WASHINGTON, D.C.: A strong 6.9-magnitude earthquake struck off the coast of central Chile late Tuesday but there was no immediate tsunami alert or reports of injuries or damage, US seismologists said. The epicenter of the quake was near the coast, about 93 kilometers northwest of Coquimbo, said the US Geological Survey (USGS). The Pacific Tsunami Warning Center said there was no tsunami threat from the quake, which struck at 8:54 pm (0154 GMT Wednesday) at a depth of 10 kilometers. Chile’s National Emergency Office said there were no reports of harm to people or any disruption to basic services or infrastructure. Less than an hour later, a 6.8-magnitude aftershock rattled the same region. Also centered off the coast some 97 kilometers west-northwest of Coquimbo, it hit at 0246 GMT Wednesday, again at a depth of 10 kilometers.