The Sciences

Eruption Updates for Hudson, Hierro and Lokon-Empung for October 31, 2011

Rocky Planet iconRocky PlanetBy Erik KlemettiOct 31, 2011 12:56 PM


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A few quick updates on some ongoing eruptions for this last Monday of October. Hudson, Chile

The revived Cerro Hudson in Chile

is still rumbling after ending last week by producing at least three vents

on the ice-covered volcano. The plumes seen last week

(that reached as high as 9 km

) look to be mostly steam from the right two plumes, but the far left still looks to be have some ash (see above) - and the grey on the snow and ice would attest to ash. Now, one question I haven't seen an answer is whether the ash is accidental material coughed up in phreatic (steam-driven) explosions or juvenile (new) magma. At this point, my hunch would be accidental, but I've seen no evidence in either direction. The news this morning suggests the number of earthquakes at Hudson have decreased

, but that could be merely a temporary drop in seismicity - which is why ONEMI has kept the alert status

at Red for Hudson. The exclusion zone for Hudson is currently 45 km

, suggesting that Chilean authorities worry about the generation of lahars/mudflows

from any larger eruption and now 138 people have been evacuated

. El Hierro, Canary Islands.

There was some indication (earthquakes and volcanic tremor) yesterday that magma was on the move under the north side of El Hierro

in the Canary Islands, but nothing came of it even with some larger earthquakes

(approaching M4) shaking the island, but at a depth of ~22 km

. So far, a total of 43 earthquakes have occurred

so far today (October 31) alone. Officials have even gone as far as to say that the current seismicity is not a sign of an impending new eruption

. However, Juan Manuel Santana, Director General of Security and Emergencies said that the new seismicity isn't a risk

to the island and the activity at Hierro is being closely monitored. Images of the eruption from space

can definitely give you an idea how where any potential new land might rise up the new vent (see right) breaks the surface to form a new island

. Lokon-Empung, Indonesia

Not to get lost in the news from El Hierro and Cerro Hudson, last week saw another eruption

at Lokon-Empung in Indonesia (see above). No injuries or fatalities were reported from the eruption. One interesting tidbit

that did come out of an interview from Surono, the head of the Volcanology and Geology Disaster Mitigation Center (PVMBG), was that in Indonesia, each volcanologist is responsible for monitoring 5 volcanoes - a number that could get unwieldy if they are start acting up. As for Lokon-Empung, it appears that the volcano may be entering a pattern of small eruptions

that produce plumes that reach hundreds to thousands of meters, suggesting no real threat right now to the people living near the volcano. However, the Army and the PVMBG is still on alert

to evacuate people, especially those who work in quarries near the volcano, if the eruptions become more intense.

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