MANILA (AFP, REUTERS) - Two strong earthquakes struck parts of the Philippines and Indonesia's Sumatra island on Monday (March 14), but there were no immediate reports of damage.
A third quake hit near Hong Kong, leading to a record number of local residents to report they felt tremors.
In the Philippines, a 6.4-magnitude quake hit about 110km off Morong in Bataan province on Luzon island at 5.05am, with residents in nearby Manila woken by their buildings shaking.
The quake occurred at a depth of 11km, the United States Geological Survey (USGS) said.
The Pacific Tsunami Warning Centre said there was no tsunami risk from the quake.
Shallow quakes tend to do more damage than deep tremors, but the Philippine Institute of Volcanology and Seismology said damage was not expected.
"It's strong and it's shaking as if it's dancing sideways," said Lieutenant Aristotle Calayag, acting police chief of Lubang town in Occidental Mindoro, an island off Luzon.
"The people are used to earthquakes like this so they didn't rush outside or panic," he said.
Morong police chief Captain Michelle Gaziola told Agence France-Presse that the quake was "a bit strong but it was brief".
"We're okay. Most people are still asleep."
Shortly after, a magnitude-6.7 quake shook west Sumatra.
USGS said the quake's epicentre was 167km west of Pariaman city near Kepulauan Batu at a depth of 21.8km. The epicentre was 197km from Padang, the capital and largest city in West Sumatra province.
The quake sent residents fleeing from their homes, but no damage or victims were reported immediately.
“The earthquake was felt for one minute at moderate intensity as people got panicked and fled their homes,” said the National Disaster Mitigation Agency in an initial report.
The tremor was followed by a series of strong aftershocks, according to the Indonesian geophysics agency.
The Pacific Tsunami Warning Centre initially said that the earthquake could potentially generate a tsunami affecting the Indian Ocean region, but it soon lifted the warning.
“Based on the latest report, there is no damage and victims, but we continue monitoring. The jolt was strongly felt in the South Nias island,” said Mr Agus Wibisono, the head of Nias’ search and rescue office.
The Philippines and Indonesia are regularly rocked by quakes because of their location on the Pacific “Ring of Fire”, an arc of intense seismic activity that stretches from Japan through South-east Asia and across the Pacific basin.
Hong Kong's magnitude-4.1 quake meanwhile struck at 2.29am about 92km northeast of the city and near the coast of South-east China, according to the Hong Kong Observatory.
Authorities received about 8,000 reports of minor shaking, the highest number since record keeping began in 1979.
The shaking intensity was estimated to be at level 4 on the Modified Mercalli Intensity scale, which means that it could rattle windows and doors, and cause hanging objects to swing.
Earthquakes are rarely felt in Hong Kong. Only 85 earthquakes have been reported in the city since 1979 – an average of about two a year – and none of them ever led to a direct casualty, according to the Hong Kong Observatory.