The South Pacific island nation of Vanuatu continues to be jolted by several moderate to strong earthquakes after a magnitude 7.1 temblor hit last week. Several earthquakes, including a 6.1 and a 6.0, hit Monday. Since the larger quake struck Friday there have been 20 temblors of magnitude 4.5 or above, according to the U.S. Geological Survey. Most have been centered near the 7.1 quake, which hit about 77 miles (124 kilometers) west of Port-Vila, Vanuatu’s capital. No tsunami warnings have been issued, and there have been no reports of injuries or damage. The region lies on the “Ring of Fire” — an arc of earthquake and volcanic zones that stretches around the Pacific Rim. About 90 percent of the world’s quakes occur in the region.