It took the two geologists and their colleagues at USGS 35 years to produce the Lassen maps. "We've been on top of every bloody peak out there," Muffler said. Age-dating techniques developed in the 1990s enabled the scientists to calculate more precisely how long ago eruptions occurred at various locations in the park.
They've also been able to trace the outlines of the mother of all Lassen volcanoes, the massive Brokeoff Volcano, which dominated the Lassen skyline some 600,000 years ago the same way Mt. Shasta does in its own region today. Over the years Brokeoff was worn down by water and glacial erosion.
The park's current star volcano, Lassen Peak, last erupted in 1915, drawing attention to the volcanic region and spurring its designation the following year as a national park.
Lassen National Park offers "the most spectacular array of thermal features in the Cascade Range," according to the pamphlet that accompanies the new maps. Those spectacular features include the fumaroles, bubbling mud pots, and a boiling lake, Boiling Spring Lake — all evidence of the intense thermal activity just under the surface.
READ MORE:
http://www.redding.com/news/2011/aug/27/men-map-lassens-volcanoes/
RELATED:
http://www.nps.gov/lavo/naturescience/eruption_lassen_peak.htm
READ MORE:
http://www.redding.com/news/2011/aug/27/men-map-lassens-volcanoes/
RELATED:
http://www.nps.gov/lavo/naturescience/eruption_lassen_peak.htm
On May 22, 1915, an explosive eruption at Lassen Peak, the southernmost active volcano in the Cascade Range, devastated nearby areas and rained volcanic ash as far away as 200 miles to the east. This explosion was the most powerful in a 1914-17 series of eruptions that were the last to occur in the Cascades before the 1980 eruption of Mt. St. Helens. Lassen Peak is the largest of a group of more than 30 volcanic domes erupted over the past 300,000 years in Lassen Volcanic National Park.
