Thursday, November 13, 2014

Mauna Loa Priming For Eruption [UPDATED 11/13/2014]

Mauna Loa Priming For Eruption
Hawaii’s largest volcano, Mauna Loa, is priming for eruption according to the Hawaiian Volcano Observatory (HVO). A statement from HVO says the following:

“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

Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.

Monitoring data through the month of September 2014:

Seismicity: Seismicity at Mauna Loa remains elevated in several parts of the volcano. In late September, a swarm occurred to the west of Moku`āweoweo Crater. The swarm had a maximum magnitude of 2.4 and several events that were large enough to be located. In total, there were up to 150 separate earthquakes that were part of this swarm, most too small to be recorded on enough stations to be accurately located, however we infer that their location is similar to the formal locations of the larger events. The same area had a swarm in September and October of 2013. Several long period earthquakes were present at depths from 50 km to the shallow edifice, with most LP earthquakes between 9 and 15 km depth. Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) remain elevated, though similar to the past couple of months. Seismicity rates in the Moku`āweoweo Crater increased over previous months with approximately 50 very small events in the past month at shallow (<5 km) depths. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.

Deformation: On Mauna Loa, GPS data continue to show a broad pattern of displacements suggesting inflation. Preliminary modeling shows the data to be consistent with inflation of one or more magma reservoirs, with the majority of the volume accumulating in a dike-like body beneath the caldera and upper rift zones. Reinflation may have started very slowly in April or May of this year. Displacement rates have been variable, with higher rates in July and August and slowing again in September.”

While this does not mean Mauna Loa is at risk for imminent eruption, it does mean that it is more likely than before. Historically, Mauna Loa is Hawaii’s most active volcano, although it has not had an eruption since its last event in 1984. It had erupted about 33 times since its first documented eruption in 1843. Its eruption in 1984 produced some fast moving lava flows which did cause property damage, and it is likely future eruptions will be similar in style.

At this time, it would be a good idea for islanders to begin seriously preparing for a future eruption. There is no way to tell where an eruption might begin on Mauna Loa, all surrounding areas are at risk. It is interesting that Kilauea still shows no signs of stopping its eruption, as the constant outflow of lava tends to prevent rapid inflation at Mauna Loa, so this could mean Hawaii’s mantle  plume may be getting a bit more active, but that’s just speculation. If it were true, we might expect to see more activity from Loih’i, and possibly Hualai or Mauna Kea (although activity at Mauna Kea is highly unlikely).

*****UPDATE 11/13/2014*****

Mauna Loa continues to inflate. GPS readings show a broad pattern of displacement, and fumerole temperatures are rising at the summit. It is likely the volcano will erupt within the next year or so. The new report from HVO is below:

"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

Seismicity continued to be slightly elevated; deformation patterns may suggest renewed inflation.

Monitoring data through the month of October 2014:

Seismicity: Earthquake rates on the Upper Southwest Rift Zone (Sulfur Cone) remain elevated, though similar to the past couple of months. Seismicity rates in the Mokuʻāweoweo Caldera remains elevated with approximately 40 very small events in the past month at shallow (<5 km) depths. All earthquakes in the past month have been small relative to earthquake sequences observed before eruptions in 1975 and 1984.

Deformation: GPS data continue to show a broad pattern of displacements suggesting inflation. Preliminary modeling shows the data to be consistent with inflation of one or more magma reservoirs, with the majority of the volume accumulating in a dike-like body beneath the caldera and upper rift zones. Reinflation may have started very slowly in April or May of this year. Displacement rates have been variable, with higher rates in July and August, slowing in September and possibly slightly picking up again near the end of October.

Gas: No significant changes in SO2, CO2 were recorded by the Mokuʻāweoweo gas monitor; however, a minor deviation in fumarole temperature was recorded over the past two months. The correlation between fumarole temperature increase, elevated seismic tremor levels, and tilt values reported in September was coincidental. This month, we've continued to record a fairly sharp anomalous 2-3 degree C temperature increase.

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. For 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"

2 comments:

  1. Wow!! There is some crazy things happening on this old Earth! It is scary but very fascinating! I am just learning about Geology and Volcanoes and it is so interesting! I've always been drawn to hot springs and geysers and love roaming around Yellowstone. I think we are in store for a significant event very soon. Have you noticed a correlation between the tropical storms and hurricanes with the location of some of the earthquakes? I find that very interesting too.

    ReplyDelete
    Replies
    1. Any correlation between above-ground weather patterns and tectonic seismicity is purely coincidental. As for large events, check out the eruption in Iceland, which is their biggest since the 18th century eruption of Laki!

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