Abstract
We investigated the strong ground motions and the damage of buildings near the surface faults of the 2011/04/11 Fukushima-ken-Hama-Dori earthquake (Mw 6.6). First, we confirmed that the strong ground motions from this normal fault were equivalent and/or more than the thrust fault, by using the strong motion records and the attenuation curves. We also checked that the ground motions near the surface faults were larger than those of the 2011/03/11 Great Tohoku earthquake (Mw 9.0), and therefore, the most of building damage was caused by the Fukushima-ken-Hama-Dori earthquake. Next, we investigated that the 191 buildings near the surface faults (within 500 m), and obtained the following conclusions. The most of severe damage was caused by the surface faulting and the subsequent ground failure. Among 9 buildings above the surface faulting, only one building was overturned. The building was a tall gate in a Budhism temple and fell on the side by the surface fault of 60 cm dislocation, because the columns were not anchored to the foundations. As for the other buildings, the damage by the strong ground motion was negligible. That is, the rate of heavy damage (Damage Grade 4 and upper) was less than 2%, which corresponds to JMA Intensity 5- and 6+, even though the most of buildings seemed very old and weak.
