In fact, seismologists said the likelihood of future quakes cannot be predicted with certainty.
Thursday's 3.5 quake, which mirrored Wednesday's 3.5 shaker centered beneath a Vallejo mobile home park, is better seen as a reminder that residents should be prepared for a major earthquake expected in the San Francisco Bay Area sometime in next 30 years.
"It's not too alarming," Charles Real of the California Geological Survey told the newspaper.
"It always puts us on alert to watch the area."
Vallejo and nearby Benicia are between the well-known San Andreas and Hayward faults, but the south Solano area is also home to many lesser-known faults, including the Green Valley fault, which runs under Suisun Bay.
Boatwright agreed that the back-to-back quakes in the same area was unusual, but said it did not necessarily indicate that further seismic activity was imminent.
"We usually see a larger event followed by smaller aftershocks," Boatwright told the newspaper.
"The fact that it is a double event is less normal," he said.
"But we certainly saw something like that in Berkeley in October."
Berkeley was struck by a 4.0 quake on the Hayward fault on Oct. 20, followed by a 3.8 aftershock later that day and a 3.6 aftershock one week later.