New eruptive process at Ubinas volcano, alert level raised to Yellow, Peru

The Ubinas volcano, located in the Moquegua Region of Peru, has entered a new phase of activity. The Ministry of the Environment (MINAM) and the Geophysical Institute of Peru (IGP) reported the first ash emissions from the volcano on June 22, 2023, marking the start of a new eruptive process.

Instituto Geofísico del Perú (IGP) — the official institution for monitoring and warning of volcanic eruptions in Peru — reported that seismicity at Ubinas had been increasing since mid-May, and that from June 1 to 18, fumarolic plumes rose 500 m (1 640 feet) above the crater rim. The Gobierno Regional de Moquegua raised the Alert Level to Yellow (the second lowest level on a four-color scale) on June 20 based on the recommendation from IGP.¹

The IGP has drawn on its experience with previous eruptions over the last 30 years to predict the potential duration and impact of this current activity. The institute suggests that the Ubinas volcano’s activity could extend for several months, similar to the eruptions that occurred in 2006-2009, 2013-2017, and 2019. These eruptions were characterized by the expulsion of volcanic ash, which was dispersed by the winds towards nearby locations.²

Marco Rivera, an IGP scientific researcher in volcanology, noted that the emissions observed in the early morning of June 22 were slight, reaching an approximate height of 1 km (3 280 feet), and were dispersed towards the eastern sector of the volcano. Rivera stated, “We are carefully observing the evolution of the new eruptive process of the volcano. We do not rule out that new ash emissions of greater volume will occur in the following hours or days.”

Hernando Tavera, the executive president of the IGP, emphasized that the authorities of INDECI and the Regional Government of Moquegua and Arequipa have been alerted about this reactivation process. They have been advised to execute their contingency plans against a possible volcanic eruption and a potential increase in activity.

Tavera concluded, “A little over a month ago, the IGP complied in noticing the first signs of unrest in the Ubinas volcano. Today, one of the scenarios that we mentioned to the authorities and the population has taken place. This is clear evidence of a successful new eruption forecast that the IGP achieves. With that same commitment, we will continue to provide information on the evolution of volcanic activity.”

Geological summary

A small, 1.4-km-wide (0.8 miles) caldera cuts the top of Ubinas, Peru’s most active volcano, giving it a truncated appearance. It is the northernmost of three young volcanoes located along a regional structural lineament about 50 km (31 miles) behind the main volcanic front of Perú.

The growth and destruction of Ubinas I was followed by the construction of Ubinas II beginning in the mid-Pleistocene.

The upper slopes of the andesitic-to-rhyolitic Ubinas II stratovolcano are composed primarily of andesitic and trachyandesitic lava flows and steepen to nearly 45 degrees.

The steep-walled, 150-m-deep (492 feet) summit caldera contains an ash cone with a 500-m-wide (1 640 feet) funnel-shaped vent that is 200 m (656 feet) deep.

Debris-avalanche deposits from the collapse of the SE flank about 3 700 years ago extend 10 km (6.2 miles) from the volcano. Widespread Plinian pumice-fall deposits include one of Holocene age about 1 000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16^th century, has consisted of intermittent minor-to-moderate explosive eruptions.³

References:

¹ IGP registra las primeras emisiones de ceniza en el volcán Ubinas – IGP – June 22, 2023

² Smithsonian Institution / US Geological Survey – Weekly Volcanic Activity Report – June 14 – 20, 2023 – Managing Editor: Sally Sennert. Written by Zachary W. Hastings.

³ Ubinas – Geological summary – GVP

Featured image credit: Copernicus EU/Sentinel-2, EO Browser, The Watchers. Acquired on June 23, 2023