Attenuation of peak ground acceleration (PGA) and peak ground velocity (PGV) of statistical Green's functions with Mw=5.2 calculated by different kinds of Q models and envelope models is compared with previous empirical attenuation relations. The attenuation of the statistical Green's function calculated by the region-specific Q model and envelope model based on scattering theory for subduction-zone earthquakes proposed by Satoh (2004, 2006) agrees with the region-specific empirical attenuation relation for subduction-zone earthquakes. On the other hand, Boore's (1983) envelope model tends to overestimate the empirical PGAs and PGVs as larger hypocentral distances are. Satoh et al's (1994) envelope model underestimates them by nearly 50 % in the hypocentral distances of less than 100 km.

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The practical structural health monitoring system is suggested aiming to detect certainly the occurrence of damage and to identify the portion with the degree of damage. Our system is highly reliable and simple of low cost adopting new sensors which translate the measurements to the damage indices and transmit in the minimum amount of data. The developed smart AE (acoustic emission) sensor is useful for local monitoring detecting the crack of concrete, and new smart VA (vibration analyzing) sensor is used for global monitoring by arresting the change in dynamic properties of the building structure. The wireless network using the standard ZigBee provides with the reduced consumption of electricity, and is expected to realize multi-hop transmission and mutual communication of sensors in the near future.

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The questionnaire survey was conducted to clarify effective explanation of grades of seismic capacity using probability of damage. The panels living in Yokohama City, Kawasaki City or 23 Wards of Tokyo who were in their thirties to forties, and who wanted home ownership were selected and 759 valid answers were obtained. Questions regarding seismic risk perception and preference of seismic capacity of a house were asked. As a result, it was observed that the panels overrated seismic risk and demanded various seismic capacities. Additionally, it was revealed that explanation using the probability of damage in relation to seismic intensity was effective, and that a house with high seismic capacity was preferred even after information on risk of seismic damage, which might remove the bias of the overrated seismic risk, and on additional cost to improve seismic capacity were provided.

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In the Niigataken-Chuetu earthquake occurred on October 23, 2004, the JMA seismic intensity scale 6 was recorded at many seismic stations. Especially at Kawaguchi, Kawaguchi-machi seismic station, JMA seismic intensity scale 7 was recorded for the first time since introduction of seismic intensity meters. Strong ground motion records with building damage data around the seismic stations make us possible to investigate correlation between damage to buildings and strong ground motion characteristics.
We carried out damage investigation around the seismic stations where high JMA seismic intensity scale were recorded. We did not find heavily damaged buildings except for around the Kawaguchi-machi, JMA Ojiya and K-NET Ojiya seismic station in spite of high JMA seismic intensity scales and PGAs (peak ground accelerations).
We investigated correlation between damage to buildings and strong ground motion characteristics using observed strong ground motion records. We found that the very short period, less than 0.5 sec., dominated many records whose JMA seismic intensity scales and PGAs are high but which did not bring about heavy damage to buildings. On the contrary, the 1-2 sec. period region dominated in the Kawaguchi-machi record which brought about heavy damage to buildings.

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