IG reported that the eruption at Cotopaxi continued during 1-7 February, characterized by daily emissions of gas, steam, and ash emissions; inclement weather conditions occasionally prevented views. Gas-and-steam emissions were visible rising from the crater on 1 February. Seismicity increased at 0100 on 2 February and was associated with an ash plume that rose 1.3 km above the summit and drifted NW. Later that day emissions containing ash rose as high as 2.5 km and drifted N, NE, and SE. Ashfall was reported in the N part of Parque Nacional Cotopaxi, and in the area of the Tesalia (47 km NNW) and Güitig factories. Ashfall was also reported in the Quito and Mejía regions including in Amaguaña (35 km NNW), Quitumbe (43 km NNW), Conocoto (41 km N), Guamaní, La Ecuatoriana (44 km NNW), Turubamba (43 km NNW), Chillogallo (47 km NNW), La Magdalena, Machachi (24 km NW), Tambillo (32 km NNW), Alóag (28 km NW), and Cutuglahua (35 km NNW). On 3 February ash plumes rose as high as 2.5 km and drifted in multiple directions, and ash fell in Amaguaña, La Armenia, Quitumbe, Conocoto, Guamaní, La Ecuatoriana, Turubamba, Chillogallo, La Magdalena, Machachi, Tambillo, Alóag, Cutuglahua, Uyumbicho (30 km NNW), Aloasí (24 km NW), and El Chaupi (24 km WNW). On 4 February ash plumes rose 1.5 km and drifted NNE and SE. Ashfall was noted in Guamaní, Turubamba, Chillogallo, La Ecuatoriana, Quitumbe, Tambillo, Machachi, Aloasí, Aloag, and Conocoto. On 5 February steam-and-gas emissions with low ash content drifted NW. In the afternoon ash emissions rose 200 m and drifted S. Minor gas emissions were visible during 6-7 February. Servicio Nacional de Gestión de Riesgos y Emergencias (SNGRE) maintained the Alert Level at Yellow (the second lowest level on a four-color scale).

Geological Summary. The symmetrical, glacier-covered, Cotopaxi stratovolcano is Ecuador's most well-known volcano and one of its most active. The steep-sided cone is capped by nested summit craters, the largest of which is about 550 x 800 m in diameter. Deep valleys scoured by lahars radiate from the summit of the andesitic volcano, and large andesitic lava flows extend to its base. The modern edifice has been constructed since a major collapse sometime prior to about 5,000 years ago. Pyroclastic flows (often confused in historical accounts with lava flows) have accompanied many explosive eruptions, and lahars have frequently devastated adjacent valleys. Strong eruptions took place in 1744, 1768, and 1877. Pyroclastic flows descended all sides of the volcano in 1877, and lahars traveled more than 100 km into the Pacific Ocean and western Amazon basin. Smaller eruptions have been frequent since that time.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN)