At least 57 people died on the island of Bohol, where the 7.2-magnitude quake's epicenter struck, according to Bohol police chief Senior Superintendent Dennis Agustin.
The national disaster agency had previously reported 16 deaths on the neighboring islands of Cebu and Siquijor.
The 7.2-magnitude quake caused centuries-old churches and modern buildings to crumble, while major roads were also ripped open and blocked by landslides.
"I was fast sleep when suddenly I woke up because my bed was shaking. I was so shocked, I could do nothing but hide under the bed," Janet Maribao, 33, a receptionist in Cebu, told AFP.
The affected areas are famed for their idyllic white sands and turquoise waters.
Civil defense office spokesman Reynaldo Balido Jr. and others involved in the relief and rescue operations warned the death toll would climb, with the full extent of the damage yet to be assessed.
Nevertheless, they expressed relief the earthquake occurred on a public holiday, meaning there were fewer people than normal in many of the major buildings that suffered damage.
The quake struck at 08:12 (0012 GMT) near Balilihan, a town of about 18,000 people on Bohol, at a depth of 20 kilometers (12 miles), the USGS reported.
The town lies across a strait about 60 kilometers from Cebu.
Cebu, with a population of 2.5 million people, is the political, economic, educational and cultural center of the central Philippines.
It hosts the country's busiest port and largest airport outside of the capital Manila. It also has a major ship building industry.
A university, a school and two shopping malls sustained major damage in the quake.
Three of the people who died in Cebu were crushed to death in a stampede at a sports complex, where poor people had gathered to collect regular government cash handouts, according to the the provincial disaster council chief, Neil Sanchez.
"There was panic when the quake happened and there was a rush toward the exit," Sanchez told AFP.
He said two other people were killed when part of a school collapsed on a car they had parked in, while four others died at a fish market that crumbled.
The Philippines' oldest church, Cebu's Basilica Minore del Santo Nino, was badly damaged, according to Balido.
It was first built in the 1500s by Spanish colonizers, although its current stone structure dates back to the 1700s.
A church in Bohol that was built in the early 1600s also collapsed, according to Robert Michael Poole, a British tourist who was visiting the area.
"It's absolutely devastated... the entire front of the church has collapsed onto the street," Poole told AFP by telephone.
However he said there was nobody in the church at the time of the quake.
Aside from its beaches, Bohol is famous for its more than 1,000 small limestone "Chocolate Hills" that turn brown during the dry season.
One of the main tourist venues there, the Chocolate Hills Complex, was severely damaged and may be beyond repair, according to Delapan Ingleterra, head of a local tourist police unit.
"There are huge cracks in the hotel and there was a collapse of the view deck on the second floor," he told AFP. However he said no-one was injured there.
Tuesday's quake was followed by at least four aftershocks measuring more than 5.0 in magnitude.
The epicenter was 629 kilometers from Manila.
The Philippines lies on the so-called Pacific Ring of Fire, a chain of islands that are prone to quakes and volcanic eruptions.
More than 100 people were left dead or missing in February last year after an earthquake struck on Negros island, about 100 kilometers from the epicenter of Tuesday's quake.
The deadliest recorded natural disaster in the Philippines occurred in 1976, when a tsunami triggered by a magnitude 7.9 earthquake devastated the Moro Gulf on the southern island of Mindanao.
Between 5,000 and 8,000 people were killed, according to official estimates.
source: www.abs-cbnnews.com
