A cluster of tremors off Japan’s northeastern coast has raised alarms among seismologists, as a new government study warns that up to 199,000 people could be killed if a magnitude-9 earthquake strikes. The most recent quake, a magnitude 4.9 offshore tremor recorded on Sunday evening near Miyako in Iwate prefecture, was small and caused no reported damage. Yet authorities are urging residents to remain vigilant and review their evacuation plans after a succession of smaller offshore quakes in...