Ilopango Volcano | John Seach


El Salvador

13.67 N, 89.05 W
summit elevation 450 m

Ilopango volcano is located on the eastern outskirts of the capital city, San Salvador. The 8 x 11 km caldera is elongated towards the east and filled by a lake.

At least four major eruptions have occurred at the volcano. Deposits from the eruption are found up to 80 km west of the volcano.

1879-80 Eruption of Islas Quemadas
Islas Quemadas domes were erupted in the center of the lake during 1879-80. There is some evidence that the eruption of Islas Quemadas dome in Lake llopango, El Salvador, was affected by solid-earth tides.

1) The first phase of the eruption of Ilopango volcano began with an earthquake swarm on December 20 or 21, 1879 and ended January 2, 1880. On 31st December 1879 a tectonic earthquake caused moderate damage throughout El Salvador and was felt in Guatemala and Nicaragua.

2) Extrusion of a lava dome occurred during the second phase of the eruption at Ilopango volcano. The first period of dome extrusion was accompanied by a rise in the level of Lake Ilopango beginning on 6th January 1880. The second period of dome growth began on 20th January with a large column of black ash and glowing rocks. The dome rose above the lake surface on 23rd January. Dome growth was complete by 3rd February 1880.

3) The third phase of the eruption at Ilopango volcano consisted of three brief episodes of dome extrusion accompanied by violent explosions and rumblings.

450 AD Eruption of Ilopango Volcano
Tierra Blanca Joven eruption was the largest in El Salvador in the past 10,000 years, and one of the largest Quaternary eruptions in Central America. It was equivalent in magnitude to the 1001 eruption of Pinatubo in Philippines. The phreatomagmatic eruptions ejected 18 cubic km of tephra, and covered 10,000 sq km under 50 cm of ash.

The eruption of Ilopango volcano had a major impact on the cultural development of western El Salvador. The affected areas did not recover until the 7th century AD Pyroclastic flows and airfall deposits probably killed every person with an area of 1000 sq km.

Ilopango Volcano Eruptions

1879-80, 450 AD ±30 yr.