the last time a volcano erupted in utah was mount st. helens.
the last time a volcano erupted in utah was mount st. helens.
when was the last time a volcano erupted in utah?
mount st. helens
compared to other types of volcanoes, the tequila volcano lived much longer and was more active since it is a stratovolcano. there is no particular date of when exactly the volcano itself was active, but we can tell whether it was active or not according to its volcanic field and structure. the tequila volcano’s volcanic field is 1600 km^3, showing that it was active at one point in time, it is, however; no longer active. although the volcano is now dormant, if it were to erupt, the explosion would be extremely violent. just like mount fuji and st. helens, stratovolcanoes tend to be very big because they have a conduit system inside them that channels magma from deep within the earth to the surface. these type of volcanoes also have clusters of vents, with lava breaking through walls, or issuing from fissures on the sides of the mountain which allows them to grow big & very tall. stratovolcanoes make up some of the world’s most memorable mountains as well as most violent eruptions, for example, on may 18, 1980, mount st. helens erupted. the eruption covered approximately 230 square miles of a forest that was destroyed and the ash that was in the atmosphere drifted over 11 states with a total number of 57 casualties, however; when the tequila volcano erupted, there were no casualties.
tequila volcano
these geomorphological structures have resulted from millions of years of compound growth that began in the eastern portion of the island; around 4 million years ago the nordeste volcano burst from the ocean floor in effusive and fissural eruptions. these eruptions were composed of basaltic lava flows and spatter cones whose products reached a height of forming the mountainous region of tronqueiro, planalto dos graminhais, espigão dos bois and pico verde (finding its maximum extent in pico da vara). but, about 950,000 years ago a secondary volcano system (volcanic complex of povoação) supplanted the eruptions of the nordeste volcano, responsible for new basaltic lavas and pyroclastic deposits. with an age of 200,000 years the third volcano on são miguel, the água de pau volcano started erupting on the western flank of povoação volcano in two phases. the first phase, composed of the older materials, erupted from lava flows and trachyte pyroclasts, the secondary phase corresponded to volcanic products that began erupting 400,000 years ago. these latter deposits included pyroclastic, trachyte flows (lava and surges), mud flows and a mixture of basalts. in what would become the western portion of the island a fourth volcano formed: the sete cidades volcano erupted 200,000 years ago and continued to erupt until about 36,000 years ago. between 100,000 and 3,800 years ago fissural eruptions of integrated lava and basaltic pyroclastic deposits occurred in the center of the island between água de pau and povoação, forming the fissural volcanic system of congro. these eruptions were explosive and fed by activities in the neighboring volcanic systems. at about 100,000 years a secondary system developed along the frontier of the povoação volcano, the "furnas volcano" complex (the youngest volcanic system) in three phases mixing pyroclastic surges, trachytes, and lava flows, as well as explosive materials. finally, two layers of deposits formed the fissural volcanic system of picos between the volcanic água de pau and sete cidades from 31,000 years ago unifying the island. this formation integrated lavas, basaltic pyroclasts, tuff cones and trachyte domes into two layers (referred to as the ponta delgada and penhal da paz sub-depoists) and compiled to about 5,000 years ago.
são miguel island