Global Volcanism Program

18 June-24 June 2008

According to news articles, a bulletin issued from Galápagos National Park indicated that eruptive activity from Cerro Azul decreased considerably during 16-17 June and on 18 June incandescent material was no longer ejected.

Sources: EFE News Service

Available Weekly Reports

2008: May | June |

18 June 2008 Back to Top

According to news articles, a bulletin issued from Galápagos National Park indicated that eruptive activity from Cerro Azul decreased considerably during 16-17 June and on 18 June incandescent material was no longer ejected.

Sources: EFE News Service

4 June 2008 Back to Top

Based on field observations, the IG reported on 5 June that the initial eruption on 29 May from the SE flank of Cerro Azul issued from three fissures. Six 'a'a lava flows up to 5 m thick flowed rapidly from a fissure near the caldera; one of the flows reached the next fissure at a lower elevation. A 1-km-long fissure in the central part of the flank emitted multiple lava flows up to 15 m thick. Activity at a third fissure at the lower flank, also about 1 km in length, produced cones and several lava flows.

On 3 June, new thermal anomalies on the SE flank detected in satellite imagery increased in intensity and migrated E in later images. Incandescence in the same area was also noted by ground observers. On 4 June an overflight confirmed the presence of a new vent. A fissure about 400-500 m long emitted lava flows that traveled towards the S coast of Isabela. Blocks were ejected about 60 m above the vents. A VAAC report indicated that an eruption plume drifted 50 km N. On 5 June, thermal anomalies were present on satellite imagery.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG)

28 May 2008 Back to Top

Based on information from the Galápagos National Park, observations of satellite imagery, and seismicity, the IG reported that Cerro Azul started to erupt on 29 May from several points along a radial fissure on the SE flank in the Cinco Cerros area. A thermal anomaly was present on satellite imagery at about the same time incandescence was seen through cloudiness in the direction of the volcano from ground observations. On 30 May, a plume, possibly with low ash content, was seen on satellite imagery drifting NW. An overflight and further observations revealed that lava flows traveled about 10 km down the SE flank over older flows from eruptions in 1978 and 1998. According to a news article, the lava flows were active during 29 May-1 June and burned vegetation on the flanks of the volcano.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG) , Agence France-Presse (AFP)

Summary of eruption dates and Volcanic Explosivity Indices (VEI).

Start Date	Stop Date	Eruption Certainty	VEI	Evidence	Activity Area or Unit
2008 May 29	2008 Jun 17	Confirmed	1	Historical	Summit and SE flank
1998 Sep 15	1998 Oct 21	Confirmed	1	Historical	N & W caldera floor, SE flank (630-680 m)
1979 Jan 29	1979 Mar 4 (in or after)	Confirmed	2	Historical	East flank (300 m) and summit
[ 1968 Jun 12 ]	[ Unknown ]	Uncertain			North flank?
1959 Jun 29	1959 Jul 31 (?)	Confirmed	2	Historical	East flank
1951	Unknown	Confirmed		Historical
1949 (?)	Unknown	Confirmed	0	Historical
1948 Jun 30 ± 30 days	Unknown	Confirmed	0	Historical
1943 Apr 13 ± 2 days	1943 May 11 (?)	Confirmed	3	Historical	Caldera ring fracture
1940	Unknown	Confirmed	0	Historical	East flank (Cerro de Las Animas)
1932	Unknown	Confirmed	1	Historical
1850 (after)	Unknown	Confirmed	1	Surface Exposure
1250 (after)	Unknown	Confirmed	0	Surface Exposure
550 BCE ± 1000 years	Unknown	Confirmed	0	Surface Exposure
950 BCE ± 1000 years	Unknown	Confirmed	0	Surface Exposure

Located at the SW tip of the J-shaped Isabela Island, Cerro Azul contains a steep-walled 4 x 5 km nested summit caldera complex that is one of the smallest diameter, but at 650 m one of the deepest in the Galápagos Islands. The 1640-m-high shield volcano is the second highest of the archipelago. A conspicuous bench occupies the SW and west sides of the caldera, which formed during several episodes of collapse. Youthful lava flows cover much of the caldera floor, which has also contained ephemeral lakes. A prominent tuff cone located at the ENE side of the caldera is evidence of episodic hydrovolcanism at Cerro Azul. Numerous spatter cones dot the western flanks of the volcano. Fresh-looking lava flows, many erupted from circumferential fissures, descend the NE and NW flanks of the volcano. Historical eruptions date back only to 1932, but Cerro Azul has been one of the most active Galápagos volcanoes since that time. Solfataric activity continues within the caldera.