Taken from ANN:

The premise of the project is the 70% or higher possibility that a magnitude 7.0 earthquake will occur in Tokyo in the next 30 years. The anime will depict what would happen if an 8.0 earthquake took place. The story will center on Mirai, a middle school freshman girl who goes to Tokyo’s artificial Odaiba Island for a robot exhibition with her brother Yutaka at the start of summer vacation. A powerful tremor emanates from an ocean trench, the famed Tokyo Tower and Rainbow Bridge crumble and fall, and the landscape of Tokyo changes in an instant. With the help of a motorcycle delivery woman named Mari who they meet on Odaiba, Mirai and Yutaka strive to head back to their Setagaya home in western Tokyo.
OP and ED: YouTube - [HD] Tokyo Magnitude 8.0 OP & ED

This series has a mellow tone, with sudden dramatic scenes, and heart-wrenching moments that last longer than the standard anime scene.

This show is currently airing in Japan, which means that it is out in Fansubs, I'm not too sure if it is liscenced yet, I looked but couldn't find anything. When, if it gets liscenced be sure to watch it from their legal channels.

This show is very realistic in that it takes a closer look at the human psyci and how it deals with problem after problem.