And while it may be hard for outsiders to understand, that reverence can play an important role in how residents feel about eruptions. According to Holmberg, the owner accepted the loss quite readily. Saying that, similar attitudes can be found across the Pacific.
Of course, there are many people who live on volcanoes less out of reverence for them and more out of necessity. Others have been forced to live near volcanoes with tragic consequences. In , many slaves working on plantations near the volcano died during a powerful eruption. After another devastating from , subsistence farmers—often the freed descendants of former slaves—were given little to no financial help to rebuild their lives, unlike their white counterparts.
Even today, those living nearest the volcano in the north are still the poorest and most vulnerable on the island. The epicenter of the quakes clustered in a central region of the volcano's lava dome complex, about 20 meters south of the north crater wall. The source was a few hundred meters under the top of the dome. These seismic signals, we hypothesize, could have been caused by gas pressure associated with the escape of gases from rising magma.
The gas might accumulate slowly within a shallow pocket in the conduit, building up pressure against the rock wall. When the pressure is greater than the rock's strength, the gas pocket can push the rock surrounding it, causing what's known as radially outward tilt, or inflation. As the gas is released, the pocket shrinks and the rock returns to rest, causing radially inward tilt, or deflation.
Another potential cause of these seismic signals is called the "stick-slip rebound" model. This occurs when a brief, episodic, and unsteady upward movement of magma occurs in the volcano's conduit. Earthquakes could be produced when the mostly crystalline, highly viscous magma coming up the conduit rubs against the rocks in the conduit wall.
What we have detected as multiphase earthquakes could be the vibrations of the volcano wall caused by this magma movement. Both mechanisms indicate that we have detected shallow magma movement near the summit of the volcano. What does our research mean for the million people living around Merapi? First, as Voight says, "we have to separate our research objective from the practical objective. If we are successful, it may convert to practical consequences.
Our study of earthquakes at Merapi is part of an attempt to learn what happens beneath the volcano before it erupts. So far, we have shown that our temporary seismic network at the rim crater can detect better earthquake signals from within the volcano.
Particularly, we found that earthquakes having this very-long-period signature may be caused by shallow magma activity. If a lot of these earthquakes occur, we think it means that the volcano activity has become shallower and an eruption could occur in the near future. Seismic studies alone are not sufficient to provide early warning. But in combination with other methods, such as deformation and volcanic gas monitoring and geological study, they will yield a better understanding of Merapi's behavior and will help the volcanology team to better alert people living around the volcano.
His adviser is Barry Voight, Ph. Their work is funded by the National Science Foundation. Research Living With a Volcano. January 01, By Dannie Hidayat. Year Published: Volcanic hazards in the Pacific U. View Citation.
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Neal, Christina A. Year Published: Encounters of aircraft with volcanic ash clouds; A compilation of known incidents, Information about reported encounters of aircraft with volcanic ash clouds from through has been compiled to document the nature and scope of risks to aviation from volcanic activity. Guffanti, Marianne; Casadevall, Thomas J. Year Published: Instrumentation recommendations for volcano monitoring at U.
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