A pair of aftershocks only six seconds apart provoked a brief panic among citizens in Chile, but no tsunami warning was issued and no injuries or damage have been reported.
Some residents of Concepcion started running for high ground when an aftershock to Saturday's destructive earthquake was followed just six seconds later by another. The U.S. Geological Survey says Wednesday's temblors had preliminary magnitudes of 5.9 and 6.0, respectively. The 6.0 jolt was the strongest measured since Sunday.
Fire officials used loudspeakers to assure residents that no tsunami was imminent. Concepcion was badly damaged by Saturday's magnitude-8.8 quake.