UTC time | Doublet earthquake: |
---|---|
A: 1997-02-27 21:08 | |
B: 1997-02-27 21:30 | |
ISC event | |
A: 1013076 | |
B: 1013084 | |
USGS-ANSS | |
A: ComCat | |
B: ComCat | |
Local date | February 28, 1997 |
Local time | |
A: 2:08 | |
B: 2:30 | |
Magnitude | |
A: Mw 7.0 [1] | |
B: Ms 6.4 [2] | |
Depth | 33 km (21 mi) |
Epicenter | 29°58′34″N68°12′29″E / 29.976°N 68.208°E |
Max. intensity | MMI VIII (Severe) |
Casualties | 100 |
The 1997 Harnai earthquake occurred on February 27 at 21:08 UTC near Harnai, Pakistan, and felt throughout much of central Balochistan, [3] with a magnitude estimated at 7.0 on the Mw scale. [4] A 2016 study [5] determined that this was a doublet earthquake, the Mw 6.8 shock that hit 19 seconds later being a continuation of the initial main shock. The largest aftershock was an Ms 6.4 shock that hit 22 minutes after the main shock. The earthquake was caused by the collision between the Indian plate and the Eurasian plate. [6]
The mountainous villages near Quetta, the capital of Balochistan province, suffered most of the damage. Small villages in Sibi District, with mostly adobe dwellings, were completely destroyed, and the town of Harnai alone had 75 fatalities. The total number of deaths due to the earthquakes was over 100. [7]
An earthquake occurred on November 27, 2005, at 13:52 IRST on the sparsely populated Qeshm Island off Southern Iran, killing 13 people and devastating 13 villages. It was Iran's second major earthquake of 2005, following the one at Zarand in February. The epicenter was about 1,500 kilometers (930 mi) south of Tehran, close to Iran's southern borders. Initial measurements showed that the earthquake registered about 6.0 on the moment magnitude scale, although that was reduced to 5.8 after further analysis. More than 400 minor aftershocks followed the main quake, 36 of which were greater than magnitude 2.5. The earthquake occurred in a remote area during the middle of the day, limiting the number of fatalities. Iranian relief efforts were effective and largely adequate, leading the country to decline offers of support from other nations and UNICEF.
The 2005 Hindu Kush earthquake hit northeastern Afghanistan with a magnitude of 6.5 on December 12 at 21:47 (UTC). According to the United States Geological Survey, the maximum Mercalli intensity was V (Moderate) at Chitral. Five people were killed in the Hindu Kush region and landslides blocked several roads near Bagh, Kashmir. The earthquake occurred some 65 miles away from Faizabad, a city in the Hindu Kush mountains, but it could be felt in many neighboring areas. It could even be felt about 200 miles away in Islamabad, Pakistan. The quake was strong enough to trigger panic among survivors of October's devastating earthquake, who came out from their makeshift shelters in freezing temperatures. Although magnitude–6 earthquakes typically cause severe damage, this quake caused relatively little due to the fact that it occurred deep underground.
The 1976 Songpan–Pingwu earthquake that struck Songpan and Pingwu counties in Sichuan, China consisted of three mainshocks on the 16th, 21st, and 23rd (UTC) of August. A 1984 report gave the magnitudes as 7.2, 6.7, and 7.2, respectively. The magnitudes were subsequently recalculated as 6.7, 6.3, and 6.4 on the Mw scale, and 7.0, 6.6, and 6.7 on the Ms scale. These were preceded by an earthquake swarm lasting three years. During the period from August 16 to August 31 there were over 400 aftershocks of magnitude 3.0 or greater.
The 2008 Iceland earthquake was a doublet earthquake that struck on 29 May at 15:46 UTC in southwestern Iceland. The recorded magnitudes of the two main quakes were 5.9 Mw and 5.8 Mw , respectively, giving a composite magnitude of 6.1 Mw . There were no human fatalities, but injuries were reported and a number of sheep were killed. The epicenter of the earthquake was between the towns of Hveragerði and Selfoss, about 45 kilometers (28 mi) east-southeast of the capital, Reykjavík. It was the strongest earthquake to hit Iceland since the summer of 2000.
The 2009 West Papua earthquakes occurred on January 4 local time in Indonesia's Tambrauw Regency in Southwest Papua. The very large earthquake doublet comprised a Mw 7.6 initial shock that had a maximum Mercalli intensity of VI (Strong) and a second event measuring Mw 7.4 and a maximum Mercalli intensity of VII. The events took place less than three hours apart to the east-northeast of Sorong on the Bird's Head Peninsula and left at least four people dead and dozens injured.
The 1995 Neftegorsk earthquake occurred on 28 May at 1:04 local time on northern Sakhalin Island in the Russian Far East. It was the most destructive earthquake known within the current state of Russia, with a magnitude of Ms7.1 and maximum Mercalli intensity of IX (Violent) that devastated the oil town of Neftegorsk, where 1,989 of its 3,977 citizens were killed, and another 750 injured.
In seismology, doublet earthquakes – and more generally, multiplet earthquakes – were originally identified as multiple earthquakes with nearly identical waveforms originating from the same location. They are now characterized as distinct earthquake sequences having two main shocks of similar magnitude, sometimes occurring within tens of seconds, but sometimes separated by years. The similarity of magnitude – often within 0.4 magnitude – distinguishes multiplet events from aftershocks, which start at about 1.2 magnitude less than the parent shock and decrease in magnitude and frequency according to known laws.
The 2010 Oaxaca earthquake struck Oaxaca, Mexico on June 30, 2010, with an Mw magnitude of 6.3. Many people in different cities left their beds and ran into the street, as the quake struck at 2:22 am.
The 1967 Mudurnu earthquake or more correctly, the 1967 Mudurnu Valley earthquake occurred at about 18:57 local time on 22 July near Mudurnu, Bolu Province, north-western Turkey. The magnitude 7.4 Mw earthquake was one of a series of major and intermediate quakes that have occurred in modern times along the North Anatolian Fault since 1939.
The 2010 Mindanao earthquakes occurred in the southern Philippines in the Moro Gulf. This was a complex sequence of events including three main events of Mw magnitude 7.3 or greater on the 23rd of July, and two significant aftershocks of magnitude 6.6 on the 24th and 29th. All of these were deep focus earthquakes, at depths from 565 km (351 mi) to 634 km (394 mi). This resulted in minimal, but very widespread shaking at the surface, with a maximum intensity of IV on the PEIS scale; consequently there were no reports of casualties or damage.
The 2011 Dalbandin earthquake occurred on 19 January at 01:23 a.m. local time with a moment magnitude of Mw 7.2 and a maximum Mercalli intensity of VII. The shock occurred in a sparsely populated area of Balochistan, caused moderate damage, three deaths, and some injuries.
The 2011 Lorca earthquake was a moderate 5.1 Mw earthquake that occurred 6:47 p.m. CEST on 11 May 2011, near the town of Lorca, causing significant localized damage in the Region of Murcia, Spain, and panic among locals, and displacing many from their homes. The quake was preceded by a magnitude 4.4 foreshock at 17:05, that inflicted substantial damage to many older structures in the area, including the historical Espolón Tower of Lorca Castle, the Hermitage of San Clemente and the Convent of Virgen de Las Huertas. Three people were killed by a falling cornice. A total of nine deaths have been confirmed, while dozens are reported injured. The earthquake was the worst to hit the region since a 5.0 Mw tremor struck west of Albolote, Granada in 1956.
The 2012 East Azerbaijan earthquakes – also known as the Ahar earthquakes – occurred on 11 August 2012, at 16:53 Iran Standard Time, near the cities of Ahar and Varzaqan in Iran's East Azerbaijan Province, approximately 60 kilometers from Tabriz. They comprised a doublet separated by eleven minutes, with magnitudes of 6.4 and 6.2 Mww. At least 306 people died and more than 3,000 others were injured, primarily in the rural and mountainous areas to the northeast of Tabriz. The shocks were felt in Armenia and the Republic of Azerbaijan, though no major damage was reported.
The 1990 Vrancea earthquakes were three earthquakes on 30 and 31 May 1990 with magnitudes of 7.0 Mw and 6.2 Mw that struck the Romanian county of Vrancea, on two consecutive days. Severe damage in the Bucharest-Brăila-Brașov area was reported and dozens of casualties in Romania and neighbouring Moldova, Ukraine and Bulgaria.
The 2013 Balochistan earthquakes were the deadliest to affect Pakistan since 2005. The mainshock, occurring on 24 September, had a moment magnitude of 7.8 and maximum Mercalli intensity of IX (Violent). It had an epicenter located in Awaran District, 113 km (70 mi) northwest of Bela. The mainshock killed over 820 people, injured hundreds of others, and left 100,000 people homeless. The Awaran District was among the worst affected with 80 percent of its housing stock damaged or destroyed. On 28 September, the region was affected by a Mw 6.8 aftershock, killing an additional 15 people. Rescue and recovery efforts were severely hampered by insurgents who attacked military troops sent to distribute aid. These attacks also prompted the Pakistan government to close its doors to international aid.
The 1976 Longling earthquake in Yunnan Province, People's Republic of China, was a doublet earthquake, with two main shocks striking just east of Longling at 12:23:20 and 14:00:22 UTC. The magnitudes were estimated at 6.7 and 6.6, respectively, on the Mw(GCMT) scale, and 6.9 and 7.0 on the Ms scale; Chinese sources put these at 7.4 and 7.3 on the Ms7 scale. The region is noted for the quantity and intensity of its earthquakes, and the complexity of its tectonics, which are closely related to the collision between the Indian and Eurasian tectonic plates.
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.
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