Posted by: Anna Webb | July 19, 2009

Big Island Volcanic Seismic Activity Diminishes


Mauna Loa: Earth's Largest Active Shield Volcano

Mauna Loa: Earth's Largest Active Shield Volcano

I wrote in a blog earlier in the month about the increase in seismic activity on the Big Island. Within a couple of weeks, earthquakes increased from 30+  and peaked in the 60+ range. Currently the number stands at 36 with only two tiny ones within the last two days.

My friend who lives in Waikaloa mentioned that the vent at the Halema’uma’u crater collapsed and in doing so, the amount of vog/haze in the Waikaloa area has diminished greatly. Such is the ‘ebb and flow’ of Big Island’s volcanic activity – it builds, collapses, then builds again. This constant movement is what keeps the active volcanoes here from building up pressure and “blowing” as there is a constant release of lava and fumes.

Pali at Kilauea in Volcanoes National Park

Pali at Kilauea in Volcanoes National Park

There are 5 volcanoes on Hawaii’s Big Island, 2 are dormant (Kohala and Mauna Kea) and 3 are active (Hualalai, Mauna Loa and Kilauea). Hualalai has not erupted, however, since 1801. Between the late 1700’s and 1801 six different vents erupted on this volcano as lava flowed to the sea along the island’s west coast. It is predicted to erupt again within the next 100 years.

Mauna Kea

Mauna Kea

Mauna Loa is the largest active shield volcano in the world. However, most recent eruptions and the source of most of the volcanic and seismic activity is Kilauea. Lo’ihi is the newest volcano to be formed and is still under the ocean off the southern coast of Hawaii’s Big Island.

Not all seismic activity results from volcanic activity. Since the Big Island is slowly moving northwest following its predecessors in the Hawaiian Islands chain, earthquake activity can result from this movement as well. This “mountain” we call the Big Island is the largest mountain in the world, from the top of Mauna Kea to the ocean floor, and it continues to shift underneath us as it makes its slow journey to the northwest.

In addition, the ring of fire has quieted a bit over the last day after the big 7.8 that rang New Zealand’s bells and created a slight tsunami. New Zealand is anxiously watching it’s plates for more friction and crunching but hopes for it to settle into its new, comfortable position very soon.

Stay tuned to “The Daily Flow” for updates on earthquakes, volcanoes and weather on Hawaii’s Big Island. Comments are always appreciated!

New Zealand Escapes Damage after largest earthquake in 78 years.

http://www.bloomberg.com/apps/news?pid=20601080&sid=ami1GzxoISkk

Big Island Earthquake Map

http://tux.wr.usgs.gov/

Global Earthquake Map

http://www.iris.edu/seismon/

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