Kilauea Calms Briefly While Merapi in Indonesia Erupts Anew

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A USGS scientist measures the temperature of gases emitted from a fissure at Leilani Estates on May 9, 2018. USGS/HVO.

The eruptions at Kilauea took a bit of a break over the last day — at least at the surface. The fissures that opened in Leilani Estates (see above) haven’t erupted much new lava, but the are still emitting copious amounts of volcanic gases like sulfur dioxide. So, right now, that is the biggest hazard for people on the east side of the big island: the threat of volcanic fog, or vog. The mixture of water and sulfur dioxide makes acid, which can then irritate eyes, nose, mouth and lungs (at best) and cause extreme respiratory distress and death (at worst).

However, as with most volcanoes, the real action to watch is happening underground. Earthquakes continues under the Puna area where the fissures opened and there is some indication that magma could be moving further down the East Rift zone, so the potential for eruptions to the northeast of Leilani Estates might be increasing. So far, this eruption has covered over 115 acres of land in and around Leilani Estates and destroyed at least 35 structures (mainly homes), displacing thousands of residents. UPDATE 12:15 pm EDT May 10: Here are some more details on the current assessment of the situation by the scientists at the Hawaii Volcano Observatory:

This is all happening at the same time as the summit lava lake at Halema’uma’u is continuing to drop (see below), so the chances of potential steam-driven explosions at the summit might be increasing. The main cause for those explosions would be pressure building after rock falls choke  in the conduit that feed the lava lake, along with some mixing of lava and water to increase the explosiveness. All of this is happening because now the lava lake level will be below the water table, so water can directly create more steam in the conduit and interact with the lava. This potential for an explosive eruption has prompted a total closure of Hawaii Volcanoes National Park.

So, the situation at Kilauea is very much a waiting game: will the Leilani Estates fissures start up again? Will eruptions move to the northeast? Will steam-driven explosions start at the summit of the volcano? The chances are there for all of these event, but only by closely monitoring the earthquakes, gases and inflation at Kilauea will the HVO scientists how those chances might be changing. If you need to catch up on all the events of this Leilani Estates eruption, HVO posted a list of everything that has happened over the past few weeks,.


Meanwhile, in Indonesia, another volcano is experiencing steam-driven explosions: Merapi. The volcano whose 2010 eruption caused killed over 350 people produced a phreatic blast today that reached 5.5 kilometers (18,000 feet). As I’ve mentioned before, these steam-driven blasts don’t have much in the way of precursors, so it was lucky no one was harmed in this explosion, although 120 hikers had to be rescued and thousands did evacuate. Video of the eruption (see below) shows some small pyroclastic flows towards the summit of the volcano.

The airport in Yogyakarta was also closed briefly due to the ash. The question that Indonesian volcanologists will be trying to answer now is if this is a sign that Merapi might be reawakening for the first time since its eruptions in 2014 or merely a one-off eruption triggered by groundwater getting deeper into the summit rocks.

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