Even in Lawrence, thousands of miles away from the massive earthquake and tsunami that rocked Japan, many of us woke up this morning to find the world a different place than it was when we went to bed last night – even if we didn’t have a friend, family member or co-worker in some way affected by the disaster. And for many of us, the way we found out about what had happened while we were asleep was via social media: a friend’s Facebook post, a retweet of a news update, even our own tweets about the developing situation.

A few years (and a different employer) ago, I remember sitting in a big corporate meeting listening to executives debating what the purpose was of getting on this whole Twitter bandwagon, wondering exactly how long this social media stuff was going to stick around, exactly how much value to individuals and corporations it was all going to offer. In the midst of a major news event like today’s, we’ve got a pretty definitive answer.

On the scene in Japan, with severe disruptions to infrastructure presenting major barriers to getting the word out, social media has been critical to getting the word about about survivors and casualties. CNET reports that “carriers were limiting voice calls on congested networks, with NTT DoCoMo restricting up to 80 percent of voice calls” and that, even with equally spotty Internet in many areas, social networks have been pushed to the fore due to their ability to broadcast a status update to a wide audience with a few clicks.

Tweets on the #sendai hashtag (used primarily right after the quake – currently the major hashtags in use are simply #japan, #earthquake, #tsunami, etc.) have included everything from eyewitness photos to retweets from local and international news sources to, heartbreakingly, individuals trying to find information on loved ones they call out by name or Twitter handle. Facebook, while a distant second in Japan to social network Mixi, is posting user comments about Japan at a rate of dozens per second, as well as a running post stream on the official Facebook Japan page with a focus on foreigners, visitors and others who may not be aware of other sources of info. And as tsunami waves and other disruptions have reached Hawaii and the Americas, the social media dialogue is shifting to those areas’ key media outlets, tweeters, bloggers and Facebook users.

In addition to the links above – and by no means a definitive list – here are some social media sources we’ve been keeping an eye on today. If you’ve been using social media to keep up to date on the disaster in Japan and elsewhere, where are you going for information? Let others know where to look by posting in the comments.

• Google’s Crisis Response page for the quake includes the much-discussed Person Finder feature as well as transport information, details on blackout areas and a map displaying areas of shelter in Tokyo.

• Storyful.com, currently in beta, is earning its stripes today for curating news from a wide variety of sources.

• YouTube’s CitizenTube is gathering an astonishing amount of citizen-produced video related to the disaster, especially eyewitness accounts.

• Tweeter @willmcguinness has been using recently-launched curation tool Storify to aggregate news and tweets about the disaster here.

• Tweeter @ProducerMatthew, in northern California, is posting updates from the west coast in addition to aggregating info from Japan.

• BBC News is aggregating material from a variety of social media sources.

• And while it’s not strictly social media, here’s a guide to the details behind how earthquakes are classified and how tsunamis work.