REGION: The center of the earthquake was just off the Japan coastline. The region of impact mostly had an elevation lower than 500 ft above sea level., this allowed for the tsunami to easily reach low lying areas. The largest wave had a height of 133 feet.
IMPACTS: This 9.1 magnitude earthquake was the largest this area has ever seen. The region suffered catastrophic losses, which included deaths, economic impacts, and regional damage. The total count from this earthquake and tsunami reached 15,894 deaths, 6,152 injured, and 2,562 people missing. Some land subsidized as much as 4 feet.
Japan is the most prepared country in the world, and it's readiness likely saved thousands of lives. Schools larger than two stories have evacuation chutes, the kids have earthquake drills often, and are taught what to do in an earthquake. Televisions after a large quake are automatically tuned to an updated earthquake warning system. Buildings in the quake swayed heavily but did not collapse, this is due to the building codes that must be followed in order to be built. You can see the results of that quake swaying the buildings in Tokyo below.
Here you can see the swaying of buildings in Tokyo after the quake. They received shocks upwards of a 7.9 magnitude quake from the original 9.1 earthquake.
The most well known secondary disaster after the earthquake was the tsunami that caused more than 90% of the deaths. Other lesser known disasters included landslides, major dehydration to over 1 million people in the first 2 weeks, power loss to over 4 million people, and radiation affecting food and soil both inside and outside the disaster zone. People had to wear masks around Sendai and Tokyo in order to protect themselves from harmful radiation levels. Aftershocks from this quake had caused major issues to the people trying to clean up after the disaster. The largest aftershock was a 7.9 quake on the same day. In its self, a magnitude 7.9 quake can cause major destruction. In total there was over 11,000 aftershocks from the quake, 5,000 being in the first year. Since the quake and its secondary disasters, Japan has taken major precautionary measures in preparation for more major quakes. They updated their building codes, and have created more efficient evacuation codes for tsunami prone areas. New technology will give people more time to evacuate from tsunamis, and new technology is being developed to predict the next earthquakes and where they will strike.
The earthquake lasted a total time of 6 minutes, and the hypocenter had a depth of 29km below sea level.
The government has estimated the damage from the earthquake and tsunami to be at 16-25 trillion yen. The top estimate would make it the world's costliest natural disaster. It includes damage to roads, homes, factories and other infrastructure, but excludes lost economic activity from power outages and costs arising from damage to the Fukushima nuclear power plant, as well as the impact of swings in financial markets and business sentiment.
The earthquake happened along the most active plate in the world, the pacific. It ran across a ocean to continental convergent boundary line which causes slip motions colliding onto each other. This was a mega thrust earthquake that was caused by built up tension on the fault.
The population of Japan is 127.3 million and is distributed largely in urban areas. 78% of the country lives in an urban landscape and only 22% in rural areas. Japan has a mostly mountainous topography, however the location of the earthquake had large impacts to Japan because of the low lying coastline. Less than 10% of the deaths occurred during the earthquake.