moderate explosions in the volcano, which is 135 kilometers (85 miles) south-east of the capital Quito, have generated ash, hot rock and gas which is falling on to nearby villages.
Authorities have issued an orange alert - the second-highest warning level - for towns near the volcano.
A statement from the Geophysical Institute in Quito read, "During the overnight and early morning hours, there continued to be a series of explosive events and signs of quaking and (lava) emission."
The first eruption from the Tungurahua volcano generated a column of ash around two kilometers (1.24 miles) high, which fell over various communities in the area, including the tourist city of Banos.
explosion generated the largest column of ash, measuring nearly five kilometers (3.1 miles) tall, above the 5,023-meter (16,479-foot) crater.
Residents reported hearing a roaring sound so loud that it shook their windows. Some said that it sounded like cannon fire.
, regional director for the government’s emergency agency says officials have prepared shelters and were working to evacuate any people in danger on Tuesday.
Tungurahua, which means "Throat of Fire" in the indigenous Quechua language, was dormant for a long period up until it became active again in 1999.
At that time, several communities near the volcano, including Banos with 15,000 people, were forced to evacuate and residents were only able to return to their homes a year later.
Eruptions peaked in 2006, killing six people in a Chimborazo village.