Arenal Volcano

As a geologist, I can not describe how excited I am to see the Arenal Volcano up close and personal. Being able to see flowing lava will be a first for me. I have been twice to Mount St. Helens in Washington State, a volcano that erupted in 1980, spewing an ash cloud that extended across much of the Northern plains of the U.S. and was detected in trace amounts around all around the northern hemisphere. My first visit was in the early 1990's. Logging trucks were still clearing away trees from the surrounding countryside that had been downed by the volcano's horizontal blast (see video below.) I visited again in 2005. This time there were no more logging trucks, but instead smaller plants and grasses had begun to regrow around the volcano's vacinity, the first step to replenishing the once fertile soil that covered the region.



Both Arenal and St. Helens are known as stratovolcanoes. Stratovolcanoes are cone shaped volcanoes that have alternating periods of large explosive eruptions and lengthy, more slow flowing eruptions. Mount St. Helens is currently in a quiet period, with pressures slowly building underneath the surface. A year ago St. Helens experienced a minor eruption relieving some of the building pressure without a giant explosion. Arenal's current eruption has been going since 2000, when a violent eruption destroyed some nearby villages and even killed some natives before the eruption took on its more quiescent nature of today. Both volcanoes are along the Pacific "Ring of Fire" and are a result of subducting oceanic crust underneath the North American continental plate. See clips of the erupting Arenal Volcano in the video below.