  | |
| UTC time | 1942-08-24 22:50:31 |
|---|---|
| ISC event | 900444 |
| USGS-ANSS | ComCat |
| Local date | August 24, 1942 |
| Local time | 17:50 |
| Magnitude | Mw 8.2 |
| Depth | 35 km (22 mi) [1] |
| Epicenter | 14°59′S74°55′W / 14.98°S 74.92°W [1] |
| Type | Megathrust |
| Areas affected | Peru |
| Max. intensity | MMI IX (Violent) |
| Casualties | 30 |
The 1942 Peru earthquake occurred on August 24 at 17:50 local time and was located near the border of the departments of Ica and Arequipa, Peru. It had a magnitude of Mw 8.2 or Ms 8.4. [2] [3] [4]
This is a megathrust earthquake which ruptured part of the boundary between the Nazca plate and the South American plate. [5] [6] In this area, the Nazca plate is subducting beneath the South America Plate with a convergence vector of about 7.6 cm/yr. Much of the rupture zone of the 1942 earthquake overlapped with that of the 1996 Nazca earthquake. The rupture zone of the 1942 earthquake was about 40 km longer than that of the 1996 earthquake. [7] The epicenter of the 1942 earthquake was very close to, but slightly southeast of, that of the 1996 earthquake. [8] The energy released by the 1942 earthquake was about 2.5×1017 Nm. [4]
The earthquake caused 30 deaths and 25 injuries. Building damage was noteworthy in the epicentral area. About 30% of the buildings in the city of Nazca were ruined. There were slides in the hills. The intensity reached IX (Violent). [2]
This earthquake triggered a tsunami. In Callao, the amplitude of the oscillations of the tsunami was 1.6 m. [9] In Lomas, the sea receded more than 200 m, and then it flooded the settlement with injuries reported. [10]
Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.
The 1957 Andreanof Islands earthquake occurred at 04:22 local time on March 9 with a moment magnitude estimated at 8.6 and a maximum Modified Mercalli intensity of VIII (Severe). It occurred south of the Andreanof Islands group, which is part of the Aleutian Islands arc. The event occurred along the Aleutian Trench, the convergent plate boundary that separates the Pacific plate and the North American plates near Alaska. A basin-wide tsunami followed, with effects felt in Alaska and Hawaii, and strong waves recorded across the Pacific rim. Total losses were around $5 million.
The 1995 Antofagasta earthquake occurred on July 30 at 05:11 UTC with a moment magnitude of 8.0 and a maximum Mercalli intensity of VII. The Antofagasta Region in Chile was affected by a moderate tsunami, with three people killed, 58 or 59 injured, and around 600 homeless. Total damage from the earthquake and tsunami amounted to $1.791 million.
The Sunda megathrust is a fault that extends approximately 5,500 km (3300 mi) from Myanmar (Burma) in the north, running along the southwestern side of Sumatra, to the south of Java and Bali before terminating near Australia. It is a megathrust, located at a convergent plate boundary where it forms the interface between the overriding Eurasian Plate and the subducting Indo-Australian Plate. It is one of the most seismogenic structures on Earth, being responsible for many great and giant earthquakes, including the 2004 Indian Ocean earthquake and tsunami that killed over 227,000 people. The Sunda megathrust can be divided into the Andaman Megathrust, Sumatra(n) Megathrust and Java(n) Megathrust. The Bali-Sumbawa segment is much less active and therefore does not have the "megathrust" term associated with it.
The 1861 Sumatra earthquake occurred on 16 February and was the last in a sequences of earthquakes that ruptured adjacent parts of the Sumatran segment of the Sunda megathrust. It caused a devastating tsunami which led to several thousand fatalities. The earthquake was felt as far away as the Malay peninsula and the eastern part of Java. The rupture area for the 2005 Nias–Simeulue earthquake is similar to that estimated for the 1861 event.
The 1965 Rat Islands earthquake occurred at 05:01 UTC, on 4 February. It had a magnitude of 8.7 and triggered a tsunami of over 10 m on Shemya Island, but caused very little damage.
The 1996 Chimbote earthquake occurred on February 21 at 07:51 local time about 130 km off the coast of northern Peru, near the Peru–Chile Trench. The earthquake had a moment magnitude of 7.5 and occurred at 25.0 km (15.5 mi) depth.
The 1984 Northern Sumatra earthquake occurred with a moment magnitude of 7.2 on November 17 at 06:49 UTC. The epicentre was located off the coast of Sumatra, near the island of Nias, where building damage was reported. This earthquake could be strongly felt in parts of Northern Sumatra, including Padang and Medan. The focal mechanism corresponded to reverse faulting.
The 1935 Sumatra earthquake occurred at 09:35 local time on 28 December. It had a magnitude of Mw 7.7 and a maximum felt intensity of VII (Damaging) on the European macroseismic scale. It triggered a minor tsunami.
In seismology, a tsunami earthquake is an earthquake which triggers a tsunami of significantly greater magnitude, as measured by shorter-period seismic waves. The term was introduced by Japanese seismologist Hiroo Kanamori in 1972. Such events are a result of relatively slow rupture velocities. They are particularly dangerous as a large tsunami may arrive at a coastline with little or no warning.
The 1959 Kamchatka earthquake occurred on May 4 at 19:15 local time with a moment magnitude of 8.0–8.3, and a surface wave magnitude of 8.25. The epicenter was near the Kamchatka Peninsula, Russian SFSR, USSR. Building damage was reported in Petropavlovsk-Kamchatsky. The maximum intensity was VIII (Damaging) on the Medvedev–Sponheuer–Karnik scale. The intensity in Petropavlovsk-Kamchatsky was about VIII MSK.
The 1746 Lima–Callao earthquake occurred at 22:30 local time on 28 October with a moment magnitude of 8.6–8.8 and a maximum Mercalli intensity of XI (Extreme). The epicenter was located about 90 km (56 mi) north-northwest of the capital Lima, which was almost completely destroyed, and the subsequent tsunami devastated the port city of Callao. It was the deadliest earthquake in Peru's history prior to the 1970 earthquake.
The 1996 Nazca earthquake occurred on November 12 at 16:59 UTC. The earthquake was located offshore near Nazca, Peru. It has a magnitude of Mw 7.7. Fourteen people were reported dead. Four-thousand houses collapsed and 11,000 were partially damaged. Nazca and Acarí were the most affected cities. Liquefaction was observed in the bed of the Yauca River. The intensity was VIII (Severe) in Nazca. A tsunami was triggered by this earthquake. The recorded peak-to-trough heights of the tsunami were 25 cm in Callao, Peru and 35 cm in Arica, Chile.
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.
The 1979 Tumaco earthquake occurred at 02:59 local time on 12 December with a moment magnitude of 8.2 and a maximum Mercalli intensity of IX (Violent). The epicenter was just offshore from the border between Ecuador and Colombia, near the port city of Tumaco. It triggered a major tsunami, which was responsible for most of the estimated 300–600 deaths. The hardest hit area was Colombia's Nariño Department.
The November 1960 Peru earthquake occurred offshore northern Peru on November 20 at 17:02 local time. The magnitude of the earthquake was Ms 6.75 by using the conventional surface-wave magnitude measurement within a shorter duration of ~20 s. However, there is a large discrepancy between the magnitudes in Ms and Mw in this earthquake. The discrepancy was caused from the earthquake's long source duration of about 130 s, and by calculating the seismic moment, the magnitude would be Mw 7.6 or Mw 7.8, according to different sources. This earthquake belongs to a category of earthquakes with slow rupture velocities and potential of producing tsunamis larger than those expected from the moment magnitudes.
The 1942 Ecuador earthquake or the Guayaquil earthquake occurred on 13 May at 21:13 local time with a moment magnitude of Mw 7.9. The temblor struck the coastal (Esmeraldas) region of Manabí Province, Ecuador. It caused damage mainly to cities including Guayaquil, Portoviejo and Guaranda. More than 300 people were killed and the total cost of damage was about US$2.5 million. Ecuador's largest city Guayaquil was the most affected despite the significant distantce from the epicenter. Many reinforced concrete structures in a particular area in the city were completely destroyed, contributing to fatalities.
The 1604 Arica earthquake is an earthquake that occurred at 1:30 pm on November 24, 1604, offshore Arica, Chile. The estimated magnitude range is Ms8.0–8.5 and up to Mw8.7–9.0 and Mt8.8–9.0. It had a destructive tsunami that destroyed moust of Southern Peru, including Arica and Arequipa. 1,200–2,800 km (750–1,740 mi) of coastline was affected by the tsunami. The recorded effects of this earthquake are very similar to those for the 1868 Arica event, suggesting a similar magnitude and rupture area of the megathrust between the subducting Nazca plate and the overriding South American plate. Tsunami deposits have been identified on the Chatham Islands that are likely to have been caused by a trans-Pacific tsunami caused by the 1604 earthquake.
The earthquake cycle refers to the phenomenon that earthquakes repeatedly occur on the same fault as the result of continual stress accumulation and periodic stress release. Earthquake cycles can occur on a variety of faults including subduction zones and continental faults. Depending on the size of the earthquake, an earthquake cycle can last decades, centuries, or longer. The Parkfield portion of the San Andreas fault is a well-known example where similarly located M6.0 earthquakes have been instrumentally recorded every 30–40 years.
The 1979 Yapen earthquake occurred on September 12 at 05:17:51 UTC. It had an epicenter near the coast of Yapen Island in Irian Jaya, Indonesia. Measuring 7.5 on the moment magnitude scale and having a depth of 20 km (12 mi), it caused severe damage on the island. At least 115 were killed due to shaking and a moderate tsunami.