:33:34 UTC. The moment magnitude 7.7 earthquake struck with the epicenter 60 miles (100 km) SW of San Miguel, El Salvador at a depth of 60 km.
In the early morning hours of August 16, 1931, a powerful earthquake occurred in West Texas with a maximum Mercalli intensity of VIII (Severe). Estimates of its magnitude range between 5.8 and 6.4 mb, making it the most powerful earthquake ever recorded in Texas history. Its epicenter was near the town of Valentine, Texas; there, the earthquake caused damage to many homes and buildings. The earthquake may have been caused by movement along oblique-slip faulting in West Texas, the most seismically active region in the state. Shaking from the earthquake was perceptible within a 400 mi (640 km) radius of the epicenter, affecting four U.S. states and northern Mexico. Several foreshocks and aftershocks accompanied the primary temblor, with the aftershocks continuing until at least November 3, 1931. The main earthquake caused no fatalities, though several people sustained minor injuries; the damage in Valentine amounted to $50,000–$75,000.
The 1999 Oaxaca earthquake occurred on September 30 at 11:31 local time in Oaxaca, Mexico, 60 km NNW of Puerto Ángel. The epicenter was located near San Agustin Loxicha. It had a magnitude of Mw 7.4.
The 1932 Jalisco earthquakes began on June 3 at 10:36 UTC with a megathrust event that registered 8.1 on the moment magnitude scale. With a maximum perceived intensity of X (Extreme) on the Mercalli intensity scale, at least 400 deaths were caused in Mexico and neighboring Guatemala. It was the first of a series of seismic events that affected parts of western Mexico during the month of June 1932, all reaching magnitude 7 or greater.
The 2012 Guerrero–Oaxaca earthquake struck southern Mexico with a moment magnitude of 7.4 at 12:02 local time on Tuesday, 20 March. Its epicenter was near Ometepec, in the border between the states of Guerrero and Oaxaca. With a shallow focus of 20 km, the earthquake caused strong shaking over a large area along the Oaxaca–Guerrero border and the adjacent Pacific coastline. Significant tremors were felt in areas up to several hundred kilometers away, including Mexico City and also in Guatemala. Two people were killed and over 30,000 houses were damaged or destroyed.
The 1906 Aleutian Islands earthquake occurred at 00:11 UTC on August 17. It had an estimated seismic moment of 3.8 x 1028 dyn cm−1, equivalent to a magnitude of 8.35 on the moment magnitude scale. This earthquake was followed thirty minutes later by the 1906 Valparaíso earthquake in Chile, but the two events are not thought to be linked. Due to the remote location, there are no reports of damage associated with this earthquake. A transpacific tsunami reported from Japan and Hawaii was triggered by the Chilean event, rather than the Aleutian Islands earthquake.
The 1981 Playa Azul earthquake occurred on October 24, 1981, at 21:22 local time. It was located near Playa Azul, Michoacán, Mexico. The magnitude of the earthquake was Mw 7.2, or Ms 7.3. Three deaths were reported, two from Michoacán and one from Mexico City. Some buildings were damaged in both Michoacán and Mexico City. A small tsunami was registered in Acapulco with a maximum height of 9 cm.
A deep-focus earthquake in seismology is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere. They occur along a dipping tabular zone beneath the subduction zone known as the Wadati–Benioff zone.
The 1787 New Spain earthquake, also known as the San Sixto earthquake, occurred on 28 March at 11:30 local time. It caused a large tsunami that affected the coast of the Puebla Intendancy and the Oaxaca Intendancy in Southwestern New Spain. With an estimated magnitude of 8.6 on the moment magnitude scale, it was more powerful than any instrumentally recorded Mexican earthquake.
The 1975 Bagan earthquake occurred on July 8 at 6:34 pm local time in Bagan, Myanmar. Many important stupas and temples were destroyed. The strongest intensity was felt in the towns of Nyaung-U, Pakokku, and Yesagyo, and in the Myaing townships on the confluence of the Ayeyawady River. Damage was also reported in Chauk and Natmauk townships. It had a magnitude of Mw 7.0.
The 2017 Chiapas earthquake struck at 23:49 CDT on 7 September in the Gulf of Tehuantepec off the southern coast of Mexico near the state of Chiapas, approximately 87 kilometres (54 mi) southwest of Pijijiapan, with a Mercalli intensity of IX (Violent). The moment magnitude was estimated to be Mw8.2.
The 2018 Oaxaca earthquake occurred on February 16, 2018 at 17:39 local time in the Sierra Madre del Sur mountains in Oaxaca state in Southern Mexico. It had a magnitude of 7.2 on the moment magnitude scale and a maximum felt intensity of VII on the Mercalli intensity scale. The hypocenter was located at a depth of 24.6 km and approximately 37 km northeast of Pinotepa de Don Luis. There were only two reports of injuries from the earthquake, but later a military helicopter surveying the damage crashed and killed 14 people. There were also 15 people injured.
The 1982 Ometepec earthquake that struck Mexico's southwestern coast near Ometepec (Guerrero) on 7 June was a doublet earthquake that ruptured in two steps. The first happened at 06:52 UTC, the second five hours later at 10:59 UTC. Estimated magnitudes are 6.9 and 7.0 on the Ms scale, and 5.8 and 6.0 on the mb scale. The maximum Mercalli intensities were VII and VIII, respectively.
On November 29, 1978 a moment magnitude 7.7–7.8 earthquake struck off the coast of the southern Mexican state Oaxaca. The thrust-faulting event caused severe damage in Oaxaca and Mexico City.
On January 30, 1973, at 15:01 (UTC–6), a magnitude 7.6 earthquake struck 35.3 km (21.9 mi) beneath the Sierra Madre del Sur range in the Mexican states of Colima, Jalisco and Michoacán. On the Mercalli intensity scale, the earthquake reached a maximum intensity of X (Extreme), causing serious damage in the region. At least 56 people were killed and about 390 were injured. The event is commonly referred to as the Colima earthquake.
The 1920 Xalapa earthquake affected the Trans-Mexican Volcanic Belt in the states of Puebla and Veracruz, Mexico on 3 January at 22:25 CST. It was the second deadliest to affect Mexico, behind the 1985 Mexico City earthquake. The earthquake measured 6.3–6.4 on the moment magnitude scale. An area around the epicenter, located between Chilchotla and Patlanalán, was assigned the maximum intensity of XI–XII (Extreme) on the Modified Mercalli intensity scale. Aftershocks following the earthquake were studied to determine that it originated at a depth of 15 km (9.3 mi) of less. The focal mechanism indicated that the shock was the result of faulting along an east–west striking normal fault beneath the volcanic belt.
The 1979 Petatlán earthquake, also known as the IBERO earthquake occurred on March 14 at 05:07 local time in the Mexican state of Guerrero. The earthquake had a surface wave magnitude of Ms 7.6 or moment magnitude of Mw 7.4 and maximum Modified Mercalli intensity of VIII (Severe). The epicenter, onshore, was located 12 km south southeast of Vallecitos de Zaragoza.
The 1950 Calama earthquake occurred near the Argentina–Chile border with an epicenter near Calama, Chile in the Atacama Desert on December 9. The event had a hypocenter depth of 113.9 km, beneath the Caichinque volcanic complex. It measured magnitude Mw 8.2 on the moment magnitude scale, making it the largest intermediate depth earthquake ever recorded on Chilean soil. One person was killed and an unspecified number of people were injured in Calama.
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