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Volcanoes Fast Facts

Here's some background information about volcanoes,...

Posted: Mar 30, 2018 6:55 AM
Updated: Mar 30, 2018 6:56 AM

Here's some background information about volcanoes, mountains that open downward to a reservoir of molten rock.

Facts: More than 80% of the Earth's surface, both above and below sea level, is of volcanic origin.

Lava is molten rock from a volcano that reaches the Earth's surface. Liquid rock below the Earth's surface is referred to as magma.

Volcanoes are generally classified into four main types:
-
Cinder cones: These are the simplest type of volcanoes. They are hills, often steep, formed by an accumulation of congealed lava around a vent. When a cinder cone erupts, the ground shakes as magma rises. Then, a powerful blast throws lava, ash, and gas into the air.
Examples: Paricutin in Mexico, Sunset Crater in Arizona.

- Composite volcanoes or stratovolcanoes: These are symmetrical, cone-shaped and have a conduit system through which magma flows to the surface. They can rise 8,000 feet above their surroundings.
Examples: Mount St. Helens, Mount Fuji, Mount Shasta, Mount Cotopaxi, Mount Hood and Mount Rainier.

- Lava domes: These domes are small masses of lava that accumulate around and over the volcano's vent. Lava domes commonly are found inside the craters or on the flanks of large composite volcanoes.
Example: Mont Pel-e.

- Shield volcanoes: These form when lava cools to form a gently sloping dome. The Hawaiian island chain was created by oceanic shield volcanoes.
Examples: Mauna Loa and Kilauea in Hawaii.

There are more than 500 volcanoes that have erupted at least once in the world and 50 of them are located in the United States.

More than 50% of the world's active volcanoes above sea level encircle the Pacific Ocean, forming the "Ring of Fire." The ring stretches from New Zealand to the coast of South America.

In 2010, a volcano eruption in Iceland disrupted air travel for days across Europe. The eruption expelled an ash cloud 30,000 feet into the air. The International Air Transport Authority estimated that the airline industry lost $1.7 billion in revenue due to the disruption.

Deadliest Volcanic Eruptions since 1500 AD.

Volcanic Explosivity Index (VEI): The Volcanic Explosivity Index, which measures the relative explosiveness of volcanic eruptions, was devised in 1982. On a scale of 0-to-8, each number represents a tenfold increase in explosive power.

The VEI uses several factors to determine a number, including volume of erupted material, height of eruption column and duration in hours.

Major eruptions: Selected VEI 4 and above (1902 - current): Sources: NOAA Significant Volcanic Eruption Database and Smithsonian volcano database

Note: Dates listed cover the day of peak explosive activity.

May 6, 1902 - Soufri-re St. Vincent on the island of Saint Vincent erupts, resulting in about 1,680 deaths. (VEI 4)

May 8, 1902 - Pel-e on Martinique erupts, killing about 28,000 people. (VEI 4)

October 24, 1902 - Santa Maria in Guatemala erupts, resulting in about 2,500 deaths. (VEI 6)

June 6, 1912 - Novarupta volcano erupts in Alaska, killing two people. It is the largest volcanic eruption of the 20th century. (VEI 6)

January 20, 1913 - Colima in Mexico erupts. The number of deaths is unknown. (VEI 5)

May 19, 1919 - Kelut in Indonesia erupts, resulting in 5,110 deaths. (VEI 4)

January 21, 1951 - Mount Lamington in Papua New Guinea erupts and kills nearly 3,000 people. (VEI 4)

March 17, 1963 - Agung in Indonesia erupts, killing more than 1,000 people. (VEI 5)

March 29 1982 - El Chich-n in Mexico erupts, resulting in 1,879 deaths. (VEI 5)

May 18, 1980 - Mount St. Helens in Washington erupts, killing 57 people. (VEI 5)

June 15, 1991 - Pinatubo in the Philippines erupts, killing about 350 people. (VEI 6)

Oregon Coronavirus Cases

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Cases: 387485

Reported Deaths: 5116
CountyCasesDeaths
Multnomah59768836
Washington41571393
Marion39592504
Clackamas32426376
Lane29856354
Jackson24672350
Deschutes23182185
Umatilla15087180
Linn14488178
Douglas13236286
Josephine10057240
Yamhill9665142
Klamath8979145
Polk813698
Benton605137
Malheur591586
Coos5573106
Columbia423855
Jefferson416865
Lincoln357252
Union336854
Crook330156
Wasco314846
Clatsop258335
Baker217531
Tillamook214345
Hood River211337
Morrow197025
Curry190136
Harney119332
Grant108314
Lake104016
Wallowa74713
Sherman1903
Gilliam1844
Wheeler1141
Unassigned00

California Coronavirus Cases

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Cases: 5060666

Reported Deaths: 74152
CountyCasesDeaths
Los Angeles152491227121
San Diego4047084319
Riverside3849455306
San Bernardino3718825944
Orange3329505675
Sacramento1674002423
Kern1565171781
Fresno1558992246
Santa Clara1511691922
Alameda1246581504
San Joaquin1070001833
Ventura1036461188
Contra Costa1032921045
Stanislaus912991413
Tulare856141082
San Francisco56614669
San Mateo56058629
Monterey52340625
Solano47422356
Santa Barbara47035548
Merced44807664
Sonoma42912412
Placer41881468
Imperial38128769
Kings35038358
San Luis Obispo31294358
Madera26005311
Shasta25917440
Butte25295309
Santa Cruz22028222
Yolo21451257
Marin18342248
El Dorado18166161
Sutter14494181
Napa13372104
Yuba1070088
Tehama10230129
Humboldt10043117
Nevada9914103
Mendocino848894
Lassen792355
San Benito775977
Tuolumne767790
Lake6990110
Amador573766
Siskiyou470954
Glenn455136
Calaveras435685
Del Norte371242
Colusa323519
Inyo254345
Plumas19127
Mono18294
Mariposa156718
Trinity98817
Modoc7475
Unassigned2430
Sierra2170
Alpine1060
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