Seismic exploration at Fuji volcano with active sources : The outline of the experiment and the arrival time data

Fuji volcano (altitude 3,776m) is the largest basaltic stratovolcano in Japan. In late August and early September 2003, seismic exploration was conducted around Fuji volcano by the detonation of 500 kg charges of dynamite to investigate the seismic structure of that area. Seismographs with an eigenfrequency of 2 Hz were used for observation, positioned along a WSW-ENE line passing through the summit of the mountain. A total of 469 seismic stations were installed at intervals of 250-500 m. The data were stored in memory on-site using data loggers. The sampling interval was 4 ms. Charges were detonated at 5 points, one at each end of the observation line and 3 along its length. The first arrival times and the later-phase arrival times at each station for each detonation were recorded as data. P-wave velocities in the surface layer were estimated from the travel time curves near the explosion points, with results of 2.5 km/s obtained for the vicinity of Fuji volcano and 4.0 km5/s elsewhere

A preliminary report of the gravity survey in Ross Island, Antarctica

Gravity surveys were carried out on Ross Island during the austral summer of 1982-1983. Twenty-one gravity stations were established in the summit area of Mount Erebus and eleven stations in the other area of Ross Island. The Bouguer gravity anomaly distribution shows a possibility of the maximum positive anomaly in the northeast side of the Erebus main crater, though the gravity stations are sparse there. This might be due to the fact that the structure of Mount Erebus is not a caldera type but nearly of the same type as the Kilauea Volcano of Hawaii Island and the O Sima Volcano of Japan