Craig Miller

New earthquake swarm at Whakaari/White Island

Published: Thu Jun 20 2019 2:20 PM
Volcanic Activity Bulletin
Volcanic Activity BulletinWI – 2019/04
Thu Jun 20 2019 2:20 PM; Whakaari/White Island Volcano
Volcanic Alert Level remains at 1
Aviation Colour Code remains at Green

Another earthquake swarm started near Whakaari/White Island at around 4 am Thursday morning, 20 June 2019.

The three largest events are magnitude 4.2, 4.0, 3.7 and were felt at Whakatane. So far, we have located over 95 earthquakes. The location of these earthquakes is the same as the May swarm, that we reported in previous Volcanic Alert Bulletins here and here.

Our analysis of this new swarm confirms its similarity to the May sequence, which was interpreted as fault movement. We are treating today’s swarm as a reactivation of the May swarm. Based on the May swarm we expect this morning’s activity to continue for a few days.

There have been no changes in recorded parameters, and no unusual volcanic activity has been observed at Whakaari/White Island since the May swarm. No unusual volcanic activity has been detected this morning. The National Geohazards Monitoring Centre is keeping a close eye on the earthquakes and for any signs of volcanic unrest.

As with the May swarm there is a heightened likelihood of landslides occurring on the island as the earthquakes are shallow, local, and volcanic rock is relatively weak. Landslides are also more likely during prolonged periods of heavy rain. No landslides have been observed at Whakaari/White Island since the May swarm.

There are no changes in volcano monitoring parameters or the level of volcanic activity at Whakaari/White Island. Our observations are consistent with minor volcanic unrest and the Volcanic Alert Level remains at 1 while the Aviation Colour Code stays at Green.

While Volcano Alert Level 1 is mostly associated with environmental hazards such as volcanic gas, eruptions can still occur with little or no warning. GNS Science continues to closely monitor Whakaari/White Island and our other active volcanoes.

Craig Miller

Duty Volcanologist

Media Contact: Volcanologist Brad Scott (07 3748211)