Volcanic Activity
Historical eruptions of the Tungurahua III volcano, have all originated from the summit crater. They have been accompanied by strong explosions and sometimes by pyroclastic flows and lava flows that reached populated areas at the volcano's base. “The Tungurahua volcano III has produced at least 16 eruptions with pyroclastic and lava flows” (Le Pennec et al., 2005). An eruption in 1999 caused the temporary evacuation of the city of Baños, located at the foot of the volcano. The last major eruption occurred from 1916 to 1918, with minor activity continuing until 1925. In addition to the current activity of the volcano, the historical documents reported four eruptive periods after the Spanish conquest: 1640, 1773, 1886 and 1916 - 1918 A.D. “The eruptions were characterized by explosive episodes that generated pyroclastic products” (Le Pennec et al., 2005). The events of 1773 and 1886 ended with the emission of lava flows. |
Associated Danger and impact to the population
Ash fall and pyroclastic, material is ejected from the crater of the volcano. The larger fragments fall near the crater, usually on the upper parts of the volcano, while the ash is carried by the wind and falls at a greater distance, covering large areas near the volcano. The ash affects the health of individuals, since it produces irritation of the eyes and the respiratory tract. Pyroclastic flows, are very hot mixtures of gases, ash and fragments of rocks that descend the flanks of the volcano, moving at speed up to 125 mph (more than 250 km/h). This phenomenon is extremely dangerous, due to the speed at which the pyroclastic flow travels. This type of phenomenon has been extremely frequent in the past, as well as in the recent eruptive phase of the volcano. Mudflows (lahars), are mixtures of volcanic materials (rocks, pumice, and sand), swept away by the water from heavy rains, or melting snow or ice, from the top of the volcano. These flows move downslope at high speed, up to 65 mph. (100 km/h). Due to their high density and velocity, the lahars can move and drag objects of large size and weight, such as bridges, trees, and vehicles, among others. During the present eruptions, countless mudflows have occurred on the western, northwest and southwest flanks. Lava flows, In the case of the Tungurahua volcano, the lava flows consist of molten rock, generated in a crater, or fracture of the flanks of the volcano. The lava flows can travel downslope at low speeds. In spite of destroying everything in its path, the lava flows rarely represent a threat to human life, due to the slowness of their movement. Volcanic gases, are commonly detected before, during and after a volcanic eruption however, in the case of Tungurahua, gas concentrations have not caused negative effects to living beings. |
Volcanic Monitoring
The Tungurahua volcano is monitored by the IG, through different volcanic instrumentation systems. In 1999, the Observatory of the Tungurahua volcano was established that works 24 hours a day, 365 days a year. It is located 9 miles (14 km) from the volcano in the area of Guadalupe, in order to have permanent monitoring that can provide warnings to authorities and the community in case of eruptions. Other organizations help to monitor the activity of this volcano, including the National Secretariat of Risk, the Emergency Operations Committee of the province, and community leaders. Many volunteers and leaders from different groups of communities that live in areas near the volcano also help to monitor the volcano. |