Following the approximately 8.9-magnitude earthquake that hit northeast of Japan's capital, Tokyo, a Pacific tsunami alert has been issued for countries with coastlines in and around the Pacific Ocean, including Indonesia and the Philippines.
Tokyo is one of the world's eight most populous cities located on a tectonic fault-line, according to the Belgium-based Centre for Research on Epidemiology of Disasters.
The Japan Meteorological Agency raised alerts for a potential 10m high tsunami, putting officials in Indonesia, who experienced the 2004 tsunami, on high alert.
"We have been informed it will hit us at 6pm [11am GMT], " deputy of emergency management at the National Agency for Disaster Management, Sutrisno, who, like most Indonesians, goes by one name, told IRIN.
Officials in the three provinces expected to be hardest hit - Malaku, North Sulawesi and Papua - are prepared to evacuate residents if needed, he added.
"We have already called them [officials] to give them the warning that we just received from the national climate and meteorology office. We do not know how big the tsunami will be so we have to prepare."
He said members of Indonesia's national rapid response team had also been put on alert for deployment overseas if requested by Japan's government.
Indonesia is the most disaster-prone country in the world, according to the UN Office for the Coordination of Humanitarian Affairs; in 2009 alone, it experienced 469 earthquakes with a magnitude of five or higher - more than any other nation.
The head of the Philippines National Disaster Risk Reduction and Management Council, Benito Ramos, said a 1m-high tsunami was expected to hit the country's eastern Pacific-facing seaboard between 4:46pm and 7pm local time (8.46am and 11am GMT), but thus far the country has only been hit with minor waves.
"We have alerted all PNP [Philippine National Police] and military in these areas and advised all seagoing vessels not to set sail, especially the small vessels used by fishermen," he said.
Communities are still on high alert and have been evacuated from eastern shorelines, according to Harold Cabunoc, military spokesman for the eastern Bicol region.
"We are hoping for the best. We cannot give you details on how many have been evacuated, but everyone is cooperating."
The country is hit by an average of 20 cyclones annually and is still recovering from unseasonal fatal flooding that affected almost two million people earlier this year.