1991 Mount Pinatubo | |
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| Total costs | N/A |
| Deaths | 847 |
The 1991 eruption of Mount Pinatubo in the Philippines' Luzon Volcanic Arc was the second-largest volcanic eruption of the 20th century, behind only the 1912 eruption of Novarupta in Alaska. Eruptive activity began on April 2 as a series of phreatic explosions from a fissure that opened on the north side of Mount Pinatubo. Seismographs were set up and began monitoring the volcano for earthquakes. In late May, the number of seismic events under the volcano fluctuated from day-to-day. Beginning June 6, a swarm of progressively shallower earthquakes accompanied by inflationary tilt on the upper east flank of the mountain, culminated in the extrusion of a small lava dome.On June 12, the volcano’s first spectacular eruption sent an ash column 19 km (12 mi) into the atmosphere. Additional explosions occurred overnight and the morning of June 13. Seismic activity during this period became intense. When even more highly gas-charged magma reached Pinatubo's surface on June 15, the volcano exploded, sending an ash cloud 40 km (25 mi) into the atmosphere. Volcanic ash and pumice blanketed the countryside. Huge pyroclastic flows roared down the flanks of Pinatubo, filling once-deep valleys with fresh volcanic deposits as much as 200 m (660 ft) thick. The eruption removed so much magma and rock from beneath the volcano that the summit collapsed to form a small caldera 2.5 km (1.6 mi) across.Fine ash from the eruption fell as far away as the Indian Ocean and satellites tracked the ash cloud as it traveled several times around the globe. At least 16 commercial jets inadvertently flew through the drifting ash cloud, sustaining about $100 million in damage. With the ashfall came darkness and the sounds of lahars rumbling down the rivers. Several smaller lahars washed through the Clark Air Base, flowing across the base in enormously powerful sheets, slamming into buildings and scattering cars. Nearly every bridge within 30 km (19 mi) of Mount Pinatubo was destroyed. Several lowland towns were flooded or partially buried in mud. More than 840 people were killed from the collapse of roofs under wet heavy ash and several more were injured.Rain continued to create hazards over the next several years, as the volcanic deposits were remobilized into secondary mudflows. Damage to bridges, irrigation-canal systems, roads, cropland, and urban areas occurred in the wake of each significant rainfall. Many more people were affected for much longer by rain-induced lahars than by the eruption itself.
Source: Wikipedia 1988 Armenian earthquake | |
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| Total costs | N/A |
| Deaths | 25000 |
The 1988 Armenian earthquake, also known as the Spitak earthquake (Armenian: Սպիտակի երկրաշարժ, Spitaki yerkrasharj), occurred on December 7 at 11:41 local time with a surface wave magnitude of 6.8 and a maximum MSK intensity of X (Devastating). The shock occurred in the northern region of Armenia (then part of the Soviet Union) which is vulnerable to large and destructive earthquakes and is part of a larger active seismic belt that stretches from the Alps to the Himalayas. Activity in the area is associated with tectonic plate boundary interaction and the source of the event was slip on a thrust fault just to the north of Spitak. The complex incident ruptured multiple faults, with a strike-slip event occurring shortly after the initiation of the mainshock. Between 25,000 and 50,000 were killed and up to 130,000 were injured. Seismologists thoroughly studied the effects of the Spitak event, including the mainshock and aftershock fault rupture mechanisms, and were on site setting up temporary seismometers before the end of 1988. Earthquake engineering experts scrutinized building construction styles and found fault in the poorly constructed apartments and other buildings that were built during the Era of Stagnation under the rule of Leonid Brezhnev. The cities of Spitak, Leninakan (Gyumri) and Kirovakan (Vanadzor) were greatly affected with large losses of life and devastating effects to buildings and other structures. A number of the smaller outlying villages away from the larger population centers were also severely affected. Despite the tensions of the Cold War, Soviet leader Mikhail Gorbachev formally asked the United States for humanitarian help within a few days of the earthquake, the first such request since the late 1940s. One hundred and thirteen countries sent substantial amounts of humanitarian aid to the Soviet Union in the form of rescue equipment, search teams and medical supplies. Private donations and assistance from non-governmental organizations also had a large part of the international effort. While transporting some of these supplies to the region, a Soviet aircraft carrying 9 crew members and 69 military personnel, and a transport plane from Yugoslavia, were both destroyed in separate incidents. In support of the relief effort, recording artists united to produce several music-related contributions for the victims of the quake. A song was produced by a duo of French composers (including Charles Aznavour) and a studio album that featured songs donated by mainstream rock bands was released from the Rock Aid Armenia effort by the British music industry.
Source: Wikipedia
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