Poas Volcano information
The Poás Volcano, in Spanish Volcán Poás, is an active stratovolcano in central Costa Rica. Poás Volcano has erupted 39 times since 1828.

Apart from the main crater, there are two crater lakes near its summit. The northern lake is known as the Laguna Caliente. It is one of the world's most acidic lakes, with a pH of almost 0, and as a consequence supports little or no aquatic life. Lake Botos, the southern lake, fills an inactive crater, which last erupted 7500BC. It is cold and clear, and is surrounded by a cloud forest located within the Poás Volcano National Park. Poás Volcano is near the epicentre of a 6.1-magnitude earthquake in January 2009 that killed at least forty people and affected nearby towns of Fraijanes, Vara Blanca, Poasito the capital San José and the Central Valley region of Costa Rica.
It also has had eruptive activity in 2009 involving minor phreatic eruptions and landslides within the northern active crater.

Botos Lagoon is a water filled crater in the Parque Nacional Volcan Poas. Its deep blue waters contrast with the dense tropical forest that surround it, making it the perfect spot for the stereotypical Indian sacrifice of throwing a young maiden into the mouth of a crater or a lagoon.

Volcan Poás is one of the most visited volcanoes in Costa Rica, because of its proximity to San Jose and because of the luxuriant forest that surrounds the two craters. The park is just 1 hours drive from San Jose and only 45 minutes from the airport. The park measures 5600 hectares, and this basaltic volcano stands at an altitude of 2708 meters (8,200 feet) above sea level.

The main crater measures 1.5 kilometers across (0.9 miles) and is 300 meters deep (900 feet). At the bottom of this prehistoric-looking hole, there is a medium sized lagoon that spews boiling sulphurous gases. The other crater is the one mentioned above, called Botos Lagoon, contains cold water that connects to the Rio Angel, and later to the large Rio Sarapiqui.

Poás volcano has had a long history of eruptions, going back as much as 11 million years! On January 25, 1910, the volcano spewed out 640,000 tons of ash, and in the period of 1952-1954, it bombarded nearby areas with ash and rocks. Since then, Poás has maintained a low profile, but as recently as 1989, the park was closed because of dangerous sulphurous gas emissions. Its geyser-like eruptions of muddy water and steam, have given it the reputation as the world’s largest geyser.

Most of the people who visit Poás Volcano do not get to see the main crater because of the thick cloud cover that rolls in almost every day. The best time to see the volcano is at 8am when the park opens. The best is to stay in the area and arrive early.