In the years before the 1883 eruption, seismic activity around the Krakatoa volcano was intense, with earthquakes felt as far away as Australia. Beginning on 19 May 1883, steam venting began to occur regularly from Perboewatan, the northernmost of the island's three cones. Eruptions of ash reached an estimated altitude of 6 km (20,000 ft) and explosions could be heard in New Batavia (Jakarta) away.