An early morning view of the active domes of Santiaguito volcano, in the foreground, with the remains of Santa Maria volcano in the background. Photo by David Pyle.
Santa Maria volcano is a large volcano in northern Guatemala (Central America) that was partly destroyed in a major explosive eruption in 1902. Since the early 1920’s, an eruption in the crater formed by the 1902 eruption has slowly built up a series of lava flows and lava domes. This eruption is still going today, and this currently active part of Santa Maria volcano is known as Santiaguito.
Geological Setting
Santa Maria is a stratovolcano, at the northern end of the Central American Volcanic Arc, which is an active subduction zone. In this region, the Cocos plate is slowly sinking beneath the Caribbean tectonic plate.
How does Santa Maria stack up as a Top Trumps Volcano?
Last Known Eruption: Continuing eruption (since 1922)
The scores on the cards are based on what we know about the past and continuing activity of Santa Maria.
Explosivity (Volcanic Explosivity Index) – 6. Santa Maria was the location of one of the largest eruptions of the 20th century, in 1902. This eruption effectively destroyed what had been a symmetrical cone, leaving a large crater on the south-western side of the volcano, and depositing ash and pumice many hundreds of kilometres away. All of the eruptions since 1902 have been much smaller than this initial event.
Height – 3772 m. Santa Maria is a classical stratovolcano that rises high above the Guatemalan highlands, close to the city of Quetzaltenango, or Xela. From the top, there are wonderful early morning views down on to the active vent of Santiaguito volcano.
Deadliness. 280. Even though the continuing eruptions of Santa Maria are rather small, there is a continuing and significant hazard from lahars, as the freshly deposited ash and rubble is rapidly washed downstream in rainy-season floods.
Wow factor – 73. Santa Maria is a visually very attractive volcano, and the bonus of being able to see an ongoing eruption from above is quite special.
Unpredictability – 48. In the past hundred years, or so, Santa Maria has been both very active, and has had both large and small eruptions. For this reason, its unpredictability score is quite high.
Devastation Potential – 498. This is a potentially very dangerous volcano, based on the amount of destruction following the 1902 eruption, and the hazard (to local communities, crops and livestock) from ash fallout and lahars from the continuing eruptions remains relatively high.
General Resources about Santa Maria.
Santa Maria is monitored closely by the Guatemalan authorities, and a team of local volunteers, but there is not much material available on the web that describes the general setting of the volcano. The best site that brings information together is Bill Rose’s introduction to Santiaguito Volcano.
Elsewhere, Jessica Ball, who blogs under the name ‘Magma cum Laude‘ has written a few posts on Santiaguito, as this was the volcano where she completed her doctoral research.
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How does the Santa Maria form igneous rocks inside?
The igneous rocks are formed by the eruption of magma, molten rock that originally comes from deep inside the earth, perhaps 60 – 100 kilometres below the volcano. All volcanoes are formed and grow by the eruption of igneous rocks, which sometimes erupt as lava, and other times as ash or pumice.