White Island Resumes Pattern of Minor Activity

Volcanic Alert Bulletin WI-2013/12 - White Island Volcano

26 March 2013, 3:00pm - White Island Resumes Pattern of Minor Activity; Volcanic Alert remains at Level 1, Aviation Colour Code remains Yellow.

GNS Science says that a pattern of repeating minor activity has become established at White Island over the last month. The Volcano Alert Level and Aviation Colour Code remain unchanged at 1 and Yellow, respectively.

Periods of passive steaming and degassing have been accompanied by very low levels of volcanic tremor. This activity has alternated with minor mud and steam explosions from the active crater when there has been strong volcanic tremor. Tremor episodes have lasted from less than one day to over a week.

Recent airborne sulphur dioxide gas measurements on 20 March were at similar levels to over the last month (550 tonnes/day) although carbon dioxide levels were higher (2400 tonnes/day).

The potential for larger, more explosive eruptions that might impact on visitors to the island is always present. Any larger eruptions may occur with no warning to any visitors to the island.

The ultimate outcome of the current activity at White Island remains unclear and GNS Science continues to closely monitor White Island through the GeoNet project.

Background

Unrest at White Island began in July 2012, leading to explosive eruptions and ash emissions in August. A small lava extrusion occurred in November, followed by phreatic, steam driven activity in December which continued through January and February 2013. Very minor ash emissions have been interspersed throughout this eruption sequence as conditions within the craters have changed.

The Volcanic Alert Level ranges from 0 to 5 and defines the current status at a volcano. Level 1 indicates signs of volcanic unrest.

Aviation Colour Codes are based on four colours and are intended for quick reference only in the international civil aviation community.

Steven Sherburn
Duty Volcanologist

ENDS

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