Arenal, Costa Rica Reports from 2001: | March | April | Reports from 2003: | January | September | Reports from 2004: | July | Reports from 2005: | November | Reports from 2006: | March | April | May Arenal Eruption History Information from the Si/USGS Global Volcanism Program ------------------------------------------------------------------ 21-27 March 2001 OVSICORI-UNA reported on 26 March that at least three pyroclastic-flow episodes occurred on 24 March between 1234 and 1342. Unlike previous pyroclastic flows, these descended the W flank. National Park guards observed the resulting ash clouds moving SW. There were no reports of injuries or damage. Source: Observatorio Vulcanologico y Sismologico de Costa Rica ------------------------------------------------------------------ 28 March- 3 April 2001 On 29 March OVSICORI-UNA personnel visited the area affected by pyroclastic flows that traveled down the flanks of Arenal on 24, 25, and 26 March. The pyroclastic-flow deposits were located on the N and NE flanks of the volcano. The ash clouds produced from the pyroclastic flows drifted towards the W and SW, depositing ash on an area up to 10 km2 including two towns. Some of the block-and-ash deposits were several meters thick and the debris fan was up to 250 m wide. There were no reports of injuries or damage to buildings. Source: Observatorio Vulcanologico y Sismologico de Costa Rica ------------------------------------------------------------------ 8-14 January 2003 During December activity at Arenal consisted of continuous gas emissions, lava flows towards the W flank, and sporadic Strombolian eruptions. In addition, fumarolic activity occurred at Crater D. Source: Observatorio Vulcanológico y Sismológico de Costa Rica, Universidad Nacional ------------------------------------------------------------------ 3-9 September 2003 A sequence of pyroclastic flows began at Arenal on 5 September at 1055. Seismographs recorded eight signals within 2 hours after the activity began. Lava flows descended to 800 m down the volcano's N and NE flanks. Ash drifted towards the W and NW. No injuries or deaths were reported and the main effects were limited to the National Park boundaries. Sources: Observatorio Vulcanológico y Sismológico de Costa Rica via the Volcano Listserv, Associated Press, Reuters ------------------------------------------------------------------ 7-13 July 2004 Since an eruption during the evening of 6 July sent an avalanche of lava cascading down the side of Arenal volcano, no subsequent activity has been reported. According to news reports, on 7 July, Costa Rica's National Emergency Commission (CNE) issued an alert and prohibited people from approaching the volcano. Source: AFP News ------------------------------------------------------------------ 2-8 November 2005 Explosive activity began at Arenal on 2 November at 1454. A pyroclastic flow was generated at 1502 and movement continued for ~10 minutes. During a visit to the volcano the next day, OVISICORI-UNA scientists found that the mid-sized pyroclastic flow traveled down the volcano's W flank, producing an ash cloud that drifted SE. An area was impacted that extended from the volcano's summit to about 1,000 m a.s.l. on Arenal's W flank. The pyroclastic flow occurred in an area that is closed to visitors. During the previous several months lava flows on the volcano's SW flank had been growing rapidly. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVISICORI-UNA) ------------------------------------------------------------------ 8-14 March 2006 In February, activity at Arenal's Crater C consisted of lava flows traveling SW and W, gas emission, sporadic Strombolian eruptions, and occasional avalanches from lava-flow fronts. Volcanic activity was at low levels, with few eruptions occurring and a small amount of pyroclastic material ejected. Eruptions produced ash plumes that rose ~500 m above the crater (or 7,100 ft a.s.l.). Ash and acid rain fell on the NE, E, and SE flanks. Small avalanches of volcanic material traveled down several ravines. There was only fumarolic activity at Crater D. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) ------------------------------------------------------------------ 29 March-4 April 2006 OVSICORI reported that on 2 April around 1000 a small pyroclastic flow traveled down Arenal's W flank. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVSICORI-UNA) ------------------------------------------------------------------ May 10-16 2006 On 10 May around 1000, a pyroclastic flow traveled down Arenal's N flank. An ash-and-gas cloud was produced that drifted SW. Source: Observatorio Vulcanologico y Sismologico de Costa Rica-Universidad Nacional (OVISICORI-UNA) - "Report provided courtesy of the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program."