HONOLULU—An earthquake at an active deep sea volcano off Hawaii shook the Big Island but didn’t appear to have any impact on other nearby volcanoes and no significant damage was reported. The U.S. Geological Survey’s Hawaiian Volcano Observatory said the magnitude-4.0 quake Wednesday night was located under Loihi seamount, about 20 miles southwest of the Island of Hawaii, also known as the Big Island. It occurred at a depth of 7 miles. USGS officials said moderate shaking could be felt across the Big Island but at that intensity no significant damage was expected. The earthquake did not generate a tsunami and it had no apparent effect on nearby Kilauea or Mauna Loa volcanoes. “We see no detectable changes in activity at the summits or along the rift zones of Loihi, Kilauea or Mauna Loa as a result of this earthquake,” said Ken Hon, head scientist at the USGS’s Hawaiian Volcano …