Savo volcano monitoring intensifies amid signs of awakening, Solomon Islands

The Geology Survey Division (GSD) of the Ministry of Mines and Energy has heightened its monitoring of the Savo volcano in Central Province, following recent signs of abnormal seismic activity. While officials urge the public not to panic, they advise staying informed about further developments and following safety information and warnings.

• The last eruption of this volcano took place in 1847 (VEI3).
• Spanish explorers arrived in 1568 during the first historical eruption of Savo. Pyroclastic flows during the climactic phase killed almost all inhabitants of the island, and oral traditions also note the expansion of the island on the northern side.

GSD has been monitoring the seismic activity at the Savo volcano in Central Province since last week. According to a public statement released by the Division, the volcano is displaying abnormal patterns, indicating that it might be waking up.¹

Despite the unusual activity, the GSD has urged the public, particularly those residing in Savo, not to panic. They should instead stay informed about further developments and follow the provided safety information and warnings. The Division is responsible for monitoring earthquakes and volcanoes in the country and will release additional information as required.

On July 28, 2022, residents on Savo in the Solomon Islands reported increased seismicity to the authorities. A GSD team and the National Disaster Management Office (NDMO) investigated the volcano two days later. They observed steam-and-gas emissions rising from an area in the crater, which might indicate an active fissure. On July 31, the GSD briefed the National Disaster Operations Committee and other authorities about the increased seismicity, leading to a preparedness response. Response actions included ongoing monitoring of the island, deployment of technical teams, and the issuance of Volcano Safety Messages to inform residents on the island and surrounding areas.²

Carlos Tatapu, Geo-Hazard Officer at the Seismological Service Division, stated that the government had been closely monitoring the volcanic activity on Savo in recent years.

In the past, the Solomon Islands have experienced the eruption of the Tinakula Volcano in Temotu province, which is one of the country’s most active volcanoes. Since last year, the government has been collaborating with the U.S. Geological Survey’s Volcanic Disaster Assistance Program (VDAP) to install monitoring equipment and train local officers on Savo Island.

The equipment has been set up in Visale, North West Guadalcanal, and Savo Island, Central Islands Province. This collaboration allows the Seismological Service Section to monitor the Savo volcano’s activity during earthquakes or volcanic eruptions.

Geological summary

The 6 x 7 km (3.7 x 4.3 miles) island of Savo consists of a forested andesitic-to-dacitic stratovolcano with a shallow, elliptical 1 x 1.5 km (0.6 x 0.9 miles) wide summit crater.

Lava domes of historical age are located on the crater floor and its NE rim, and older domes occur on the flanks of the volcano.

Pyroclastic flows and mudflows traveled down valleys from the summit crater to form debris fans along the coast.

Thermal areas located in the summit crater, the south to SE flanks, and offshore include areas of steaming ground, fumaroles, small geysers, and hot springs.

Spanish explorers arrived in 1568 during the first historical eruption of Savo. Pyroclastic flows during the climactic phase killed almost all inhabitants of the island, and oral traditions also note the expansion of the island on the northern side.

Other eruptive episodes occurred during the mid-17^th century and during the 1830s to 1840s.³

References:

¹ Savo volcano under watch – Solomon Star – March 20, 2023

² Global Volcanism Program, 2021. Report on Savo (Solomon Islands). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 July-3 August 2021. Smithsonian Institution and US Geological Survey.

³ Savo – Geological summary – GVP

Featured image: Savo Island, Solomon Islands on March 21, 2023. Credit: Copernicus EU/Sentinel-2, The Watchers