The picture-postcard scenery of heavily forested hillsides and placid inlets has become pregnant with menace.
Boris Pualuan, whose family has run a general store across from the central plaza since 1928, is among the rattled. "Some people are sleeping all day," he said. "And some people don't sleep at all."
Sister Augusta Pedrielli is an Italian-born Catholic nun who has lived here for more than four decades. "People are afraid Puerto Aisen is going to disappear," she said.
The daily tremors began in late January and now number more than 7,000. The shakes culminated in a 6.2 magnitude earthquake on April 21 beneath nearby Aisen Fjord that sent chunks of hillside plunging into the inland waterway, generating waves that swept away fishermen, salmon farm workers and others. Three people died and seven others are missing, presumed dead.
The killer waves dissipated short of town, but the ground here trembled mightily, cracks opened in the earth, debris tumbled from mountains, and the town's signature suspension bridge swayed like a Slinky. Puerto Aisen's geologic vulnerability was suddenly exposed, alarming residents accustomed to tranquillity.
As much as 15% of the population of 30,000 here and in the nearby port of Puerto Chacabuco has left, officials said.
"This emergency is not over: We don't even know if the worst is over," said Carlos Aranda, chief of seismology at the University of Chile.
Many of the people who live along the seismic-volcanic "ring of fire" that encircles the Pacific Ocean learn to live with the near-certainty that a significant earthquake will strike in their lifetime. Few expect six months of nerve-jangling jolts.
The shaking continues, scientists said, though recently it has not been as perceptible to residents.
The mystery about what exactly is going on here has drawn experts from across the globe to this nook of the Chilean coast, about 800 miles south of Santiago, the capital. Scientists debate whether magma below ground may be at play in a zone where active volcanoes are found to the north and south.
Three tectonic plates clash near the Chilean coast, making the region one of the most tectonically active in the world. The largest measured earthquake, a 9.5 magnitude temblor, struck in 1960 near Valdivia, about 400 miles north of here, according to the U.S. Geological Survey.
The April 21 earthquake occurred on a long-identified fault system, Liquiñe Ofqui, which stretches for about 750 miles along the Chilean Andes.
But some parts of the moon have been better mapped than this stretch of the Pacific coast. And the quake destroyed much of the measuring equipment placed in the fjord.
"We're starting from way far behind," lamented Andres Pavez, a Chilean geophysicist who is part of the multinational team hoping to save lives by determining what's next.
The prevailing uncertainty has fanned fears and imaginations along this rainy, fog-shrouded coastal strip.
People have gotten used to sleeping in their clothes, drawing the curtains and keeping their kids home from school.
They report broken marriages, increased alcoholism and depression, and a sense of impending doom.