The first English-language paper on the subject was published in 1947 by William Henry Mathews, describing the Tuya Butte field in northwest British Columbia, Canada. The eruptive process that builds these structures, originally inferred in the paper, begins with volcanic growth below the glacier. At first the eruptions resemble those that occur in the deep sea, forming piles of pillow lava at the base of the volcanic structure. Some of the lava shatters when it comes in contact with the cold ice, forming a glassy breccia called hyaloclastite. After a while the ice finally melts into a lake, and the more explosive eruptions of Surtseyan activity begins, building up flanks made up of mostly hyaloclastite. Eventually the lake boils off from continued volcanism, and the lava flows become more effusive and thicken as the lava cools much more slowly, often forming columnar jointing. Well-preserved tuyas show all of these stages, for example Hjorleifshofdi in Iceland.Products of volcano-ice interactions stand as various structures, whose shape is dependent on complex eruptive and environmental interactions. Glacial volcanism is a good indicator of past ice distribution, making it an important climatic marker. Since they are embedded in ice, as glacial ice retreats worldwide there are concerns that tuyas and other structures may destabilize, resulting in mass landslides. Evidence of volcanic-glacial interactions are evident in Iceland and parts of British Columbia, and it is even possible that they play a role in deglaciation.
An important measure of eruptive strength is the Volcanic Explosivity Index an order-of-magnitude scale, ranging from 0 to 8, that often correlates to eruptive types

Eruption mechanisms
Volcanic eruptions arise through three main mechanisms:
Gas release under decompression, causing magmatic eruptions
Ejection of entrained particles during steam eruptions, causing phreatic eruptions
Thermal contraction from chilling on contact with water, causing phreatomagmatic eruptionsThere are two types of eruptions in terms of activity, explosive eruptions and effusive eruptions. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra. Effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption.Volcanic eruptions vary widely in strength. On the one extreme there are effusive Hawaiian eruptions, which are characterized by lava fountains and fluid lava flows, which are typically not very dangerous. On the other extreme, Plinian eruptions are large, violent, and highly dangerous explosive events. Volcanoes are not bound to one eruptive style, and frequently display many different types, both passive and explosive, even in the span of a single eruptive cycle. Volcanoes do not always erupt vertically from a single crater near their peak, either. Some volcanoes exhibit lateral and Fissure eruptions. Notably, many Hawaiian eruptions start from rift zones. Scientists believed that pulses of magma mixed together in the magma chamber before climbing upward—a process estimated to take several thousands of years. However, Columbia University volcanologists found that the eruption of Costa Ricas Irazú Volcano in 1963 was likely triggered by magma that took a nonstop route from the mantle over just a few months.