巴丹島
In 1998, volcanologists recorded seismic swarms which led them to form a monitoring network on Batan Island for several months. After the swarms of tremors had diminished, the temporary stations in Barangay San Joaquin in Basco, Batanes and another near the crater, were pulled out. Seismicity or any activity relating to Iraya is still monitored by the Basco Seismological Station.