A series of moderate to strong earthquakes that have struck Alaska’s western Aleutian Islands and offshore areas comprise what scientists call a “swarm,” but the state’s earthquake monitors say the seismic events should not cause residents to worry. There were no immediate reports of damage or injuries in the area of Adak, Amchitka and Kiska islands some 1,350 miles west of Anchorage. Of the three islands, only Adak Island is inhabited with a population of about 300 people. The Alaska Earthquake Center reports nine quakes measuring at least magnitude 5.0 striking on or near the islands and in a cluster offshore to the south. Three of the quakes measured 6.0 or stronger, with the biggest a 6.3 temblor that struck offshore.