The Arenal Eruption of 1968

The fateful day was July 29th, 1968. The people of La Fortuna were kept up the night before with intense tremors from the build-up of seismic activity. At 7:30 AM the first explosion formed three new craters in the cone-shaped volcano.

Before that fateful day, during which as many as 500 people died, the Arenal Volcano was called Cerro Arenal (or Mount Arenal), because it was not seen as an active volcano. The entire volcano was covered in thick vegetation, concealing the ardent fury that lurked beneath Arenal's benign exterior. That is not to say, however, that the local people had no idea of Arenal's volcanic activity. Before the 1968 eruption, hunters would often spend the night at the top of the then Cerro Arenal, or Mount Arenal, because the rocks would emit heat, giving the men a comfortable reason not to make the long trek down the mountain the same day. I don't know to what extent they understood the implications of these hot rocks, but it certainly wasn't compelling enough to leave the area.

On the day of the eruption, the three craters, A, B, and C, (in ascending order up the side of the volcano) formed on the west side of Arenal. Lava flows devastated a twelve-square-kilometer area west of the volcano and the eruption spread volcanic ash that reached Santa Cruz, Guanacaste. Also, large rocks were hurled from the volcano, traveling several kilometers to make craters as big as 20 meters wide and 3 meters deep.

The Arenal Volcano has been erupting daily since 1968, often spewing out lava, much to the delight of observers in La Fortuna. Most of the activity has moved to the highest crater, crater C, which is constantly building more and more height to the structure of the volcano. Due to lava flows from crater C, the Arenal Volcano grows several meters in height every year.