Hawaii is an island chain born by continual volcanic activity. Hawaii sits over a hot stop that steadily effuses lava. As the continental plates slowing migrate across the top of this hotspot, lava builds up forming sea mounds. When the lava builds up enough to emerge from the ocean, a new island is born.
Mt. Kīlauea on the Southeast part of the Big Island (Hawaii Island) has been steadily emitting lava from its crater and through lave tubes into the ocean since 1983. Continual lava emission has created a cone around Kilauea as well as a ridge and rift valley. The lava from Kilauea had been pouring through lava tubes that cut through Puna Ridge to the ocean.
However, just 2 weeks ago, an area south of the Kilauea caldera called the Hilina Slump began to slip. The usual lava tubes collaped causing lava to fill up in Lilauea forming a lava lake. The lava lake filled intil new lava tubes and fissures opened up allowing lava to flow away from the caldera. The lava lake drained as lava began to flow into the rift valley and into several poorly placed neighborhoods. New fissures will continue to open up until the lava from Kilauea finds an unimpeded path to the ocean.
Steam explosions are now occuring at the Kilauea caldera as the lava lake level has fallen below the ground water level. In this situation, rocks from the caldera sidewall fall into the volcano forming a plug. As groundwater flows into the caldera, it is turned into steam and pressure builds behind these rock plugs which are expected to create intermittent steam explosions releasing large ash clouds and potentially hurling larger rocks and boulders miles from the volcano.
The new fissures and steam explosions are only a concern for those people living in the rift valley in the new path of the lava and the area immediately around the caldera. Ash clouds can also be a clean-up problem. Sulfur dioxide gas can potentially collect in low-lying areas and displace oxygen which could cause asphyxiation of unsuspecting people or animsls.
However, it the slipping of the Hilina Slump into the ocean that is of greater concern for the west coast of the Americas. If the Hilina Slump were to give way suddenly and catastrophically slide off into the ocean, it would create a mega-tsunami that would destroy all the cities along the west coast of North and South America. The most powerful 10.0 earthquakes can only create tsunamis so large because ocean thrust faults can only move so much. However, much larger and destructive tsunamis can be created only when a large amount of rock or ice suddenly slides into the ocean.
A geothermal plant operates next to Kilauea. I hope as we see the Hilina Slump already slipping that the plant not only shuts down but also completely depressurizes all its wells. We don’t need pressurized wells potentially contributing to more slump slippage.