Wednesday, June 18, 2014

Is Mauna Loa Rumbling Back To Life?

Recent quake activity within the Mauna Loa volcanic system on the Big Island of Hawaii has some scientists and spectators wondering if Mauna Loa could be gearing up for another eruption in the near future. Many small quakes have been recorded under the summit and rift system lately, however this does not mean an eruption is imminent. While gradual inflation of the volcano has been occurring since 2010, the volcano is not displaying any signs typical of the volcano gearing up for an eruption, such as drastic inflation, changes in fumerole temperature, or large, rock-fracture quakes associated with magma rising through the crust.

But that really could change at any moment...

The main thing that would prevent an eruption of Mauna Loa is the fact that Kilauea is still highly active, and venting lava every day. This releases some pressure on the magma chamber of Mauna Loa, but deep down, the volcanoes are in fact linked at the magma source. If the magma plume exceeds what Kilauea pumps out, which is probably what's occurring slowly, Mauna Loa would experience refilling of its massive magma chamber, and slowly prime for an eruption.

Mauna Loa is one of Hawaii's most active volcanoes aside from Kilauea and Hualei (which last erupted in 1801), having last erupted in 1984 simultaneously with Kilauea who's 1983 eruption is still ongoing to this day. Typically Mauna Loa has erupted every several decades, and some volcanologist are of the mind that it is 'overdue' for an eruption - however volcanoes are never on a 'schedule', and statistical data for their eruptive periods is nearly useless.

There is no telling when Mauna Loa might actually erupt. Despite many efforts by the scientific community to accurately forecast volcanic eruptions months, or even years in advance, the technology and methodology simply has not coalesced yet. While it is easy to warn of an imminent eruption for most volcanoes a few hours before the activity increases (or at the very least, raise alert levels on restless volcanoes), forecasting an eruption from a volcano like Mauna Loa, which is one of the best studied volcanoes in the world, is still decades away at best.

HVO for now is keeping it's head cool and issued the most recent report on Mauna Loa:

"MAUNA LOA VOLCANO
(VNUM #332020)  19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

No significant changes were recorded through May 2014.  Seismicity: Seismicity continued to be elevated over the average rates of the past 25 years-12 shallow events below summit area, 7 events to the west of Moku`āweoweo Crater (<13 km), 5 events to the north of Moku`āweoweo Crater, 17 shallow events on the Upper Southwest Rift (Sulfur Cone), 2 shallow events on the Lower Southwest Rift, 2 shallow events on the NE Rift Zone.  

Deformation: GPS and tilt networks did not record any changes in deformation rates or patterns that were significantly above the error of the measurements during May. Southeasterly motion of the south flank continued.  Gas: No significant changes in SO2, CO2 were recorded by the Mokuaweoweo gas and temperature monitors in May. Daily average fumarole temperature during the month declined from 76 to 75 degrees C, still not back down though to the 71.7 degrees average of several months ago.  

Background: Re-inflation of Mauna Loa's shallow magma storage reservoirs started immediately following the most recent eruption in 1984, then turned to deflation for almost a decade. In mid-2002, inflation started again, just after a brief swarm of deep long-period (LP) earthquakes. A more intense swarm of several thousand deep Long Period (LP) earthquakes occurred in late 2004, immediately preceding a dramatic increase in inflation rate. Inflation slowed again in 2006, ceased altogether in late 2009, and resumed slowly in late 2010.  Rising gradually to more than 4 km above sea level, Mauna Loa is the largest active volcano on our planet. Its long submarine flanks descend to the sea floor an additional 5 km, and the sea floor in turn is depressed by Mauna Loa's great mass another 8 km. This makes the volcano's summit about 17 km (56,000 ft) above its base!

The enormous volcano covers half of the Island of Hawai`i and by itself amounts to about 85 percent of all the other Hawaiian Islands combined.  Mauna Loa is the largest active volcano on Earth and is among Earth's most active volcanoes, having erupted 33 times since its first well-documented historical eruption in 1843. Its most recent eruption was in 1984. Fore more information on Mauna Loa, see the USGS Fact sheet available at http://pubs.usgs.gov/fs/2012/3104/fs2012-3104.pdf.   CONTACT INFORMATION: askHVO@usgs.gov  The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i."

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