LOS LLANOS DE ARIDANE, Canary Islands—Residents on Spain’s La Palma island braced Wednesday for the possibility of bigger earthquakes that could compound the damage from a volcano spilling lava more than five weeks since it erupted. Seismologists said a 4.6 magnitude earthquake shook the island a day after they recorded a 4.9 magnitude quake that was the strongest so far of the hundreds that have occurred under La Palma since the volcano’s Sept. 19 eruption. So far, the earthquakes have either been small enough or far enough under La Palma to do no harm, other than adding to the anxiety of the island residents. The Tuesday earthquake was felt up to 60 miles (96 kilometers) away on three other segments of the Canary Islands, an archipelago off northwest Africa. “The scientific committee has been warning for more than a week that we could see earthquakes, given their recent depth of …