The Japanese government on Wednesday hosted a panel in Tokyo on allowing emergency "911" calls to be placed through social networks such as Twitter during natural disasters.

The national Fire and Disaster Management Agency held the event in central Tokyo, the first of three it plans to hold through March of next year. Panel participants included the head of Twitter Japan as well as officials from Yahoo Japan, Japanese social network Mixi, and NHN Japan, which runs the popular group chat application "Line." Representatives from government agencies and emergency services also attended.

"This is a discussion for when traditional voice-based infrastructure goes down during a natural disaster, to see if social networking can be used," said Yosuke Sasao, an official at the agency.

Twitter Japan head James Kondo tweeted from the event that he'd like to strengthen the service's ability to serve as a lifeline during crisis situations. Also Wednesday, the company's Japanese blog posted a series of entries on how to use Twitter during emergencies, including posting and searching for emergency and transport information, as well as calling for help and how users can provide updates about their condition.

"If your circumstances allow, please add #survived to your tweets. This will help when family and friends that are worried about you search on your welfare," one entry said.

As in other countries, a host of Japan's emergency services are currently accessible through telephone services, which include fixed-line, mobile, and IP-based telephone. The emergency number in the country is "119," which corresponds to the "911" number in the U.S. and "112" in much of Europe.

But during large-scale natural disasters, such as the massive earthquake and tsunami that hit Japan's east coast last year, voice networks often clog up under the dual strain of damaged infrastructure and a sudden surge of lengthy voice calls. The country also employs a system that blocks everyday users from phone networks to give emergency crews and government officials better access.

For many in Japan, social networks and online chat services were the only source of information in the hours after the disasters in March of last year, when much of the country was without power and phone lines and email services were overwhelmed.

In the months after the disaster, volunteers roamed shelters in hard-hit areas and posted pictures online of handwritten lists with survivors' names and locations, to help family get in touch. Services such as Google's Person Finder, a public database with information on individuals in disaster areas, were widely used by individuals and government organizations to keep track of survivors.

The use of social networks like Twitter jumped in the days after the disasters. A survey by local marketing firm IMJ two weeks later found a surge in new users signing up mainly to get information about their friends and family.

Japan's official government agencies are also increasingly using services such as Twitter to make official announcements. On Wednesday the Tokyo Fire Department started its official account, @Tokyo_Fire_D.

The next meeting on using social networks to make emergency calls is due to take place in November.