Activity at Colima, Mexico has continued over the last several weeks. Ash eruption plumes topping out at around 5 km along with lava block avalanches have been observed. The output of this volcano is primarily andesitic with lava domes and flows. The domes are periodically destroyed with explosive outbursts. http://www.ssd.noaa.gov/VAAC/messages.html
The most recent blast was caught on camera this week. http://www.bbc.com/news/world-latin-america-31505368
Colima Volcano stands some 2,700 m above the surrounding land and is topped with a prominent crater / caldera. It occupies a caldera of the Paleofuego volcano which is its predecessor. There are also several domes on its flanks from eruptions in the 19th Century.
Around 300,000 live within some 40 km of the volcanic complex.
Colima Webcam of the Jan 22, 2015 explosion:
The Colima Volcanic Complex sits near the western edge of the Trans Mexican Volcanic Belt. It consists of overlapping remains of at least three cones and remains of cones and measures roughly 25 km in diameter. Activity in the complex is driven by complex subduction of the Cocos Plate with a trench some 150 km southeast. The thing that makes the area complex is a junction between the northwestern corner of the subducting Cocos Plate and the smaller Rivera Plate also subducting to the east. This junction creates a system of grabens which Colima straddles.
The Colima Volcanic Complex sits at the eastern edge of what is known as the Jalisco block, which is part of the North American Plate. There is a spreading rift called the Colima rift through which the magmas are erupted. It runs roughly north – south along the boundary of the block. The block is constructed mostly by the Puerto Vallarta batholith. The paper I reviewed did not believe the activity of this block was being driven by the subduction processes, though the andesitic eruptive products most certainly are subduction related.
The three cones are oriented roughly north to south, with activity moving south by around 20 km over its lifetime. The three cones are Cantaro, Nevado del Colima, Paleofuego and Colima. Colima is the most active volcano in Mexico today. http://www.geo.mtu.edu/EHaz/ConvergentPlatesClass/Delgado/01_SPE422_06%20Macias%20GSA%20Special%20paper.pdf
Cantaro began some 1.6 MY ago and ended some 1.0 MY ago. It is primarily andesitic lava flows followed by dacitic domes, indicating explosive activity.
Activity migrated south some 15 km with the growth of the next vent, Nevado del Colima which was a prolific stratovolcano that began erupting some 600,000 years ago. Eruptive history has been divided into multiple phases. Activity from Nevado has multiple instances of flank collapse, debris flows, associated pyroclastic deposits, and rebuilding of the edifice before activity ceased some 2000 years ago.
Debris flows from Nevado include one around 18,500 years ago that covered some 2,200 km2 with an estimated 22 – 33 km3 of debris. Some of the andesitic lava flows are on the order of 20 km long. Each debris flow created the typical Mount Saint Helens amphitheater horseshoe kilometers across pointing in the direction of the flow. Tephra and ash deposits from Nevado are thought to be in excess of 300 km3 for the first phase of growth of this mountain alone.
There were a series of plinian eruptions between 8,000 – 2,000 years ago that refilled the caldera with pyroclastic and andesitic lava flows. One paper suggests that Nevado collapsed as many as 12 times over the last 45,000 while the Paleofuego / Colima edifice has done the deed perhaps as many as nine times since eruptions started from it.
There is some confusion among the papers about the formation of Colima, the newest vent. Some papers break its formation into two parts – Paleofuego and Colima. Paleofuego is formed first and destroys its cone. Colima then rebuilds in the caldera. Others refer to the older structure as Colima. This is similar to the nomenclature that has the Soma Caldera as a separate entity than Vesuvius which grew through it.
Paleofuego is a new vent that began during the latter stages of Nevado activity. It is a 5 km wide caldera that suggests it began as another 4,100 m high stratovolcano. Pyroclastic flows from this vent have been dated to 38,400 years ago. Like Nevado, this vent alternated between cone building, cone collapses, lateral blasts and caldera / amphitheater formation. The youngest debris flow from this volcano covered some 1,200 km2. It is thought to date either 9,400 or 4,300 years ago and ejected some 6 – 12 km3 of debris. Total coverage from this volcano is thought to be some 5,000 km2.
Following the last collapse of Paleofuego, activity migrated to the south in the floor of the caldera. This activity formed the modern Colima. The youngest deposit from Paleofuego is dated some 2,500 years ago.
The modern Colima is composed out of layers of andesitic lava, ash and pyroclastic deposits. It has been a very active vent, with some 43 known eruptions over the last 400 years. Pyroclastic flows from Colima have traveled some 15 km from the center of the volcano. Total volume of these flows were just over 1 km3.
The largest recent eruption of Colima was 1913 which created the 15 km long pyroclastic flow.
Colima is a very active volcanic center that has a history of significant eruptions in the not so distant past. Given the tectonic rifting that appears to be driving its activity and the continuing subduction melt feeding it, I would expect continuing activity, some of it violent and extensive in current and future years. The 300,000 some people who live within 40 km of this volcanic complex should be very practiced in emergency planning and disaster mitigation.
POLL IS CLOSED – thank you all!
Our poll closed with 132 voters as follows:
Volcano Hotspot: 82 votes = 62%
Volcano 360: 34 votes = 36%
Other: 16 votes = 12%
The additionally suggested names were:
Magmacious – volcan in live – Lava Bar and Grill – VolcanoSpot – The Magmarium – Lava Love – savage volcano garden – Magma Musings – OCD – Volcanoholics – The Magma Chamber – Volcano Chamber – Porn – mind eruptions volcano blog – Volcanoes 24/7 – magma musings.
Thank you for those as well but, alas, none of them knocked our socks off…
So the winner is…
Every weekend, we will have riddles for your entertainment. Check the side bar for the link to this week’s riddles. Answers posted in the main thread do not count; they must be posted in the riddle thread. Head on over and have some fun! This week’s riddles are as follows:
Brain food: (all are volcanoes or volcanic features)
1. The image minus 52.
2. This one is a warning from a famous cook.
3. The most recent eruption site on an island known for its caper festival.