Volcanoes are significant geological phenomena that have intrigued scientists for centuries. The recent focus of their attention has been the Whakaari and Ruapehu volcanoes in New Zealand due to new research revealing pre-eruption warning signals. This article delves into the intricacies of these volcanoes and the innovative research conducted using machine learning to understand their behavior.
The New Research on Volcano Behavior
Every volcano is unique, boasting diverse structures like crater lakes or being completely dry, varied magma compositions, and differing elevations. However, underlying commonalities exist in their eruption processes. The new study utilized machine learning to analyze 40 years of seismic data from New Zealand’s volcanoes and three others globally. The researchers were specifically listening for frequencies that could track the movement or build-up of gas, magma, or water at different depths.
The research consistently identified a pattern in the days leading up to all known eruptions of the Whakaari and most Ruapehu and Tongariro eruptions over the past decade. This pattern is the gradual strengthening of a metric referred to as the Displacement Seismic Amplitude Ratio (DSAR), which peaks a few days before each event.
Understanding DSAR
DSAR is a ratio that compares the activity levels of fluids like gas, hot water, or steam at the volcano’s surface to those several hundred meters deep. An increase in DSAR indicates that while surface fluids are calm, the deeper ones are actively moving and vigorously circulating underground. Seismic waves, which are energy waves triggered by earthquakes or explosions recorded on seismographs, play a crucial role in this process.
About Whakaari and Ruapehu
Whakaari, also known as White Island, sits in the Bay of Plenty, 43 miles west of Cape Runaway, eastern North Island, New Zealand. It is an active volcano and forms the top of a submarine vent at the northern end of the Taupo-Rotorua Volcanic Zone. Its peak is Mount Gisborne, rising to 1,053 feet, with scrub vegetation covering the majority of the island’s approximated 1,000 acres land area.
On the other hand, Mount Ruapehu, located in New Zealand’s central North Island, stands tall at 2800m. It comprises a warm crater lake (Te Wai a Moe) and a hydrothermal system concealed by its peak. The volcano is forested below its line of permanent snow cover, while glaciers flow from the peak.
What is a Volcano?
A volcano is an opening on the surface of a planet or moon that allows warmer material to escape from its interior. This escape of material triggers an eruption, which can either be explosive, projecting material high into the sky, or gentler, causing a steady flow of material.
On Earth, the erupted material can range from liquid rock known as lava on the surface and magma underground, ash, cinders, and/or gas. There are three primary reasons why magma might rise and cause eruptions on Earth’s surface. These include tectonic plate movement creating space for magma to rise, tectonic plate convergence causing the crust to melt and form magma, or the warming of magma over hot spots leading to its ascent.
UPSC Civil Services Examination, Previous Year Questions (PYQs)
An example of a previous year question from the UPSC Civil Services Examination involves the Barren Island volcano, which is an active volcano located in Indian territory. It sheds light on the accuracy of statements about the volcano’s location and its last eruption date.
Barren Island is India’s only active volcano and is situated in the Andaman and Nicobar Islands. It is located approximately 140 km from Port Blair, southern parts of the Andaman Island in the Andaman Sea. Its first recorded eruption dates back to 1787, with five reported eruptions in the past century, then a period of silence for the following 100 years. It erupted massively again in 1991. Since then, the volcano has erupted every two-three years, with the latest eruption recorded in February 2016.