A powerful magnitude 7.8 earthquake that struck southern Mindanao on Monday morning served as a stark reminder of the Philippines’ vulnerability to a major quake in Metro Manila, disaster experts said. The tremor, which triggered tsunami warnings along the southern coast, left collapsed buildings, damaged homes and debris-strewn streets in its wake. At least 19 people were killed and more than 130 injured, with scores still missing, local disaster authorities said. For disaster planners, the...