As of 2017, what was the deadliest volcanic eruption on record?

In 1815, Indonesia’s Mount Tambora erupted. Between 11,000 and 12,000 people were killed by the eruption and the final death toll was more than 71,000 people. Indonesians suffered a second horrendous volcanic eruption in 1883, when Krakatoa blew, killing at least 36,000 people, the second worst total in history.

The ash and gasses from Mount Tambora caused trouble around the world and 1816 was "The Year Without a Summer”. Famine hit as far away as North America and Europe. In 2004, explorers excavated a nearby area that had been buried under 3 meters (10 feet) of matter spewed by the volcano. It is known as Pompeii of the East.

Mount Tambora had erupted three times before 1815, the earliest around 3910 BC. In April, 1815, it rumbled and belched smoke before the April 5 moderate eruption and then detonation. At around 7 p.m. on April 10, columns of fire shot into the sky as the entire mountain became engulfed in lava, which flowed into the town of Tambora, destroying it.

By April 17, the worst of it was over, but the mountain had literally blown its top. Formerly 4,300 meters (14,000 feet) tall, one of the largest in the archipelago of Indonesia, Mount Tambora now stands at 2,852 m (9,300 ft).

Throughout the 19th and 20th Centuries, lava occasionally oozed in and around the mountain. Without explosion, the volcano erupted in 1967. Although dormant, it is not considered extinct, but still, in technical terms, “active”, just not erupting.