Hot water vents at bottom of Ilopango crater lake

To the east of San Salvador lies the crater lake of Ilopango. This large lake fills the crater formed in the 5th century when Ilopango erupted in a cataclysmic event that wiped out Mayan populations and deposited deep ash over much of El Salvador.

A local scuba diving business, Pacific Paradise Divers, recently released this high definition video of what lies below the surface of the volcanic lake. The video reveals hot water vents and the aquatic life around them. The vents are a reminder of the volcanic origins of this beautiful lake.

More on the Ilopango crater From the Smithsonian Institution Global Volcanism Program:
The scenic 8 x 11 km Ilopango caldera, filled by one of El Salvador's largest lakes, has a scalloped 150-500 m high rim. The caldera, which lies immediately east of the capital city of San Salvador, is strongly controlled by regional faults of the central Salvador graben. Four major dacitic-rhyolitic explosive eruptions during the late Pleistocene and Holocene produced extensive pyroclastic-flow and pyroclastic-fall deposits that blanket much of El Salvador. The latest collapse resulted from the massive 5th century CE Terra Blanca Joven (TBJ) eruption, which produced widespread pyroclastic flows and devastated early Mayan cities. Post-caldera eruptions formed a series of glassy dacitic and andesitic lava domes within the lake and near its shore. The Islas Quemadas, a group of low islets in the center of the lake that mark the summit of a largely submerged lava dome, were formed in 1879-80 during the only historical eruption of Ilopango.

Fisherman on Lake Ilopango

Satellite image of Lake Ilopango