Mt Ruapehu Remains Stable Amid Recent Earthquake Activity, Experts Say

Despite a recent swarm of earthquakes near Mt Ruapehu, volcanologists have confirmed that the mountain remains stable, with no significant changes observed. The alert level for the volcano remains at 1, indicating minor volcanic unrest, but experts say there is no immediate cause for concern.

On July 8, more than 90 small and deep earthquakes were recorded beneath the north-eastern flank of Mt Ruapehu. These quakes occurred at intervals of about six to seven minutes. GNS Science, the country's geological monitoring agency, stated that the activity was within the normal range for the region.

Geoff Kilgour, a duty volcanologist, emphasized that no significant changes to the volcano had been observed following the earthquake swarm. He noted that the temperature of Te Wai ā-moe, also known as Ruapehu Crater Lake, remained stable at around 12°C. This is slightly lower than the 17°C recorded in May, but Kilgour said the temperature fluctuation was expected and not unusual.

During a visit on June 8, scientists observed sulphur slicks on the lake surface, which are often associated with hot fluids entering the lake floor. The lake was also seen overflowing, indicating that hydrothermal fluids are still flowing into the crater.

Sulphur dioxide emissions from the volcano remained at a low, continuous level. Kilgour said that while the recent earthquake activity was notable, it did not signal any major changes in the volcano's behavior. He added that the current activity is consistent with the volcano's typical background activity.

Yannik Behr, another GNS Science volcanologist, explained that earthquake swarms are not uncommon in the central North Island, where volcanic fluids interact with existing faults. He suggested that the current sequence of earthquakes might be linked to fluid movement deep beneath the surface. However, no signs of an imminent eruption have been detected.

Although the last eruption of Mt Ruapehu occurred in 2007, the volcano is still considered active. In 1996, a significant eruption sent large clouds of smoke and ash into the air, causing widespread damage and disruptions. Despite its history, experts say the volcano is still in a state of minor unrest and has the potential to erupt with little or no warning.

Scientists will continue to monitor the volcano closely, conducting gas flights and sampling crater lake fluids when weather conditions permit. For now, the community remains on high alert, but no immediate action is required.