The USGS Hawaiian Volcano Observatory developed a new study on the activity of Kilauea Volcano, this time focusing on the gravity anomalies found in the vicinity.
The force of gravity depends on the mass of the object and the distance to the object. Thus, it may not be constant all over our planet.
A solidified magma chamber is very dense, which triggers a larger mass within the same volume.
Regarding the distance, a person standing on a top of a mountain experiences a lower gravity force, and thus it also weights less.
Inside the surface of the Earth, the accumulation of magma can push the ground upward. In the same time, the higher density causes gravity to rise in the area over the magma chamber.
The scientists measured gravity and surface deformation in order to separate the two effects. Moreover, they used gravity anomalies to discover how magma is moving under the ground.
The observatory team studied gravity changes starting with the 1970s, by taking measurements at specific points over the surface. A first conclusion was that the magma was not stored in one single chamber, but in interconnected caverns with different sizes.
For example, during the 2011 Kilauea Volcano eruption the scientists observed a major decrease in gravity in Halemaumau. The researchers concluded that the zone was most probably the source of the lava that was pushed on the surface and produced the eruption.
„Kīlauea is a wonderful “natural laboratory” in which we can develop advanced methods of volcano monitoring and research, like continuous gravity,” said the Observatory’s team in a recent activity report.
The scientists tried to obtain more information on the density of the underground magma. They measured the density of the basaltic rocks, which are 2.5 denser than water. Following their discoveries, the researchers approximated that lava could be slightly less thick as the magma also contains gasses.
The latest measurements showed that the lava density remained low, similar to the one of water. Moreover, the magma closer to the surface may also contain more gasses.
In the last years, some abrupt changes in gravity made scientists conclude that new batches of lava had been pushed near the summit.
The Kilauea Observatory is crucial in researching new methods of volcano monitoring. The results of its activity could be used by other scientists to predict the movements of active volcanoes situated close to communities.
The Kilauea Volcano continues to erupt near its summit and in the eastern zone. Last week, the lava flow reached a length of 4.5 miles. The eruption presents no danger to the local communities.
As for Mauna Loa, the volcano is quiet for now, and no earthquakes were reported during the last week.
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