One Year Later: the Tohoku, Japan Earthquake and Tsunami

Today marks the one year anniversary of the Tohoku, Japan Earthquake and Tsunami. The earthquake was a magnitude 9.0 and was the most powerful known earthquake ever to have hit Japan, and one of the five most powerful earthquakes in the world since modern record-keeping began in 1900. The earthquake triggered powerful tsunami waves that reached heights of up to 133 feet and traveled up to six miles inland. The earthquake shifted the Earth on its axis by estimates of between four and 10 inches. Referred to as Japan’s 3/11 disasters, the earthquake and tsunami killed almost 20,000 people and caused a significant nuclear radiation leak.

Immediately after the earthquake, the National Oceanic and Atmospheric Administration’s (NOAA) Pacific Tsunami Warning Center and the West Coast and Alaska Tsunami Warning Center both issued tsunami warnings for Hawaii, the U.S. West Coast, Alaska and the island territories in the Pacific. A tsunami warning is the highest level of alert so DEM got to work, gathering in the early morning hours at our Emergency Operations Center and began issuing public alerts and warnings about the tsunami expected to hit the California coast line (visit the San Francisco tsunami inundation map to know which areas in San Francisco can be impacted by a tsunami). Working from pre-dawn until post-dusk, it was a very long day for DEM and our fellow city departments and agencies that played a role in the response. Thankfully, the tsunami caused little damage. We were lucky. 

The activated DEM Emergency Operations Center.

While the tsunami generated by the Tohoku Earthquake which hit Hawaii and the West Coast caused relatively minor damage, it reminds us of the need to be aware of how tsunami alerts and warnings are issued. There are various alerting tools available, including the City’s Outdoor Public Warning siren system; Emergency Alert System messages, which are broadcast on radio and television stations; and AlertSF, our text-based message system that delivers emergency information to cell phones and other text-enabled devices, as well as email accounts. If you live in San Francisco and have not yet registered for AlertSF, we urge you to sign up at www.alertsf.org.  DEM also will use its social media channels to issue public alerts and warnings, so if you are on Facebook and Twitter, please ‘like’ and ‘follow’ us.

The last week in March is Tsunami Preparedness Week (March 25-31, 2012) and this year’s theme is Nature’s Warning; meaning, a strong earthquake felt in a low-lying coastal area is a natural warning of possible, immediate danger, so keep calm and quickly move to higher ground away from the coast. And the 106th anniversary of the 1906 San Francisco Earthquake and Fire is April 18, 2012. We hope these events along with the first year anniversary of the Tohoku Earthquake and Tsunami are serious reminders to think about your earthquake and tsunami preparedness (visit 72hours.org to learn more about how to be prepared for emergencies) and inspire us to become better prepared and more resilient as a community.

Drop, cover and hold on is the safest thing to do during an earthquake.

A strong earhthquake felt in a low-lying coastal area is a natural warning of possible, immediate danger. Keep calm and quickly move to higher ground away from the coast.

It is important to remain on high ground. Waves from a tsunami may arrive eight hours or longer after the earthquake.

We conclude this DEM Blog post with a moving video about the Tohoku, Japan Earthquake and Tsunami entitled: Arigato from Japan.