Now, I will tell u about something is volcano mountain. on October 26, 2010 we knew that the eruption of Mount Merapi have caused many casualties who died. beside it, many people who lost their belongings and even relatives. Because of the high activity of Mount Merapi, the area around Merapi, which must be sterilized within 20 km. Volcanic ash released by the Mount Merapi has even reached the area of Bogor. Now the activity of Merapi has begun to decline, but Mount Semeru started showing increased activity.and now I will explain about why volcanoes erupt?
|Eruption of Mount Merapi|
Volcano mountain is in whole world. But, location of volcano mountain that famous is volcano mountain in Pasific Ring of Fire. Pasific Ring of Fire is line between two tectonic flat that rubbing. If volcano mountain explode erupt, magma that inside mountain will out as lava. Indonesia has many volcano mountains in region such as Sinabung mountain, Krakatau mountain, Merapi mountain, Semeru mountain, Salak mountain, etc.
Magma consists of gases and vapors. If the gas and steam trapped in the magma flows, the magma would erupt. And, it will destroy the bud eruption of a volcano. When the magma does not contain a lot of gas, lava sprayed out in a long stream.
There are two kind of eruption is explosive eruption and non explosive eruption. Cause of eruption will be explosive or non explosive is viscosity from magma and content of gas. Magma with big viscosity (andesitic magma and rhyolitic magma) and big gas will cause explosive eruption. Meanwhile basaltic magma will cause non explosive eruption. There are three characteristic of non explosive eruption.
First, if the low viscosity magma, the eruption may be preceded by a burst of fire due to a release of gas. Second, if a high viscosity with low gas content, eruption caused lava dome formed (lava dome) such as Semeru mountain. And the last, magma that comes out to the surface to form lava flows are relatively easy, because the viscosity is low.
And then explosive eruption has three characteristic too. First, magma flow difficult, so high gas pressure causes the magma had been broken and thrown into the air. In the air occurred freezing, so magma become cold as cooling, a pyroclastic material (material in the form of fragments of stone / gravel hot) and volcanic ash (tephra).Second, gas and volcanic ash can reach a height of tens of kilometers. Volcanic ash will fall back to earth, often in places far enough because of wind.And third, eruptions can also cause pyroclastic flow , if the bursts of gas and ashes fell to the slopes of the mountain of hot clouds. Eruptions like this are the most dangerous and deadly.
There are five type of eruptions are Hawaiian, Strambolian, Vulcanian, Pelean, Plinian, Phreatomagmatic and Phreatic. Type of Hawaiian occured in the mountains in Hawai, the United States and this type is a non expolosive eruptions. Type of Strmbolian is considered half explosive eruptions, blast of gas and ash reach a relatively low altitude. And type of Vulcanian is a highly explosive eruptions, marked an explosion occured repeatedly. Bursts of gas and ash can be very high and too often fell as a pyroclastic flow. Type of Pelean is lave dome formed in crater of mountain and then collapsed that produce pyroclastic flow of as rock and ash. And then type of Plinian is hurling rhyolitik or andesitic magma to height of over 40 km, causing a rain of ash / rock can reach very long distances. It also remains accompanied pyroclastic flow. Sign of type Phreatomagmatic is eruption of magma along in unison with ground water hurling hurling rocks, lava flows and tephra. This is occurred because of magma inside the mountain to meet with shallow ground water resource. And type of Phreatic same as Phreatomagmatic, but no magma that comes out.
Eventhough eruption from mountai can destroy anything, but I always feel happy if could see the beauty of the mountains among the rice fields. looks very cool and make the heart feel good.
*heheh lebay bgt ya kata2 yang terakhir