A 7.4 earthquake that struck near the Philippines was followed by a powerful second quake on Friday, Oct. 10, killing at least seven and damaging buildings, authorities said.

The initial quake struck offshore from the Davao Oriental province in the southern Philippines at 9:45 a.m. local time on Oct. 10. In the wake of that 7.4 quake, tsunami warnings were issued to surrounding coasts, but were later canceled.

The large second quake struck at about 7:12 p.m. and new tsunami warnings were issued. Authorities urged people in the Davao Oriental, Surigao Del Sur and Surigao Del Norte provinces to evacuate to higher ground or move inland. Authorities in the Philippines said it was a 6.9-magnitude quake while the U.S. Geological Survey measured it at 6.7.

As authorities warned more strong aftershocks could come, search-and-rescue teams were preparing to assess areas with damage when it was safe to do so, President Ferdinand Marcos Jr. said.

At least seven people were killed in the quakes, civil defence official Ednar Dayanghirang said. At least two died in Mati City near the epicenter, civil defense official previously Karlo Puerto told Reuters. In Manay, there were early reports of damage to buildings and bridges.

"We are working round the clock to ensure that help reaches everyone who needs it," Marcos said in a statement. "Let us continue to look out for one another and pray for the safety of all our countrymen."

The 7.4 quake was among the strongest to hit the Philippines in recent years. The nation experiences more than 800 quakes in an average year. On Sept. 30, a 6.9 earthquake killed at least 74 people on the central island of Cebu, causing the bell tower of a centuries-old church to crumble.

Richie Diuyen, a disaster official in Manay, told Reuters the Oct. 10 quake lasted 30 or 40 seconds and called it "the strongest earthquake I ever felt."

Photos of a mall in Butuan City on the southern island of Mindanao show a gaping hole in the wall and debris around cars in the parking lot outside. At the airport in Davao City, people waited outside for clearance to enter, photos showed. A video posted to social media and verified by Reuters showed an overturned cabinet in one building in Davao City.

What impact does a 7.4 quake have?

Magnitude measures the strength of an earthquake. The 7.4-magnitude quake on Oct. 10 is considered a major earthquake that can cause serious damage to a community. See the ranking scale:

  • Below 2.5: Generally not felt.
  • 2.5 to 5.4: Minor or no damage.
  • 5.5 to 6.0: Slight damage to buildings.
  • 6.1 to 6.9: Serious damage.
  • 7.0 to 7.9: Major earthquake. Serious damage.
  • 8.0 or greater: Massive damage. Can destroy communities

Contributing: Elizabeth Weise, USA TODAY; Reuters

(This story has been updated to add new information.)

This article originally appeared on USA TODAY: Powerful aftershock follows 7.4-magnitude earthquake in the Philippines, killing 7

Reporting by Jeanine Santucci, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect