As the Taal volcano in the Philippines continues to display volcanic activity, scientists from the US identified the distinct symptoms of an impending violent eruption. According to scientists, these signs indicate if a volcano is about to erupt.

The Taal volcano, which is just 50 kilometres from the Philippines' capital Manila, had an initial eruption on January 12, spewing ashes over the surrounding regions. Although the volcano has been relatively quiet since Sunday, irregular seismic movement and volcanic activity has been in the areas near the volcano. Because of these, many people in the Philippines believe the volcano is revving up for a powerful eruption.

Measuring Ground Expansion

Taal Volcano
Twitter grab

According to Michael Manga, a volcanologist from the University of California, Berkeley, volcanoes often show distinct symptoms of an impending eruption, Scientific American reported. Manga said these signs can be used to predict intense volcanic activity. One of these signs is the expansion of the ground near the volcano, which can be measured using GPS instruments. If an expansion is occurring, this means that underground gases, magma or other materials are already moving toward the surface.

This indicates that the volcanic activity will continue and could intensify into a full eruption. Volcanologist Tracy Gregg of the University of Buffalo noted that as magma makes its way to the surface, its movement against the rocks could cause earthquakes. If these seismic activities are getting closer to the surface, this means magma is also doing the same.

Detecting Harmonic Tremors

Taal Volcano, Philippines
Taal Volcano, Philippines Wikimedia Commons

Another sign that volcanologists are looking out for is harmonic tremors. According to Gregg, these occur when the magma flows through rocks at a certain speed. If the pathway of the magma has a distinct shape, the flow could produce a note, which is similar to how air moves through a person's throat when he or she is singing.

This note, or harmonic tremor, indicates that the magma has already made an established route through the rocks. In most cases, detecting harmonic tremors means a volcano is already preparing to erupt.

Currently, agencies in the Philippines are still monitoring the activities of Taal volcano. In preparation for a violent eruption, tens of thousands of residents from the areas surrounding the volcano have already been evacuated. Various reports indicated that a powerful eruption could result in mudflows and even a volcanic tsunami from the lake surrounding the volcano.