Restless Bulusan continues to rumble

Look for the answer to MVP #31 later today, but for now, I have a brief update on Bulusan in the Philippines.


We ended 2010 with the restive volcano producing some small explosions of almost entirely old rock from the crater area. Now, this in itself wasn't too hazardous except for people near the summit crater. However, the ash deposits on the slopes of Bulusan could easily be remobilized into lahars that did, indeed, come down the slopes of the volcano. The activity at Bulusan has been very off/on in its nature, with series of what appear to be phreatic (steam-driven) explosions for a few days followed by periods of relative quiet, although clouds have obscured the view of the summit for quite a bit of the last month.

However, it appears that Bulusan is back on the offensive, with a series of new explosions from the summit crater last night (local time). The explosions were heard rather than seen in the towns near the volcano, but PHIVOLCS has said that the explosions where "shallow and hydrothermal in nature", again suggesting that these are steam-driven events caused by magma somewhere in the volcanic edifice heating up the rocks to temperatures that can cause the water percolating into the cracks between the rocks to turn to steam. The steam, of course, expands rapidly and causes the explosion, with the contemporaneous shattering of the old rock in the summit area to produce the ash plume/fall. Monbon, a town near Bulusan, did experience trace amounts of ash fall overnight, the only other direct evidence of the explosive events. PHILVOLCS is maintaining a 4-km exclusion zone around Bulusan as this activity continues, but the alert status remains at level 1.

Top left: Ash plume produced by minor explosions at Bulusan during November 2010.

Related Articles

Scientists discover what caused the worst mass extinction ever

How a cataclysm worse than what killed the dinosaurs destroyed 90 percent of all life on Earth.

Credit: Ron Miller
Surprising Science

While the demise of the dinosaurs gets more attention as far as mass extinctions go, an even more disastrous event called "the Great Dying” or the “End-Permian Extinction” happened on Earth prior to that. Now scientists discovered how this cataclysm, which took place about 250 million years ago, managed to kill off more than 90 percent of all life on the planet.

Keep reading Show less

Why we're so self-critical of ourselves after meeting someone new

A new study discovers the “liking gap” — the difference between how we view others we’re meeting for the first time, and the way we think they’re seeing us.

New acquaintances probably like you more than you think. (Photo by Simone Joyner/Getty Images)
Surprising Science

We tend to be defensive socially. When we meet new people, we’re often concerned with how we’re coming off. Our anxiety causes us to be so concerned with the impression we’re creating that we fail to notice that the same is true of the other person as well. A new study led by Erica J. Boothby, published on September 5 in Psychological Science, reveals how people tend to like us more in first encounters than we’d ever suspect.

Keep reading Show less

NASA launches ICESat-2 into orbit to track ice changes in Antarctica and Greenland

Using advanced laser technology, scientists at NASA will track global changes in ice with greater accuracy.

Firing three pairs of laser beams 10,000 times per second, the ICESat-2 satellite will measure how long it takes for faint reflections to bounce back from ground and sea ice, allowing scientists to measure the thickness, elevation and extent of global ice
popular

Leaving from Vandenberg Air Force base in California this coming Saturday, at 8:46 a.m. ET, the Ice, Cloud, and Land Elevation Satellite-2 — or, the "ICESat-2" — is perched atop a United Launch Alliance Delta II rocket, and when it assumes its orbit, it will study ice layers at Earth's poles, using its only payload, the Advance Topographic Laser Altimeter System (ATLAS).

Keep reading Show less