Report on Ubinas (Peru) — June 2008
Bulletin of the Global Volcanism Network, vol. 33, no. 6 (June 2008)
Managing Editor: Richard Wunderman.
Ubinas (Peru) Frequent ash plumes pose risk to aviation and residents
Please cite this report as:
Global Volcanism Program, 2008. Report on Ubinas (Peru) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 33:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200806-354020.
16.355°S, 70.903°W; summit elev. 5672 m
All times are local (unless otherwise noted)
Our most recent report on Ubinas (BGVN 33:01) discussed ongoing eruptions with continuous emissions of volcanic ash, rock, and gases during 2006-2007. During that previously discussed interval, ash plumes sometimes reached ~ 9 km altitudes at times, posing a hazard to aviation, ashfall was heavy. The current report discusses activity from the end of the previous report (17 December 2007) through 15 July 2008. During this period, ash plumes were frequent, as indicated in table 4. No thermal alerts have been detected by the University of Hawaii's Institute of Geophysics and Planetology (HIGP) MODIS satellite-based thermal alert system since 27 December 2006.
|Date||Plume altitude (km)||Plume direction|
|19-25 Dec 2007||5.5-7||NE, SW|
|23 Feb 2008||5.5-8.5||SE|
|02 Mar 2008||5.5-6.1||SE|
|09 Mar 2008||7||W, SW|
|17 Mar 2008||5.5-6.1||N|
|26 Mar 2008||3.7-6.7||SW|
|01 Apr 2008||3.7-6.7||NW|
|06 Apr 2008||5.5-6.7||E|
|15 Apr 2008||5.5-7||ENE|
|19-22 Apr 2008||5.5-7.6||ESE, NE|
|23 Apr 2008||5.5-9.1||SE, S|
|30 Apr-03 May 2008||5.5-9.1||NE, E, SE|
|09 May 2008||5.5-7||E|
|12 May 2008||5.5-7||SE|
|15 May 2008||5.5||E, SW|
|19 May 2008||8.5||E, SW|
|22-24 May 2008||4.9-7.9||S, E, NE, SE|
|26 May 2008||5.4||SSE|
|28-29 May 2008||5.5-6.1||NE, SE|
|03 Jun 2008||4.6||SSW|
|07 Jun 2008||7.3||S|
|13 Jun 2008||6.7||S|
|18 Jun 2008||5.5-5.8||S, SE, and NE|
|22 Jun 2008||5.5-7.6||S, SE, NE|
|26 Jun 2008||5.5-6.1||NE|
|07 Jul 2008||5.5-5.8||NE|
|09-10 Jul 2008||5.5-5.8||E|
|15 Jul 2008||5.5-5.8||E|
According to the ash advisories issued from the Buenos Aires VAAC, the aviation warning color code for Ubinas during the reporting period was variously orange or red. In terms of hazard status on the ground, a news article on 30 June 2008 indicated that local civil defense officials had maintained the Alert level at Yellow. They noted that small explosions and ash-and-gas emissions had continued during the previous two months. Families at immediate risk from the village of San Pedro de Querapi in the vicinity of the volcano have been relocated but have returned to their fields to pursue their agacultural activities. The population of local communities and their livestock had suffered the effects of gas and ash emissions, and local authorities had begun to discuss the possible relocation of about 650 affected families from six towns (Escacha, Tonoaya, San Migues, San Pedro de Querapi, Huataga and Ubinas). The article noted that officials recognized that the relocation process could take several years and should be the villager's decision and not one forced on them.
Geologic Background. A small, 1.4-km-wide 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 behind the main volcanic front of Perú. The growth and destruction of Ubinas I was followed by 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 summit caldera contains an ash cone with a 500-m-wide funnel-shaped vent that is 200 m deep. Debris-avalanche deposits from the collapse of the SE flank about 3700 years ago extend 10 km from the volcano. Widespread plinian pumice-fall deposits include one of Holocene age about 1000 years ago. Holocene lava flows are visible on the flanks, but historical activity, documented since the 16th century, has consisted of intermittent minor-to-moderate explosive eruptions.
Information Contacts: Instituto Geológical Minero y Metalúrgico (INGEMMET), Av. Canadá 1470, San Borja, Lima 41, Perú (URL: http://www.ingemmet.gob.pe/); Buenos Aires Volcanic Ash Advisory Center (VAAC), Argentina (URL: http://www.smn.gov.ar/vaac/buenosaires/productos.php); La República Online (URL: http://www.larepublica.com.pe).