Term
|
Definition
| Iceland was born from volcanic activities in the Mid-Atlantic Ridge system, which is exposed above sea level (located in Northern Atlantic). 1973 - eruptions of small island Heimaey (southern coast) first time humans "fought" back. Used bulldozers to build barriers of pyroclastic flow and sprayed lava flow with ocean water. |
|
|
Term
|
Definition
| Produced by subduction zones, mainly containing Stratovolcanoes and deadly Caldera Volcanoes |
|
|
Term
|
Definition
| Outburst floods from under the islands ice caps. On sept 30tha fissure began opening along the mid-Atlantic spreading center beneath the thick ice cap Vatnajokull, no deaths, but was the 2nd largest river for two days destroying Icelands longest bridge. |
|
|
Term
| Subduction Zone Volcanoes |
|
Definition
| Galeras Volcano-Columbia, Mount Unzen-Japan, Mount Pinatubo and Mayon-Philippines, Mount St. Helens-Washington, and Soufriere Hills-Monsterrat. REgions around subduction zones heavily populated, these volcanoes are most devestating to humans and can affect the climate worldwide. |
|
|
Term
|
Definition
| Subduction Zone-Cascadia (Juan de Fuca plate subducting under North American plate). Created a volcanic arc, a chain of active and dormant volcanoes, of the cascade range. Stratovolcanoes dominate, some sheild, cinder cones and calderas. |
|
|
Term
|
Definition
| Not erupting, but shows many signs of potential eruption. |
|
|
Term
| Signs of Potential Eruptions |
|
Definition
1.) Steam vents and high heat flow within/under volcano.
2.) Volcanic gas concentrations increase as activity increases.
3.) Relativley recent volcanic deposits (age-dating pyroclastics/lava flows).
4.) Monitor seismic activity, quakes increase and get shallower prior to eruptions.
5.) Movement/shifting of earth around volcano as magma works its way up.
|
|
|
Term
|
Definition
| Cascade volcanoes don't erupt continuously but rather go through cycles of activity, dormancy varying from a few decades to a few centuries. |
|
|
Term
|
Definition
| Eruptive history of a volcano. Often hard to make an accurate prediction, uses intensive radiometric dating of the volcanic layers (flows/pyroclastics). |
|
|
Term
|
Definition
| Deadliest and most dangerous of volcanic hazards, associated with subduction zone volcanoes. |
|
|
Term
|
Definition
| Serious hazard, especially in the Cascades, volcanoes have large glaciers on their flanks, the rapid melting of ice triggers these dangerous lahars. |
|
|
Term
|
Definition
| "Nuee Ardents" or "Hot Ash FLows", deadliest of volcanic hazards. |
|
|
Term
| 4 different ways Pyroclastic Flows can form |
|
Definition
| 1.) Dome collapses 2.) Overspilling Crater Rim 3.) Direct Blast 4.) Eruption Column Collapse |
|
|
Term
|
Definition
| May 1991 growing lava dome, residents evacuated. Numerous collapses of 200-300 ft high masses. June 1991 larger than usual mass feel and rolled downslope at 60mph killing 44. |
|
|
Term
|
Definition
Kelut, Indonesia 1586 & 1919
Nevado del Ruiz, Columbia 1985
Mt. Rainer, Washington-On Alert |
|
|
Term
|
Definition
| Part of a failed rift system where Africa began to split apart but stopped. Very deadly gasses come up and concentrate on lake bottom. If lake overturned gases get released. |
|
|
Term
|
Definition
| Volcanic activity can kill thousands of crops and agricultural systems fail. |
|
|
