Tuesday Tidbits: Watching Taal, cooler crater at Ruapehu and swarms in Nevada
Let’s get to some updates on volcanic (or possibly not) rumblings around the world:
Philippines: PHIVOLCS are watching Taal closely, but at least over the last 24 hours, seismicity at the caldera was lower than over the weekend. Instead of the 20+ earthquakes recorded over April 18, earthquakes were down to only 6 in the following 24 hours. This does not mean that the level of danger has been reduced, instead it is likely just the waxing/waning caused by the pulsatory movement of magma under Taal. The president of the Philippines, Benigno Aquino III, has warned the last 1,000 people staying on Volcano Island to be prepared to leave after Gen. Benito Ramos, the chief of the National Disaster Risk Reduction and Management Council, told the president that the volcano could erupt at any time. However, Ramos also claimed that the remaining people on the island could be evacuated in 30 minutes if need be. The government is taking no chances, with supplies and equipment ready for a potential larger evacuation.
New Zealand: It seems that Ruapehu is also calming down after signs of heightened activity. The Crater Lake at the summit of the volcano had seen an increase in its water temperature to the highest since the lake returned in 2002 – almost 40C. The latest temperature of the lake water are back down to 33C, however GNS Science has kept the aviation alert for Ruapehu at Yellow until this cooling trend is observed for a longer period. Ruapehu is also getting some additional monitoring, namely a high speed Doppler radar that will be able to watch for small (and large) ash plumes and explosions from the crater.
Nevada: I know many of you have been watching the earthquake swarm near Hawthorne, Nevada with some interest. There have been over 400 earthquakes near the Nevada town over the last few weeks and no one is quite sure what the source of the seismicity might be. There is the interesting coincident that the focus of the swarm is near the Aurora Volcanic Field – however, Graham Kent from the director of the Nevada Seismological Lab at the University of Nevada, Reno, doesn’t think a volcanic eruption is likely (note: the Nevada TV station for this link decided to post video from “Volcano” with the story…sigh.) Even if there was an eruption, it would likely be something small, such as a small cinder core or fissure lava flow based on the previous activity at the Aurora Field, which hasn’t been active for 250,000 years. However, that being said, Nevada is still a volcanically-active state, with a number of locations that could see new volcanic activity. Also, Nevada has seen many earthquake swarms over the past few years, and none have lead to volcanic activity – that is like in the Basin and Range province.
Top left: The steaming Crater Lake at Ruapehu in an undated image (not recent). Click here to see the original image.