The shockwave generated by the massive volcanic eruption in Tonga in the Pacific Ocean on Saturday, which was felt in many parts of the globe, was recorded in Chennai as well, which is located 12,000 km away.
On Saturday, around 8.15 p.m., it was recorded as a blip in the atmospheric pressure that suddenly spiked by around two hectopascals (hPa) in Chennai, around 10 hours after the eruption happened in Tonga.
The official pointed out that, as the temperature altered in the sea, there might be changes in the rainfall prediction in the future. “As the volcano erupted at a height of at least 20 km when it erupted a pressure occurred in the atmosphere which created a shock wave in the Pacific Ocean across the country. All barometers captured the shock wave for a few minutes caused by the Tonga volcano eruption. Even the barometer in Chennai recorded the shock wave around 8.15 pm at Meenambakkam on Saturday,” said N Puviarasan, Director, Area Cyclone Warning Centre, Regional Meteorological Center (RMC).
The eruption of the submarine volcano took place at 5.15 p.m. local time on Saturday (10.15 a.m. IST), triggering tsunami waves of varying intensity along the coasts of many countries on the Pacific Ocean. Detailed information about its impact on Tonga is yet to emerge as communication remains cut off.
The sound was heard in some places in New Zealand, located roughly 2,500 km away. The Alaska Volcano Observatory in the United States, reported that a part of the shockwave measured there was in the audible range. The observatory tweeted one of their scientists saying, “The very large signal is not that surprising considering the scale of the eruption, but the audible aspect is fairly unique.”
While it could not be heard in India, it was recorded as a sharp but minor increase in atmospheric pressure.
S. Venkataramanan, a Ph.D scholar from IIT Madras, who has a small weather station installed in his house in West Mambalam, was in the middle of some work when he accidentally noticed that his barometer recordings showed a sudden increase in the atmospheric pressure from 1,012.5 hPa to 1,014.53 hPa around 8.15 p.m. “It looked bizarre. I initially wondered if it was a problem with my equipment. A sudden spike and drop were unusual,” he said.
He then immediately reached out to the active weather blogging community in Chennai, who corroborated his readings. “I contacted some from Bengaluru as well, who also recorded the spike. There was a delay of around 20 minutes, which the shockwave took to reach the skies of Bengaluru from Chennai. Only then was it confirmed that it was the effect of the shockwave from the Tonga eruption,” he added.
N. Puviarasan, Director, Area Cyclone Warning Centre, Regional Meteorological Centre, Chennai, said he was alerted on Sunday by his staff who had noticed the blip around the same time. “We were initially surprised as well. Huge winds brought from nearby regions can at times cause the atmospheric pressure to suddenly rise. However, the spike on Saturday looked very different,” he mentioned.
He also concluded that it was the shockwave from Tonga after pulling out reports from different weather stations across the country, all of which showed the spike, albeit with slight differences in time. Mr. Venkataramanan said the rare event was yet another reminder that nature had no boundaries.
