What was the VEI of Nevado del Ruiz 1985?
VEI 3
Thirty years ago the volcano of Nevado Del Ruiz became infamous around the world when a VEI 3 eruption on the 13th November 1985 melted its snowcap and generated lahars that hurtled down its slopes, ultimately killing over 24,000 people.
What was the volcanic explosivity index for Nevado del Ruiz?
between 2 and 3
An eruption of moderate volcanic explosivity index (VEI) between 2 and 3, on November 13, 1985, triggered a large lahar that destroyed the city of Armero ~30 km away from the summit, and killed 22,000 people1,2,3. It also affected the populations of Chinchina and Rio Claro causing approximately 3,000 fatalities.
What happened when Nevado del Ruiz erupted in 1985?
On the November 13, 1985, an explosive eruption at the Arenas Crater (image center) melted ice and snow at the summit of the volcano. Mudflows (lahars) swept tens of kilometers down river valleys along the volcano’s flanks, killing at least 23,000 people.
What caused the mudflows 1985 on the Nevado del Ruiz volcano?
The eruption of Nevado del Ruiz in Colombia on 13 November 1985 was accompanied by the formation of four lahars (mud flows) triggered by the melting of glacial ice near the summit of the volcano.
What was the magnitude of the Nevado del Ruiz eruption in 1985?
At 9:09 p.m., on November 13, 1985, Nevado del Ruiz ejected dacitic tephra more than 30 kilometres (20 mi) into the atmosphere. The total mass of the erupted material (including magma) was 35 million metric tons, only three percent of the amount that erupted from Mount St. Helens in 1980.
What does Vei mean in volcanoes?
The Volcanic Explosivity Index (VEI) is a scale that describes the size of explosive volcanic eruptions based on magnitude and intensity. The numerical scale (from 0 to 8) is a logarithmic scale, and is generally analogous to the Richter and other magnitude scales for the size of earthquakes.
How many people died from Mount Ruiz eruption?
An explosive eruption on 13 November melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than [25,000] people. This is history’s fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000) and Mt.
What type of lava does Nevado del Ruiz have?
Nevado del Ruiz covers more 200 sq km and it is composed by 3 major andesitic and dacitic edificed of lavas and tuffs. The present-day cone is composed by lava domes built within the summit caldera of the older Ruiz volcano. Its summit contains the 1-km-wide and 240-m-deep Arenas crater.
How big was the Nevado del Ruiz eruption?
At 3:06 pm, on November 13, 1985, Nevado del Ruiz began to erupt, ejecting dacitic tephra more than 30 kilometres (19 mi) into the atmosphere. The total mass of the erupted material (including magma) was 35 million tonnes—only 3% of the amount that erupted from Mount St. Helens in 1980.
Is a VEI 9 eruption possible?
It is possible that evidence for a VEI 9 eruption exists and is buried in the geologic record. Eruptions that large would be very rare events, but it is impossible to say that eruptions that large have never occurred.
Is Mount Ruiz still active?
Colombia’s broad, glacier-capped Nevado del Ruiz has dated eruptions going back 8,600 years, including observed activity since 1570. Ruiz remained quiet for 20 years after the deadly September 1985-July 1991 eruption until new explosive activity occurred from February 2012 into 2013.
What type of eruption was Mount Ruiz?
The Colombian volcano Nevado del Ruiz is an active stratovolcano with a history of generating deadly volcanic mudflows (lahars) from relatively small-volume eruptions. In 1595, a lahar swept down the valleys of the River Guali and the River Lagunillas, killing 636 people.