Residents in the area beneath the volcano were warned to leave; some took valuable possessions with them. The volcano expelled a large quantity of lava which flowed towards a nearby village. About 20 homes were destroyed. Scientific researchers have been monitoring the volcanic gases emitted by the lava.
Through the afternoon explosive activity increased and strong explosions gave rise to discontinuous projections of spatter that reached 50 m high. Streams of gases flowed down the SW slope of the scoria cone and reached the caldera wall on 18 May.
People in the caldera felt nose and throat irritations more than 2 km from the main vents, making it impossible to approach without a gas mask. A strong sulfur smell was reported as far as Patim village, 8 km SW. On this day atmospheric samples were collected near the scoria cone. Boca de Fonte population 56 was completely destroyed, and flow-fronts were m from Portela as of 18 May. During this eruption nobody was killed, but several needed medical assistance, mainly for respiratory problems due to inhalation of volcanic gas and dust.
Gaspar , T. Ferreira , R. Coutinho , and G. Eruption of 2 April through 28 May covered over 6 square kilometers of land. Based on six major-element XRF analyses, the lava flow erupted during the first night 3 April was determined to be a differentiated kaersutite-bearing phonotephrite IUGS system , whereas later lava flows and spatter were more primitive tephrite basanite. Fogo Island consists of a single massive volcano with an 8-km-wide caldera breached to the E. The central cone was apparently almost continuously active from the time of Portuguese settlement in A.
The June-August eruption from caldera vents S and NW of the central cone began with ejection of pyroclastic material. Information Contacts: Richard Moore , U. This Bulletin report covers from June through February The interval's major volcanic event began on 23 November with the eruption of lavas. There was limited information for the multi-year interval between that eruption and the one in This report also contains a list of References at the end for cited sources.
A pre-eruption satellite image figure 5 labels villages within Fogo's summit caldera Cha caldera. The intracaldera cone Pico Pico do Fogo is also the highest point on the island. Lavas overrode both these villages during the eruption and buried the main N-S road across the caldera. Later maps and images show various aspects of the intra-caldera lavas. For further information regarding Fogo's setting, the Copernicus website presents InSar satellite radar-ranging data and E-flank topography of high relevance had lavas escaped this part of the caldera which did not occur in Overview on the eruption.
The 23 November eruption started at local time LT. In years prior to the eruption, the CO 2 fluxes remained low and fairly stable. Residents felt earthquakes the night before the eruption. Lava streamed from a fissure in the caldera on Pico's outer WSW flank. The initial fissure vent emerged in a location near to the vent of the eruption, though materials apparently began to vent at multiple points along the fissure.
Most of the available photos showed strombolian and perhaps vulcanian activity that fed lava flows figures 6 and 7 , but news reports also indicated explosions, lava fountains, and ash emissions. An ash plume from the eruption was visible 90 km W, at the capital, Praia, on the neighboring island of Santiago Farge, Orders were issued to evacuate the villages of Portela and Bangaeira Caesar, , and to evacuate the Parque Natural de Fogo, a large park covering much of the central part of the island Fogo News.
Lower altitude clouds contained ash. An overview of the lava flow dispersal from the eruption is presented below, as a map with emplacement dates depicting the advancing flows figure 8.
The map was created on 25 December , comparatively late in the eruption. The original map has been cropped to emphasize the lava flows, thus leaving Pico outside the area of view.
At the scale of this map the summit would reside at the apex of the curving contours located along map's E margin a spot off the map to the right and in the midst of the words "09 Dec. The late stage advances seen in figure 8 darkest red colors roughly tripled the length of the W-trending lobe.
That web page, and one called Culture Volcan presented an annotated still photo figure 9 that highlighted the three lobes and the eruptive source. Culture Volcan noted damaged to farms and other infrastructure in that area. A photo not shown here showed an impressive pahoehoe lava flow that appeared to be crossing one of the farms. An OVCV report noted that the eruption ended 8 February a total of 77 days ; and some ash columns approached 6 km in altitude.
They estimated some lava flows grew as thick as m. Silva and others discussed the eruption chronology and presented the most complete though still preliminary picture of lava flow advance rates. The eruption vented on the E flank of the " Pico Novo vent with the appearance of four eruptive vents" discharging gases, pyroclastic rocks, and lava.
The N-directed lobe of lava associated with the destruction of Portela village included both aa and pahoehoe types. At the vent, an initial hawaiian stage of fissure eruptions gave way to a later strombolian stage. The vent's main crater grew by the coalescence of small craters; three small vents released aa lava flows. One or two lava tubes developed.
The site emitted loud explosions and strong rumbling. It advanced at an average speed of 0. The flow here buried vineyards, other crops, and houses. Uni-CV Universidade de Cabo Verde also reported that during December, a gas-and-ash plume extended to m above the cone drifting N and tephra was ejected m above the vent's cone.
Uni-CV noted that the temperatures of the lava fronts gradually decreased. According to Uni-CV , during January , dense plumes rose to , m above the cone and tephra rose m above the vent. During January, explosions were followed by noises or bangs. On 12 January , continuous explosions began at , growing stronger, followed by eruptive pulses.
A dense, dark plume rose 2 km in height and drifted E. On 3 February OVCV scientists saw a bluish white discoloration of the air in the caldera, which they judged as the presence of ash. Explosions were heard 1 to 4 times per minute. The ash plume rose to 0. Rock and spatter discharged. Beginning at on 6 February scientists heard explosions at a rate of 2 to 3 per minute.
The observers saw eruptive columns of brownish color that consisted of gases, tephra, and spatter that rose to m in height above the vent. During to , explosions intensified, sending out larger pyroclasts, and eruptive columns achieved heights above the crater of 1. The clouds blew NE and formed dense ash clouds. Around there occurred intervals of lowered intensity lasting a few minutes.
A more energetic episode took place at on the 6th. The 9 March report on the Uni-CV website contained numerous photos and thermal infrared images from fieldwork during early to middle February A satellite view highlights the vent area and its location perhaps ten's of meters E of the vent. Both the and vents trended NE. Other field photos revealed elongate cones constructed around the fissure vents. The inner rims of those vent-engulfing cones were encrusted with sulfur.
SO 2 emissions were almost undetectable on 8 February and continued to remain so at least through 11 February. During that period, the lava front had not moved, and only minor fumarolic activity was present at the edge of the new crater. Lava flow temperatures had dropped. News, human impacts, and photos revealing diverse lava flow morphology. According to Fogo News, by 25 November the lava flow, which was more than 4 km in length, had destroyed much of Portella, Bangaeira and the park headquarters.
Furthermore, the local Fogo island airport closed. Lava destroyed utility poles, hindering communications. Fogo News added that the Cape Verde government responded to the situation by creating a crisis cabinet. On 30 November, the eruption, although quieter for a few days, resumed at dawn, according to Agencia Lusa Lava also closed the only alternative route between the Parque Natural de Fogo and the village of Portela.
A Fogo News story noted that by 2 December, the lava flow passing through Portela had destroyed the primary school, the Pedra Brabo hotel, and several additional houses. Furthermore, ashfall over pastures affected local livestock, especially goats. Ash emissions caused the cancellation of some flights from the island. The news also mentioned that on 6 December the lava flow rate had increased. Based on a Fogo News article, Fogo volcanism decreased on 9 December.
Gas and ash emissions also decreased and were mostly absent by 14 December. Even though the fissure vent's output was apparently low, the remaining buildings in the town of Bangaeira were overtaken by lava. As a result, the government flew in bottles of potable water. The lava flow morphology as well as the societal impact is revealed below through a tiny sampling of available photos. The BBC , and many news outlets prepared galleries on the Fogo eruption.
Martin Rietze and Richard Roscoe documented portions of the eruption. Chrys Chrystello uploaded two videos to Youtube. The first one, posted on 24 November , depicts plumes released from fissures and people evacuating their homes. The second one, posted on 26 November, showed evacuation, the movement of the lava flow across the caldera, and activity at night.
Figure 10 shows three press photos posted online on 2 December. According to the captions, Portela village residents sat in the foreground, meaning that they watched as the lava flow advanced over their community.
They also tried to salvage materials from the destroyed infrastructure. Judging from the photos in figure 10, the thicker areas of lava stood higher than single story buildings. In these photos the encroaching lava front and the flow tops both appear strongly fragmental in nature, composed of blocks of diverse sizes.
In the various photos of figure 10, the molten component of the lava flow, is not clearly apparent on the flow's exposed surface or sprouting out of the fragmental flow. Figure 11, by contrast, depicts a compact lava flow that is clearly composed of a comparatively thin body that came right through the wall and large door in this building.
The flow surface, in this case, is nearly devoid of fragmental material and the comparatively smooth upper surfaces contrast with those in the lava flows seen in figure The article also noted a lack of injuries or deaths from the eruption, despite the obvious catastrophic destruction. Although, there were no fatalities, 1, people were displaced by the eruption. Map Action , a UK-based charity, issued a map of the Fogo refugee situation figure They said that, by 11 December, the lava had covered a few square kilometers and that there were three Internally Displaced Person IDP shelters existing in areas well outside the caldera.
In an assessment report that was released on 16 December , Relief Web said that: "A volcan[ic] eruption [on] Fogo Island, in Cabo [Cape] Verde, began on 23 November and continues as of 16 December The affected people are a predominantly rural community, whose subsistence largely depends on agriculture and livestock. During March online news sources showed residents in the process of road construction and building excavation.
Technical data. The average daily value of carbon dioxide fluxes at Fogo from 23 November through was compiled by four groups figure The fluxes steadily increased during the interval. According to OVCV, the increase in CO 2 suggested that pressure in Fogo's volcanic hydrothermal system had escalated, and that an eruption would soon occur.
Bulletin editors found few if any additional radon measurements leading up to the eruption. For more details on pre-eruption gas emissions, see Dionis and others According to a report by Uni-CV discussing the February interval, their data on sulfur dioxide SO 2 monitoring were provided for civil protection, to help improve crisis management.
That said, we provide a brief summary and cite a few broad comments. SO 2 fluxes emerging from the vent dropped to near zero during February, one factor in determining the end of the eruption the 8th.
Those low fluxes were measured by vehicle-mounted mini-DOAS insturments. From 28 November the team, with interagency support, conducted measurements. One or more field trips to the vent area described conditions there during early and middle February.
Shortly after that the fluxes rose somewhat to several hundred tons per day. After 7 February , temperatures in the vent area of both the fumaroles and at the base of the cone had decreased significantly table 1.
The temperature difference at the two distances are a well known effect associated with absorption of infrared energy as it passes through the atmosphere. Table 1. The temperatures of the cone base and the fumaroles from 7 to 9 February Courtesy of Uni-CV On 23 November , the number of hotspots increased dramatically. Hotspots were recorded daily, and many had a large number of pixels for example, 19 pixels from the Aqua satellite on 25 November By the end of December , the number of hotspots declined.
During January , hotspots were recorded on a total of 11 days. Only one hotspot was observed in February 7 February , and none in March. In addition to the north flow that affected the villages, the eruption also produced flows that moved south and west. The last time Fogo erupted was At the time, lava came within a few kilometers of Portelo, but did not cause serious damage. Prior to that, Fogo erupted in , , and several times in the s.
For ground photography of the eruption, view this gallery from Martin Rietze. Caption by Adam Voiland. Park Passes. Technical Announcements. Employees in the News. Emergency Management. Survey Manual. Fogo, the youngest and most active volcano in the Cape Verde Islands, lies at the western end of a short chain of volcanic islands off the west coast of Africa.
These islands were formed as the African Plate moved eastward over a hot spot, in much the same way that the Hawaiian—Emperor chain formed as the Pacific Plate moves west-northwestward over the Hawaiian hot spot. Fogo Volcano, as viewed from space, on November 24, , at UTC, shows lava flows bright yellow and orange erupting from Pico de Fogo. The island of Fogo itself is a nearly round, single volcano, roughly 25 km 15 mi in diameter. Its summit caldera, Cha das Caldeiras, extends 10 km 6 mi north-to-south, and 7 km 4 mi east-to-west.
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