Volcanoes
Although people know that volcanoes exist in the United States, few people give much though to the fact that they still erupt. When it comes to volcanoes, only a few places provide a close and dynamic view of volcanic activity. Interestingly, Mauna Loa and Kilauea volcanoes in Hawaii are among the two that offer this view.
These two volcanoes actually erupt quite often although the eruptions are non-explosive. For this reason, scientists have been able to get an “up and close” look at how these volcanoes work. The eruptions associated with Kilauea are monitored very closely. Scientists often describe the volcano’s reservoir as a plumbing system. This relation has been made in direct result from how the volcano behaves during and after the eruption. There continues to be studies of these two volcanoes as well as the surrounding ocean floor as a means of understanding the geologic history. The goal of scientists is to gain more knowledge to identify the hazards associated with these volcanoes and protect the island’s residents.
In fact, most eruptions of Hawaiian volcanoes are non-explosive due to their composition of the magma. The majority of magma that erupts from the Hawaiian volcanoes will form a deep gray to black volcanic rock, also called basalt. Generally, the basalt is in the form of lava flow and once in a while, in a boulder type rock where cinders, ash, or pumice have spit out of the volcano away from the lava flow. The gases found in basalt can escape easily and actually propel the lava high in the air, forming a spectacular found called “curtains of fire.”
The lava, whether erupted in fountains or by a gentle flow, will collect, forming flows that spread along the ground in sheets. The basalt magma fluid is able to travel impressive distances from the vent, which is where the lava breaks the ground and builds the volcano into the shape of an inverted warrior shield, having slopes with a less than 10-degree slope. This type of volcano is called a “shield volcano.”
The volcanoes found in Hawaii will erupt at the summit calderas as well as from the flanks along the linear rift zones, which extend from the calderas. Calderas are the large walled indentions that are formed when the volcano’s summit region collapses. This generally happens after a large eruption. The rift zones are weak areas within the volcano, extending from the surface to several kilometers in depth. If you have not seen a volcano and have a trip to Hawaii on your calendar, take a tour and enjoy the massive natural display of beauty.
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