The Hawaiian Islands are a mountainous volcanic chain found in the Pacific Ocean that formed above a “hotspot”. Hawaii National Park was established in 1916 and it included Mauna Loa, Kilauea and Haleakala. Later, these were split and Haleakala became its own national park and Mauna Loa and Kilauea became Hawaii Volcanoes National Park. (“Hawaii Volcanoes National Park | History & Facts”) Visitors from all over the world have flocked to this truly magical place to experience first hand the power and awe of these magnificent volcanoes.
Hawaii Volcanoes National Park has two active volcanoes, Mauna Loa and Kilauea, both shield volcanoes. Kilauea erupted continuously for nearly thirty years. It erupted out of two areas in the volcano, the summit of Halema’uma’u as well as in the East Rift Zone Pu’u’o’o. The Halema’uma’u crater collapsed in 2018 due to the lava lake in the summit essentially draining out while at the same time lava started flowing out of the East Rift Zone.
This caused new fissures to be formed and the results were devastating to the surrounding areas. More than 700 structures were destroyed by the flowing lava, many of which were residential homes. (Pappas). What was very interesting about this situation is that it happened very fast and it took everyone by surprise. They were using the best technologies available to monitor the volcano and still no one predicted that outcome.
Volcanoes are both fascinating and terrifying at the same time. You would be hard pressed to find anyone living near an active volcano who isn’t aware of the potential dangers of the area in which they have chosen to live.
People have lived close to volcanoes for hundreds of years and are acutely aware of the inherent dangers of doing so. Besides the obvious of potential lava flow near the active volcanoes in Hawaii other dangers do exist as well. Earthquakes are another potentially devastating side effect and there are hundreds every year in the Hawaiian Islands. These quakes differ from other parts of the world because they aren’t happening due to tectonic plate activity and fault lines. These quakes happen due to volcanic activity stemming from pressure from the lava inside.While most earthquakes in Hawaii are not dangerous they have the potential to be. Other dangers associated with volcanoes are landslides and tsunamis.([No Title]) These hazards have always been a part of living near an active volcano in Hawaii and around the globe.
The islands that make up the state of Hawaii are part of the Hawaiian Emperor Seamount chain. This is made up of many submerged seamounts and islands. This chain was formed by a hotspot in the middle of the Pacific plate. The hotspot, which is where magma rises up from the mantle to the crust, is eventually released into the seafloor where these volcanoes begin to form. As the plate moves very slowly over the hotspot these islands begin to form. (US Department of Commerce, National Oceanic and Atmospheric Administration) . The Big Island in Hawaii currently sits on the hotspot.
The magma from these hotspots is formed in the lowest part of the earth’s crust and in the mantle. Both of these begin in a solid state and when exposed to temperature and pressure form the magma that eventually rises. There are several ways that magma can form. These include decompression melting, transfer of heat, and flux melting. The magma in the Hawaiian islands is formed by decompression melting. This happens through convection , when hot magma rises due to low pressure. The areas of low pressure also have a lower melting point. Higher pressure would, in turn, raise the melting point. When the pressure is reduced, decompression allows the rock in the mantle to start to melt and turn into magma.(National Geographic Society) In Hawaii, this decompression is happening at the mantle plumes. The hot rocks are rising from the high pressure core to the lower pressure areas above. When this happens in the ocean the “hotspots” propel magma on to the ocean floor. They keep growing until volcanic islands form over the course of millions of years. As the plate moves slowly, new volcanic islands begin to form.(US Department of Commerce, National Oceanic and Atmospheric Administration) This is similar to other volcanoes that were created from hotspots. Mountains from Nevada, Idaho and into Yellowstone were formed over a hotspot that is located under the North American plate. The magma pool in Yellowstone is very different from those found in Hawaii. The eruptions here spewed pyroclastic flows with heavy amounts of ash and gas being released into the atmosphere. The lava is very viscous and produces rhyolite or basalt. Due to the hotspot being above land and not deep underwater, the magma pool is much shallower than what is found in the seamounts of Hawaii. (Volcano – Yellowstone National Park (U.S. National Park Service))
The volcanoes in Hawaii Volcanoes National Park are made of a “mafic” magma which means it has low silica content which is somewhere around 50% and it has higher concentrations of magnesium and iron. It has a lower gas content and low viscosity. The temperature of this magma is very high and runs anywhere from 1000-2000 C.(National Geographic Society) All of these characteristics make it a very fluid magma which explodes in a very quick and gentle fashion. These volcanoes erupt two kinds of lava. The first is Pahoehoe which has a smooth, ropy or billowy surface. Aa has a rough, spiny or rubbly surface with a massive interior. The difference in appearance is caused by enclosed gases at the time the lava stopped moving. They both contain identical chemical compositions.(“Hawaiʻi Volcanoes NP”) Mauna Loa and Kilauea are made primarily of tholeiite magma which produces olivine basalt when cooled.(Lavas Erupted at Kilauea Today)
Volcanoes are found on every continent on earth. They remind us that our earth is alive and changing and growing every day. They remind us of the power they hold and the devastation they are capable of producing. They create habitats for flora and fauna that are found nowhere else on earth. The Hawaii Volcanoes National Park inspires wonder and awe to all who visit. It embodies the raw power that our earth holds and reminds us that life is about constant change and growth. The beauty that it holds is sublime and should be preserved at all costs.