The Hawaiian Islands were formed by lava eruptions from volcanoes rather than internal solidification of magma, researchers of a new study found.
Contrary to previous beliefs that the Hawaiian Islands were formed because magma solidified internally before reaching the surface, researchers from the University of Hawaii and University of Rhode Island found that the islands formed by the eruption of lava on the surface.
The observations were made after studying and comparing a bunch of historical land-based gravity surveys with more recent surveys on the Big Island of Hawaii. Researchers claim that previous estimations of internally solidified magma versus extrusive lava flow (known as intrusive to extrusive ratio) were made on very short observations, hence the accuracy of the data is questionable.
"The discrepancy we see between our estimate and these past estimates emphasizes that the short term processes we currently see in Hawaii (which tend to be more intrusive) do not represent the predominant character of their volcanic activity," said Flinders.
"This could imply that over the long-term, Kilauea's ERZ will see less seismic activity and more eruptive activity that previously thought. The 3-decade-old eruption along Kilauea's ERZ could last for many, many more decades to come," said Dr. Garrett Ito, Professor of Geology and Geophysics at UHM and co-author.
Researchers found that this intrusive to extrusive ratio also affects the stability of a volcano's flank. Intrusive magma is denser and structurally stronger than lava flows. Since majority of a volcano is build from lava that erupts on the surface, researchers state that it could be the reason why volcanic collapses and eruptions take place.
"If the bulk of the islands are made from these weak extrusive flows then this would account for some of the collapses that have been documented, but this is mainly just speculation as of now,"said Flinders
