El Chichón Volcano - John Seach


Chiapas, Mexico

17.33 N, 93.20 W
summit elevation 1060 m
Lava domes

El Chichon is an andesite stratovolcano of Quaternary age situated in forested terrain of north-central Chiapas, Mexico. It is the youngest volcano in the northwestern part of the 150-km-long Chiapanecan volcanic arc.

El Chichón volcano has produced at least 12 major volcanic eruptions during the past 8000 years. The volcano displays a recurrence interval of 300 years on average, with a range from a minimum of 100 yr to a maximum of 600 yr.

The nearest cities of substantial size are Villahermosa, 80 km to the north northeast, and Tuxtla Gutierrez, 70 km to the south-southeast. The nearest neighboring Holocene volcanoes are about 275 km and 200 km to the southeast and northwest, respectively.

1982 Eruption
El Chichon Volcano erupted on 28th March 1982 after several months of increased seismic activity. This was the first historical eruption at the volcano. From 29th March to 4th April 1982 three large explosive eruptions occurred at El Chichon volcano. The 1982 eruptions produced a 1 km wide crater which now contains a lake. Nearly all of the pre-1982 summit dome was destroyed during the eruptions, and created a 1 km wide and 300 m deep crater in its place. The eruptions killed between 1700 and 2300 people, made more than 20,000 homeless and caused severe economic damage, mostly from cattle stock loss, and extensive damage to the coffee, cocoa and banana plantations.

1st Eruption
The first eruption occured on 28th March 1982. It was a 6 hour Plinian
event. It produced an eruption column which reached an altitude of 20 km.

2nd Eruption
After five days of minor phreatic and phreatomagmatic eruptions, a second major eruption began on 3rd April and lasted about 4.5 hours. Pyroclastic surges traveled up to 8 km from the crater. A Plinian eruption column developed after the surges, and reached an altitude of 24 km. This stage was the most energetic of the eruption, and produced an average mass eruption rate was three times that of the Mt St Helens eruption rate in 1980. Column collapse produced a second pyroclastic surge which covered an area of 104 sq km.

3rd Eruption
The third eruption began on 4th April and lasted for 7 hours. The
Plinian eruption column had an average height of 22 km and produced 0.40 cubic km of tephra. Column collapse produced a small surge which covered an area of 39 sq km.

Crater Lake
A crater lake formed in the 1km wide crater of El Chichón volcano after the 1982 eruption. The crater lake formed during the June–November 1982 rainy season. The lake is very shallow, with a depth of 1-3 m. It is essentially a large steam-heated pool, where the acidity is provided by the oxidation of hydrogen sulphide. The lake has a pH 2.2 and temperature of 30 deg C.

1930 Fumarolic Activity
El Chichon Volcano was climbed by Friedrich Mullerried in 1930 and noted the presence of vigorous fumaroles, solfataras and hot springs. He speculated that El Chichon might erupt in the future because of fumarolic activity and earthquakes.

El Chichón Volcano Eruptions

1982, 1360 ± 100 years, 1190 ± 150, 780 AD ± 150, 590 AD ± 100, 480 AD ± 200, 190 AD ± 150, 20 BC ± 50, 700 BC ± 200, 1340 BC ± 150, 2030 BC ± 100, 6510 BC ± 75.