All information contained in these reports is preliminary and subject to change. The press reported that more than 940 earthquakes had been recorded by 14 April. Tremor episodes were not recorded and surface activity was not observed on the island or the surrounding sea. Strong felt seismicity but no surface changes High levels of seismicity . A total of 670 high-frequency earthquakes were felt by the end of April, including nine of JMA intensity IV, and a M 4.3 event on 31 March.
Solid columns represent felt events.
A solid square marks the JMA weather station. A total of 24 earthquakes was detected at Iriomote-jima Weather Station, on the NW coast of the island. Diagonal lines mark the area of the August 1992 swarm. A second, more severe swarm began on 17 September, centered a few kilometers N of the island and about 20 km NE of the August swarm. Epicenters migrated towards the island, and by November, the source area encompassed the northern coast.