Izalco is a stratovolcano on the side of the Santa Ana Volcano, which is located in western El Salvador. It is situated on the southern flank of the Santa Ana volcano. Izalco erupted almost continuously from 1770 (when it formed) to 1958 earning it the nickname of "Lighthouse of the Pacific", and experienced a flank eruption in 1966. During an eruption in 1926, the village of Matazano was buried and 56 people were killed. The formation of the volcano actually occupied highly arable land on the southern slope of the Santa Ana volcano which was used for the production of coffee, cacao and sugar cane
A stratovolcano, also known as a composite volcano, is a tall, conical volcano built up by many layers (strata) of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic explosive eruptions and quiet eruptions, while there are some with collapsed craters called calderas. The lava that flows from stratovolcanoes typically cools and hardens before spreading far due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as 15 km (9.3 mi).
Stratovolcanoes are sometimes called "composite volcanoes" because of their composite layered structure built up from sequential outpourings of eruptive materials. They are among the most common types of volcanoes, in contrast to the less common shield volcanoes. Two famous stratovolcanoes are Krakatoa, best known for its catastrophic eruption in 1883 and Vesuvius, famous for its destruction of the towns Pompeii and Herculaneum in 79 AD. Both eruptions claimed thousands of lives.