A magnitude-6.1 quake Thursday evening has been followed by hundreds of small aftershocks and at least seven quakes powerful enough to send people running in panic from homes and businesses, including a magnitude-6.6 tremor Friday.
The Sandinista government has placed the country on red alert, the highest possible level, and is urging Nicaraguans to sleep outside their homes until further notice.
Life in Nicaragua, whose capital was devastated in 1972 by a magnitude-6.2 quake that killed nearly 10,000 people, has become a tense game of waiting between shakes.
In Santa Ana, a poor neighborhood a few blocks from the major fault line that crosses Managua and caused the 1972 quake, dozens of people took refuge in a bar and on the street outside after their shacks were damaged by the latest tremors.
On Sunday night, the country was hit by magnitude-4.6 and magnitude-5.6 quakes. On Monday morning, members of the 23 families sheltering at the bar moved chairs off the tables to make room for more people.
"We didn't sleep a wink last night," said Ana Maria Echaniz, 30. "It's continuous anxiety, fear that comes and goes all the time."
First lady Rosario Murillo, who is the government's spokeswoman, said the recent seismic activity had reactivated the Managua fault, frightening city residents with memories of the 1972 quake. The U.S. Geological Survey said it could not confirm that, but said it was common for large quakes to affect nearby faults, sometimes making them more liable to cause new quakes and sometimes less so.
"We have to live on constant alert," Murillo said Monday. "Follow our instructions. We're still in a state of high emergency."
A few hundred meters (yards) away, Daniela Artola, 56, checked the severely cracked walls of a motorcycle dealership that abuts her home. The building was one of the few in the neighborhood that survived the 1972 quake.
"We're watching it. We're scared, more than anything because of the memories of the past," she said. "The worst is the wind in the night. Every gust of wind puts us on alert again, because it breaks the silence."