Thursday, September 24, 2015

Mauna Loa Aviation Code Raised To Yello

Mauna Loa has been slowly re-loading its vast magma chamber since it's last eruption ended in 1984. In the mid-2000's, inflation increased, stopped, started again, and now continues at a slow pace. I've been covering the goings-on at Mauna Loa and have suspected for a while it was getting ready for its next round, but as of yesterday, HVO has taken notice as well and chose to raise the aviation code (not the alert code) to Yellow (advisory).

Mauna Loa has been experiencing tremor and seismicity associated with small rock-fracture events for some time now, but I suppose it's gone on long enough where HVO is now starting to get nervous. Mauna Loa is after all, the largest active shield volcano on earth by both volume and height, and given the types of eruptions it has, people on the Big Island of Hawaii have a reason to be nervous.

Nearly all of the recent eruptions of Mauna Loa have produced enough fast-moving pahoehoe lava to reach the shore. Many towns have been paved over in the past, and due to Mauna Loa's size, the lava can move at much faster speeds than the lavas produced by its neighbor to the SE, Kilauea.

Mauna Loa's re-inflation and increased seismicity is still below the levels that preceded the last two eruptions, so an eruption is by no means imminent at this time. That can change without warning, however, this is a heavily monitored volcano, so it's likely there will be at least several hours of warning prior to any eruptive activity.

One theory currently is that due to Kilauea's ongoing eruption (which has continued nonstop since 1983), the magma reservoirs at Mauna Loa take a bit longer to refill, as both volcanoes have the same magma source - a giant magma hotspot that is responsible for the creation of all Hawaii's island chain. So it is possible that the release of lava from Kilauea is keeping Mauna Loa from rapidly inflating like it did in the past.

If that were true, it might explain why inflation is not as rapid, and seismicity is not as intense. Only time will tell. Previously, Mauna Loa had typically erupted before Kilauea, so the fact that Mauna Loa is inflating while Kilauea is erupting could indicate higher plume pressure on the island. Again, far too soon to tell, but it does make a lot of sense.

I've been monitoring Mauna Loa since 2008, and this is the first time that HVO has raised the alert level in a long time. It's worth keeping your eye on the Big Island, and if you live there, be vigilant and stay up to date, as this volcano, once it starts erupting, is capable of issuing lava flows that travel upwards of 60mph. 

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