A series of earthquakes have shaken a region of ocean off the west coast of the US. Scientists have detected a cluster of 11 earthquakes, ranging in magnitude from 2.8 to 5.6 on the Richter scale. The cluster occurred on the seabed at the Juan de Fuca tectonic plate, around six miles (10km) underwater. This plate forms part of the Cascadia subduction zone, which runs from Northern California to British Columbia. Previous studies have warned this geological spot of weakness has the potential to deliver an earthquake much stronger than the infamous San Andreas fault. Seismologists say a full rupture along the 650-mile-long (1,000 km) offshore fault could trigger a 9.0 magnitude earthquake and an accompanying tsunami.