The Masaya Volcano is one of the most active volcanoes you are going to find in Nicaragua. It is situated some 20 kilometers to the south of the capital city of Managua, Nicaragua. The Masaya Volcano is a shield volcano and it also happens to be located in the first and largest National Park of the 78 protected areas in Nicaragua.
The Masaya Volcano isn't really a solitary volcano. It is a composition of many different aspects such as calderas and craters, and other volcanoes. The largest of the volcanoes which make up the Masaya Volcano is the Las Sierras shield volcano and caldera. Within this bigger caldera is actually what is known as the Masaya Volcano, so remember that as you are staring in awe at a huge crater, and remember that you are actually standing inside another crater of an even larger volcano!
The Masaya Volcano is composed of two different cones which are still active, in fact the most active of all the volcanoes you can find in Nicaragua. The two cones are known as the “Masaya” and “Nindiri” cones. These cones are constantly changing and shifting, due to the active nature of the Masaya Volcano.
The floor of the Masaya caldera is covered in sparse vegetation which indicates that the lava there has resurfaced as recently as 1,000 years ago. However, there have only been two different lava flows which have erupted since the 16th century. The first such lava flow was in 1670, and was an overflow of lava from the Nindiri crater. The Nindiri crater at the time was a 1 kilometer wide lake of roiling, boiling, blisteringly hot, lava. The other lava flow occurred circa 1772, and made its way down the side of the Masaya cone. Since 1772, lava and magma flows have appeared only in the Santiago pit crater. This crater is the most active to date, and is constantly billowing sulfur and other hot gases.
The Masaya Volcano is constantly spewing out huge quantities of sulfur dioxide gas, which comes from the Santiago crater, and volcanologists are currently studying these emissions, among other things, to help and better understand the sometimes erratic goings on in the Masaya Volcano and to help better understand just what the impact has on things such as acidic rain, and other potentially harmful effects on the local environment.
Even though Masaya Volcano is relatively inactive to the naked eye, that is not to say that it is not doing anything. In fact, just the fact that it is degassing on a regular basis suggests that there are large forces at work deep inside the volcano, away from our prying eyes. Some people fear there is going to be another eruption event from the volcano, and the volcano has been closed to tourists time and again due to this fear. Even today, if you happen to make your way to see this marvel of nature, you are required to park your cars pointed downhill, should the need arise to make a quick getaway.