The investigation has been performed on damages of wooden houses from the earthquakes in northern Miyagi on July 26, 2003. In particular, structural characteristics of wooden houses having open floor plans and old construction year were examined in detail. Although these houses were considered to be vulnerable to earthquakes, there were a lot of houses damaged lightly or moderately. From the investigation, it is found that the typical wooden houses in the northern Miyagi area have tall hanging mud-walls. The yield base shear coefficients range from 0.3 to 0.7 in both the longitudinal and transverse directions. The hanging mud-walls bear from 10% to 50% in the total base shear. Therefore, the hanging walls play very important role as well as full-height mud walls in the seismic performance of wooden houses with open floor plan in this area.
