Teaching Geography: Workshop 2

Past Activity

After a major eruption in 1918, Tungurahua continued with minor activity until 1925.

Dormancy

Tungurahua is inactive from 1925 to September of 1998.

Earthquakes

Scientists at Ecuador's Instituto Geofisico (Geophysical Institute) monitor the volcano. The seismic network begins to register increased fracture-type earthquakes beneath Tungurahua.

Going Public

Tungurahua releases a column of steam thousands of feet into the air, leading to more earthquakes and increased sulfur emissions. The Geophysical Institute decides that it is time to go public with information about Tungurahua's activity.

Yellow Alert

The Geophysical Institute issues a Yellow Alert based on the detected increase in seismic activity.

Orange Alert

Because of the rapid changes in the volcano, scientists change the status of the alert from yellow to orange for the most vulnerable zones on the west and southwest sides of the volcano. The President of Ecuador comes to Baños to assess the situation.

Incandescence

Scientists at the Geophysical Institute begin to see incandescence, in addition to increasing seismicity and continuing gas emissions. These signs indicate that Tungurahua's eruption is imminent.

Evacuation

The President of Ecuador, overreacting to the orange alert, orders an evacuation. The military forces 25,000 tourists and residents to evacuate all areas surrounding Tungurahua in a mere 36 hours.

Explosions

Explosive eruptions begin at Tungurahua on November first, lasting through November 30 and peaking between November 16 and 25. Ash plumes rise to maximum heights, covering Baños in 0.5 mm of ash.

Mutiny

The displaced residents of Baños respond to news that soldiers are looting their homes. They violently throw off the military, later signing a truce with the governor pronouncing that they voluntarily return to the Baños and that the government is not responsible for their well-being.

Continuation

The alert status remains at orange, with continuing patterns of noisy ash-bearing eruptions, tremor, and elevated seismicity.

Decreasing Activity

Seismic reports show continuous mild activity with occasional lava fountaining. Explosions dwindle to about one-third of the frequency with which they occurred in January.

Restoration

At this point, 80% of Baños' residents have returned to their homes. The tourism industry has re-established itself as it was prior to the blasts.

The Tungurahua volcano has gone through a series of active and dormant periods in recent recorded history.

Using your mouse pointer, select dates on the timeline below to follow the volcano's activity --in a condensed format -- from 1773 to the present day.

Throat of Fire

Tungurahua means "throat of fire" in the local language. 1773 saw just one of more than 80 eruptions over the past 3000 years.

Past Activity

Major eruption in 1886.