Eruption of Mount Marapi: Mount Marapi, a complex volcano on the Indonesian island of Sumatra, erupted. Between 80 and 100 people were killed.

On 30 April 1979, Mount Marapi, a complex volcano on the Indonesian island of Sumatra and the most active complex volcano in West Sumatra province, erupted, killing between 80 and 100 people.

The Marapi, or Mount Marapi, is a complex volcano in West Sumatra, Indonesia, and is the most active volcano in Sumatra. Like that of its quasi-homonym on Java, its name means "Mountain of Fire". Its elevation is 2,885 metres (9,465.2 ft). Several cities and towns are situated around the mountain including Bukittinggi, Padang Panjang, and Batusangkar. The volcano is also popular among hikers.

A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. They may form due to changes in eruptive habit or in the location of the principal vent area on a particular volcano. Stratovolcanoes can also form a large caldera that gets filled in by a lava dome, or else multiple small cinder cones, lava domes and craters may develop on the caldera's rim.

Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian and Pacific oceans. Comprising over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guinea, Indonesia is the world's largest archipelagic state and the 14th-largest country by area, at 1,904,569 square kilometres. With over 280 million people, Indonesia is the world's fourth-most-populous country and the most populous Muslim-majority country. Java, the world's most populous island, is home to more than half of the country's population.