* Astronomy

Can volcanoes trigger ice ages?

The idea that a super-enormous volcanic eruption - or hypereruption - would alter the climate dramatically has been around for a long time. It fits the facts about the biggest historical eruptions we know of, and also our understanding both of how volcanoes work and how the atmosphere works. But could the drama extend to tipping the climate from an interglacial state to a full-blown ice age?

The answer, as has long been believed, is still No, according to Alan Robock and colleagues in a paper published last year.
Read more

When volcano seismologist Stephen McNutt at the University of Alaska Fairbanks's Geophysical Institute saw strange spikes in the seismic data from the Mount Spurr eruption in 1992, he had no idea that his research was about to take an electrifying turn.

"The seismometers were actually picking up lightning strikes. I knew that I had to reach out to the physicists studying lightning" - Stephen McNutt.

Read more

Title: Cold Decade (AD 1810-1819) Caused by Tambora (1815) and Another (1809) Stratospheric Volcanic Eruption
Authors: Jihong Cole-Dai, David Ferris, Alyson Lanciki, Joël Savarino, Mélanie Baroni, Mark H. Thiemens

The extremely cold temperatures during the latter part of the decade from 1810 to 1819 - the coldest decade on record during the past 500 years - have been attributed mainly to the enormous 1815 eruption of the Tambora volcano in Indonesia. Such large volcanic eruptions cool the planet by spewing ash and gases into the stratosphere, where they form sulphate aerosols that block sunlight. But what accounts for the abnormally chilly temperatures earlier in the decade, between 1810 and 1815? Some recent studies have suggested that an unrecorded large volcanic eruption occurred around 1809. To investigate further, Cole-Dai et al. analyse ice cores from Greenland and Antarctica. In the 1809-1810 snow layers, the authors find anomalous sulphur isotopes that must have resulted from chemical reactions that could only have occurred in the stratosphere following a very large volcanic eruption. The results, which help improve understanding of volcanoes' effects on climate, provide the first compelling evidence that an unknown large volcanic eruption occurred in the tropics in early 1809 and contributed to the coldest decade in recorded history.

Read more (Subscription, PDF)

Deep structure imaged under Hawaii

Geologists have obtained the best image yet of a plume of hot rock that rises from Earth's deep mantle and fuels the volcanoes of the Hawaiian islands.
Read more