USGS: 500 Earthquakes In 24 Hrs, Most Ever Recorded At Kilauea Summit
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Photo: photo: USGS

USGS: 500 Earthquakes In 24 Hrs, Most Ever Recorded At Kilauea Summit


HILO, HAWAII – June 5, 2018

A U.S. Geological Survey official said that the Kilauea volcano in Hawaii was experiencing 500 earthquakes each day.

That figure “is the highest rate ever measured there,” USGS seismologist Brian Shiro told to Big Island Video News in his telephone interview.

“At the summit we have reported no major explosion, large plumes over that day had, however been a lot of earthquakes in fact, so we recorded 500 over the past twenty-four hours which is the highest rate ever measured there. The otherwise the summit activity is rather quiet in terms of the plumes. We think the cause of these earthquakes is continued deflation of the summit from the evacuation of magma under Halema’uma’u crater. Now the effect of this are mostly felt in the immediate area by people in volcano village, in a national park, of course. Of course, another effect is that the Hawaiian Volcano Observatory building itself was damaged and forced us to leave that. So the damage can be quite intense but it's not having a widespreadeffect.”

The floor of Kīlauea Caldera continues to subside as pressure in the magma reservoir decreases in response to withdrawal of magma towards the East Rift Zone. This is the same process that caused the summit lava lake to drop out of sight within the “Overlook vent” inside Halemaʻumaʻu Crater, according to USGS statement.

After each explosion, the faults within and around the caldera are less stressed and, therefore, produce fewer earthquakes. As time goes on, deflation again stresses the faults and the number of detected (and felt) earthquakes increases.

“This pattern of increased earthquake activity really started around May 4th, and it’s gone up and down different times as the pressure has changed in that system. It's around May 27th we have seen a change in the behavior where these steam and ash eruptions are somewhat less regular, and the earthquakes are actually building more, and we're interpreting this currently as rubble, and material that's collapsed in from the walls as choking the conduit, and in a sense suppressing some of the explosions. When the explosions do eventually get out they potentially could be larger, and of course the last three that we had, were the largest yet in terms of energy release, and once associated with the magnitude 5.2, 5.3 as well as 5.4 earthquakes. The system currently is in that state, and we could expect another one anytime,”Shiroexplained.

High rates of earthquake activity were observed during the 1924 summit eruption.Volcano resident Margaret Finch wrote to her father on May 15, 1924, “... and theearthquakes were awful. Some were a slow swaying motion, while others gave you anasty vicious shake. I hate them all. I want to run whenever I feel one. There must be atleast a hundred quakes a day…and probably a great many more than that.”

Brian Shiroadded,“The scenario we have now has many parallels in 1924. It doesn't mean the volcanoes going to follow the same script necessarily, but at least it's a closed guide for us. There definitely could be larger eruptions to come from the summit. We are preparing for that and watching for that. Now in terms of expanding of the Halema’uma’u crater, that's already happening -- pieces are falling off from the walls, you can see it in aerial images from our drones, you can see it from radar imagery from space and it's already gotten larger from this eruption, and there's evidence of slumping along the north-western side where we may expect another collapse to happen. This type of expansion of the crater itself seems to have really taken off again starting after May 27th -- 28th from that time frame when the energy of the explosions correspondingly has increased. So I think that in reflection in part that there are actually removing parts of that crater rim as they release that energy. So is it going to build up to another big one, we don't know, but we certainly have that possibility.”

Author: USA Really