PRODUCTS

Portable Fluxmeters

Continuous mon. Fluxmeter

GPS Telemetries

El Salvador, San Salvador, Santa Ana, San Miguel, San Vincente, Berlin, Auachapan.
Managed by:
LaGeo/University of El Salvador/Ministerio Medio Ambiente

Soil carbon dioxide flux continuous monitoring. Carbon dioxide concentration continuous monitoring. Piezometric Water level an temperature.

La Palma
Canary Islands, Spain
28.58°N, 17.83°W; summit elev. 2,426 m

The wedge-shaped island of La Palma contains two large volcanic centers. The northern one is cut by the massive Caldera Taburiente. The southern Cumbre Vieja rift volcano, oriented N-S, has been the site of historical eruptions recorded since the 15th century. An eruption from the S tip of La Palma in 1971 produced the Teneguia cinder cone. Fissure-fed eruptions from vents ~1 km S of the 1677 San Antonio cone produced lava flows that reached the SW coast.

from : www.volcano.si.edu

Masaya Volcano, Nicaragua 11.984°N, 86.161°W; summit elev. 635 m

Masaya is one of Nicaragua's most unusual and most active volcanoes. It is a broad, 6 x 11 km basaltic caldera with steep-sided walls up to 300 m high that is filled on its NW end by more than a dozen vents erupted along a circular, 4-km-wide fracture system. Masaya lies within the massive Pleistocene Las Sierras pyroclastic shield volcano. The twin volcanoes of Nindiri and Masaya, the source of historical eruptions, were constructed at the southern end of the fracture system and contain multiple summit craters. A major basaltic plinian tephra was erupted from Masaya about 6500 years ago. Historical lava flows cover much of the caldera floor and have confined a lake to the far eastern end of the caldera. A lava flow from the 1670 eruption overtopped the N caldera rim. Masaya's active summit crater, Santiago, produced recently an explosion on 23 April. The explosion continued for ~2 minutes and a new 10-m-diameter vent opened on the crater floor ~30 m S of the previous vent. Fragments up to 60 cm in diameter flew through the air, falling up to 500 m from the crater. Episodic ashfall was reported near the settlement of Tecuantepe, 6 km NW of Masaya volcano (Bulletin v. 26, no. 04).

from : www.volcano.si.edu

The realization of this project would not have been possible without the essential contribution of: Carlos Cordero, Carlos Ramirez and all the people of the Parque Nacional volcán Poás.

POAS Costa Rica 10.20°N, 84.233°W; summit elev. 2,708 m

Poás, one of the most active volcanoes of Costa Rica, is a broad, well-vegetated volcano with a summit area containing three craters along a N-S line. The frequently visited multi-hued summit craters of one of Costa Rica's most prominent natural landmarks are accessible by vehicle. The 2708-m-high complex stratovolcano is constructed within eroded remnants of nested 7- and 3-km-wide calderas. A N-S-trending fissure extending to the lower north flank has produced the Congo stratovolcano and several maars. The southernmost of two summit crater lakes, Botos, is cold and clear, and last erupted about 7500 years ago. The other is warm and acid and has been the site of frequent phreatic and phreatomagmatic eruptions since the first historical eruption was reported in 1828. Poás eruptions often include geyser-like ejection of crater lake water.

General References: Casertano, L., Borgia, A., Cigolini, C., Morales, L.D., Montero, W., Gómez, M., and Fernández, J.F., 1985, Investigaciones geofísicas y caracteristicas geoquímicas de las aguas hidrotermales: Volcán Poás, Costa Rica: Geofísica Internacional, v. 24, p. 315-332.

Prosser, J., 1985, Geology and medium-term temporal magmatic variation found at the summit region of Poás volcano, Costa Rica: Boletín de Vulcanología, n. 15, p. 21-39.

from : www.volcano.si.edu

fter the January 2001 earthquake the Spanish Cooperation Agency and the Instituto Tecnológico y de Energías Renovables (Tenerife), have financed the construction of a station network for geochemical monitoring for volcanic hazard mitigation in El Salvador. Four continuous monitoring stations for Carbon Dioxide flux, two of which also able to measure Hydrogen Sulfide flux, were installed on San Salvador, San Miguel, San Vincente e Santa Ana volcanoes. The network is managed by Ministerio del Medio Ambiente and by the Universidad del Salvador.

The realization of this project would not have been possible without the essential contribution of:

• AECI (Spanish Agency for International Cooperation) Coordinator in El Salvador
  Mr. Francisco Sancho
• Spanish Embassor in El Salvador
  Mr. Francisco Montalbán Carrasco
• Ministry of Environment and Natural Resources, Government of El Salvador
  Dr. Ana María Majano
  C.Pullinger, Mario , Ricardo
• N.Perez, J.Salazar, Eleazar : ITER Tenerife Spain.
• University of El Salvador professors:
  Tomás Soriano
  Rafael Cartagena
  Francisco Barahona
  Rodolfo Olmos
• Cobra, Apocalypsis, Delphin, Moses: Grupo de Reaccion Policial (G.R.P.) El Salvador’s Civil National Police
  (Our security while in El Salvador)

San Vincente Infernillo

San Vincente, Infernillo fumarolic field

The G.R.P. of El Salvador

Terceira :: Terceira Island contains four stratovolcanoes constructed along a prominent ESE-WNW-trending fissure zone that cuts across the island. Historically active Santa Barbara volcano at the western end of the island is truncated by two calderas.

San Miguel :: Furnas volcano lies at the eastern end of Sao Miguel Island, immediately west of the older Nordeste shield volcano and its Povoaçao caldera. Furnas contains at least two calderas, a younger one that is 6-km wide and a larger older one that is less topographically distinct.

San Miguel :: Agua de Pau stratovolcano in central Sao Miguel Island contains an outer 4 x 7 km caldera formed about 30,000 to 45,000 years ago and an inner 2.5 x 3 km caldera that was created about 15,000 years ago. The younger caldera is partially filled by the Lagoa do Fogo caldera lake. Several post-caldera lava domes were emplaced on the northern and western flanks of the volcano, but activity in the caldera did not resume until about 5000 years ago. The 3-cu-km Fogo-A plinian pumice-fall deposit, the product of the largest-known Holocene eruption in the Azores, was emplaced at this time. The latest trachytic explosive eruption took place during 1563.

Graciosa :: The SE end of Graciosa, the northernmost of the central Azorean islands, contains a small 0.9 x 1.6 km caldera with active fumaroles. The 402-m-high SE caldera rim is the high point of the small 4 x 8 km island. The caldera has been the source of eruptions producing significant tephra falls, pyroclastic flows, lahars, and lava flows. An important fumarole field is located in a volcanic cave inside the caldera.

from : www.volcano.si.edu

Usu
Hokkaido, Japan
42.53°N, 140.83°E; summit elev. 731 m
All times are local (= UTC + 9 hours)
Usu is a small stratovolcano located astride the southern topographic rim of the 110,000-year-old Toya caldera. The 10-km-wide, lake-filled caldera contains Naka-jima island in its center, a group of forested, andesitic lava domes. At Usu volcano, on the south rim of the caldera, dacitic domes fill and surround the north side of a somma formed about 7-8,000 years ago when a debris avalanche destroyed the summit and reached the sea. Three of these domes, O-Usu, Ko-Usu and Showa-Shinzan, along with seven crypto-domes, were erupted in historical time. The war-time growth of Showa-Shinzan was painstakingly documented by the local postmaster, who created the first detailed record of growth of a lava dome.

from: www.volcano.si.edu

Description of the Gas Disasters in Lakes Nyos and Monoun:
On 26 August 1986 an enormous volume of carbon dioxide (CO2) was released from Lake Nyos that killed about 1700 people. Two years earlier in Lake Monoun there was a smaller release of CO2 that killed 37 people. Two possible explanations for these events were originally proposed, and were centered around a limnologic hypothesis (limnology is the study of lakes and streams) and a volcanic eruption hypothesis. This rare natural disaster is complex, little understood, and difficult to study. Below and in the accompanying articles it is shown that these events were essentially limnological in origin, and that volcanic activity at the time of the events was absent.

Vesuvius
Italy
40.82°N, 14.43°E; summit elev. 1,281 m

The Somma-Vesuvius volcanic complex is a central composite volcano formed by an older stratovolcano (Monte Somma) with a summit caldera partially filled by the composite cone of Vesuvius. The most noted eruption, in 79 A.D., destroyed the ancient cities of Pompeii and Herculaneum. Since the explosive sub-Plinian eruption of 1631, Vesuvius has erupted with both Strombolian and mixed effusive-explosive styles. For the past three centuries the volcanic activity has mainly focused inside the Somma caldera but occasionally lava issued outside it (i.e., 1760 eruption). The last cycle of activity ended with the 1944 eruption. Since then, the volcano has been characterized by moderate seismicity and intra-crater fumarolic activity.

Campi Flegrei
southern Italy
40.827°N, 14.139°E; summit elev. 458 m
Campi Flegrei is a large 13-km-wide caldera on the outskirts of Naples that contains numerous phreatic tuff rings and pyroclastic cones. The caldera margins are poorly defined and on the south lie beneath the Gulf of Pozzuoli. Episodes of dramatic uplift and subsidence within the caldera have occurred since Roman times. The earliest known eruptive products are dated 47,000 years before present (BP). The Campi Flegrei caldera formed following two large explosive eruptions, the massive Campanian ignimbrite about 34,000 years BP, and the Neapolitan Yellow Tuff (NYT) about 12,000 years BP. Following eruption of the NYT a large number of eruptions have taken place from widely scattered subaerial and submarine vents. Most activity occurred during two intervals: 10,500-8000 and 4600-3700 years BP. Two eruptions have occurred in historical time, one in 1158 at Solfatara and the other in 1538 that fomed the Monte Nuovo cinder cone.

from : www.volcano.si.edu

Stromboli
Aeolian Islands, Italy
38.79°N, 15.21°E; summit elev. 926 m

Spectacular incandescent nighttime explosions at Stromboli volcano have long attracted visitors to the "Lighthouse of the Mediterranean." Stromboli, the NE-most of the Aeolian Islands, has lent its name to the frequent mild explosive activity that has characterized its eruptions throughout historical time. The small, 926-m-high island of Stromboli is the emergent summit of a volcano that grew in two main eruptive cycles, the last of which formed the western portion of the island. The active summit vents are located at the head of the Sciara del Fuoco, a horseshoe-shaped scarp formed as a result of slope failure that extends to below sea level and funnels pyroclastic ejecta and lava flows to the NW. Essentially continuous mild strombolian explosions, sometimes accompanied by lava flows, have been recorded at Stromboli since Roman times.

from : www.volcano.si.edu

Etna
Sicily, Italy
37.73°N, 15.00°E; summit elev. 3,315 m

Mount Etna, towering above Catania, Sicily's second largest city, has one of the world's longest documented records of historical volcanism. Historical lava flows cover much of the surface of this massive basaltic stratovolcano, Italy's highest and most voluminous volcano. The Mongibello stratovolcano, truncated by several small calderas, was constructed during the late Pleistocene and Holocene over an older shield volcano. The most prominent morphological feature of Etna is the Valle del Bove, a 5 x 10 km horseshoe-shaped caldera open to the east. Two styles of eruptive activity typically occur at Etna. Persistent explosive eruptions, sometimes with minor lava emissions, take place from one or more of the three prominent summit craters, the Central Crater, NE Crater, and SE Crater (the latter formed in 1978). Flank vents, typically with higher effusion rates, produce eruptions from fissures that open progressively downward from near the summit (usually accompanied by strombolian eruptions at the upper end). Cinder cones are commonly constructed over the vents of lower flank lava flows. Lava flows extend to the foot of the volcano on all sides and have reached the sea over a broad area on the SE flank.

General References: Romano, R., ed., 1982, Mount Etna volcano: A review of recent earth sciences studies: Memorie della Società Geologica Italiana, v. XXIII, 205 p. + maps.

Chester, D.K., Duncan, A.M., Guest, J.E., and Kilburn, C.R.J., 1985, Mount Etna: The Anatomy of a Volcano: Stanford University Press, 404 p.

from : www.volcano.si.edu