Eruptive activity began to wane at the end of last week,with the lava fountains diminishing, then disappearing over the weekend. Views in the webcams showed a steady decrease in activity at fissure 3 over the course of several days.
At this point no lava appears to be emerging onto the surface, with only a few dribbles left in the lava flow to be seen as minor glows across the flank of the mauna.
Oddly Kilauea, after erupting continuously for over a year seems also to have paused. There is no longer any visible lava or even a glow within the Halemauʻmauʻu crater.
On the way home in the eve the red glow dominates the horizon. Going to work the next morning it is the plume on the skyline. The eruption is ever present.
When moving to the island fifteen years ago I had looked at the mauna and thought to myself… One day you will erupt, will it be during my time on the island? This though has occured to me many times in the intervening years… When hiking the lava flows in the saddle, when driving up and down Mauna Kea to work looking across at the many flows streaking the flanks of Mauna Loa. How many times have I looked up and wondered when? One day.
I am not certain what woke me up at one AM, but I was awake. Before going back to sleep I decided to check the satellite photos to see if I might get some telescope time before dawn. But what I found online had me totally awake and grabbing a couple batteries for the camera.
Mauna Loa has awoken.
I was soon driving out from the house to a point above the village with a clear view of the mauna. The whole southern sky an angry red over the village as I drove. I did not have to drive far, just a couple minutes from the house where you can find a clear view. Pulling off I set up the camera and shot.
I was not the only one out, half a dozen cars could be seen stopped along Waikoloa Road to view the eruption. The whole mauna is lit up red and it looks like the west flank is erupting, not just the caldera as Civil Defense currently insists. Just the clouds lit up on that side?
Life is intertesting.
Update: By dawn much of the caldera has flooded with lava. Scale is hard to see in the photos, you have to recall that the caldera is almost two miles across and three miles from end to end.
Update 9:11am: The eruption has already migrated to a series of fissures on the northeast flank. The typical Mauna Loa eruption script is a summit caldera eruption followed by a flank eruption a few days, or a few weeks later. We have just seen that happen in a few hours.
I am including a couple photos here taken by a co-worker as she commuted across the saddle this morning at dawn. You can already see the lava flows making their way into the saddle…
Earthquake activity is on a bit of an uptick around here. While the mag 3.9 that woke us up a few nights ago was probably just a settling event under Mauna Kea, much of the remaining activity is under Mauna Loa. This includes a 3.7 magnitude event last night, part of an ongoing swarm under the long mountian.
Mauna Loa’s activity has remained elevated for some weeks now. There are two swarm centers. One directly under the caldera, but more interestingly a persistent swarm under the northwest flank a few kilometers away.
All of this has the island buzzing with concern. On social media, in the local papers, Mauna Loa is the subject of much speculation. The official line is that no eruption is imminent, but officials are quick to remind residents to monitor local emergency channels and have an evaculation plan at the ready.
Like most armchair volcanologists on this island I have been monitoring Mauna Loa more closely lately. The deformation graphs in particular have been? Interesting. I have even gone so far as predicting that we will not get through the year without a Mauna Loa eruption.
The area of concern has been the western rift zone, exhibiting steady and shallow seismic activity for the last several years. More concerning is the rate of inflation shown in the GPS data, This seems to have doubled in rate around last October.
Then comes today.
An intense seismic swarm is currently occurring beneath the NW flank. Still fairly deep. a few kilometers below the surface, but getting shallower. Magma is definitely moving, a sizable mass moving upwards and emplacing itself higher in the volcano.
This may come to nothing in the near term. Like many seismic swarms it may stop. Just part of the process towards a future eruption some years from now, or never. Or we may be seeing the first step in a new eruption. I will hold to my prediction of an eruption sometime in 2021.
While the beaches may be closed during the pandemic, most of the trails are open. Deb and I did a little walking on the Puʻu Oʻo Trail while coming back over the hill from Hilo.
Nothing unusual to report, no rare native birds. As the ʻōhiʻa are not in bloom few birds were in evidence. Even without blooms or birds this is always a pretty trail, a rugged landscape over recent lava flows and the pioneer plants found on these flows.
Being an inveterate volcano watcher, I have not only been watching the new flow on Kilauea, but keeping a wary eye on Mauna Loa as well. The USGS has steadily been increasing the alert level on this largest of the Hawaiian volcanoes over the last year.
On this unstable rock we live, we get a fair number of earthquakes. Of course not every bump you feel is seismic, sometimes it is just a big truck on the highway. You look on the USGS Recent Earthquakes page anyway, just to see what it was. Not this time, must have been a truck. While I have the page loaded I look about… Wait? What is that cluster on the NW flank of Mauna Loa? I do not remember seeing that before!
For the last year or more there has been a steady cluster of small earthquakes just to the southwest of the main caldera. This notable cluster is usually visible when you stop by the earthquake page and indicates magma motion below the summit. It is a big part of why the USGS has upped the advisory level. The cluster on the west flank looks new to me, a lot of small quakes, some deep, some as shallow as 600m.
I am sure someone over at the USGS is looking at the same cluster and asking the same questions. Maybe they have better answers, but they have not published anything yet. Maybe, like so many times before this cluster will fade away, not to appear again. It is however a reminder that magma is moving down there, the mountain is swelling, someday she will erupt again.
Today I will be driving up and down the mountain. I know I will be looking across the saddle at the looking bulk of Mauna Loa and wondering for the thousandth time. Will I see an eruption from her during my years on island?