text: (CNN)Chile's Calbuco Volcano erupted again Thursday, marking the third time since last week, the National Service of Geology and Mining said. Gregorio Billikopf lives across Lake Llanquihue from the volcano has been photographing and videotaping the three eruptions and described Thursday's event as spectacular but not as severe as the two prior ones. "There is still smoke on and off, but nothing so dramatic (as before)," said Billikopf, a retired university adviser on agricultural issues. "On a good day I can see about eight volcanoes. "I understand that the rain that was announced for today would have been a disaster," he added. He lives in a rainy part of Chile, which he described as like a Garden of Eden. The explosion produced an extensive plume, but it was also described as smaller than the eruptions on April 22 and April 23, according to CNN Chile. Deputy Interior Minister Mahmud Aleuy said about 1,500 people were evacuated, and security measures will continue as "contingency plans are operating," CNN Chile reported Thursday. For the past several days, the geology agency has maintained there was a possibility of a third eruption as part of steadily declining seismic activity in the area. A 20-kilometer (12-mile) exclusion zone has been established around the crater, and Chilean authorities have been keeping residents away from that zone. Last week, military and police forces helped evacuate more than 4,400 residents, the Interior Ministry said then. The seismic event is sure to add to the volume of ash already spewed since the first eruption. Ash spread to Argentina in the second eruption, which occurred a day after the first. Evacuations in the region involved not only people but also animals. The volcanic debris has landed and piled up in some places to a depth of almost 2 feet, the Ministry of Interior and Public Safety said. New advisories say airborne ash could reach an altitude of 12,000 feet. There was no immediate information on the strength of the third eruption, but government officials have said the second, spectacular nighttime eruption was stronger than the first one. Last week in Ensenada, houses, trees and even sheep were blanketed gray with ash. People were removing salmon -- a staple of the local economy -- because of fears of contamination from ash and lava. Trucks were used to evacuate farm animals and pets. Authorities last week issued a red alert for the popular tourist towns of Puerto Montt and Puerto Varas in southern Chile. Last week, people were being evacuated to Puerto Montt on 22 buses and military trucks, the Interior Ministry said. Officials said that volcanic flows from Calbuco caused rising water levels in the Río Blanco. The first eruption set off a bit of a panic in the region. "At the beginning, it was small, and later, the cloud grew. And later, there was a huge cloud over you and true terror starts," a Puerto Montt resident said. Another person said: "It was impressive to see an enormous mushroom cloud, with the immense force of the volcano, and to see the ashes. At that point, there was a lot of panic, lots of chaos, traffic jams, people going to supermarkets, everyone looking for water, trying to take out money from the ATMs." Magma expanse under Yellowstone supervolcano more vast than thought . The eruption is a first for many in the region. The last major eruption was in 1962. There was a minor eruption in 1972. Calbuco also belched out a bit of gas and smoke in 1996. CNN's Shasta Darlington contributed from Sao Paolo, Brazil. CNN's Michael Pearson also contributed to this report.
target: "There is still smoke on and off," says resident with distant view .
  The volcano erupts for third time since April 22 .
  About 1,500 people are evacuated, an official says, according to CNN Chile .