This page preserves the essential scientific context from a long-running volcano activity log. It summarizes agency observations about ash, lava, seismicity, gas and ground deformation without presenting old alert levels as current instructions.
26 September–3 October 2018
Regional observatories and volcanic-ash advisory centers documented activity at several systems. Satellite imagery, seismic measurements, thermal cameras and field observations supplied different parts of the picture.
Kerinci, Indonesia
Advisories for 28–30 September and 2 October placed ash near 4.3 km above sea level, moving generally west and southwest.
Langila, Papua New Guinea
Satellite analysis on 29 September indicated an ash plume near 2.4 km above sea level drifting northeast.
Piton de la Fournaise, Réunion
The continuing eruption showed stable tremor. A growing cone ejected spatter while much of the lava traveled through tubes before reappearing downstream.
Sarychev Peak, Russia
A satellite image from 22 September showed a thermal anomaly. The aviation color code in the historic report remained Orange.
Semisopochnoi, Alaska
Elevated seismicity alternated between continuous and intermittent tremor. No ash was identified above the low cloud layer in the cited satellite data.
Veniaminof, Alaska
Incandescence, elevated surface temperature and tremor supported evidence of an eruption. Lava advanced down the summit cone while minor ash dispersed.
Soputan, Sulawesi
Monitoring data showed a rise in seismic indicators and summit temperature in early October. The historic report recorded an eruption on 3 October with a dense ash column, followed by additional emissions. Hot material was observed around the summit and volcanic debris moved down the northeast flank. Authorities expanded the restricted area in the direction considered more exposed at that time.
5–11 September 2018
Etna, Sicily
Activity included summit gas release and intermittent Strombolian explosions at several craters. Some events generated localized ash near the vent and the Valle del Bove, while incandescent material generally remained inside crater boundaries.
Anak Krakatau, Indonesia
Satellite observations on 8 September indicated ash at roughly 4.9–5.5 km above sea level. Lower plumes were reported on 9–10 September. The historic agency guidance maintained a restricted radius around the crater.
Veniaminof, Alaska
Low-level ash emissions, increased seismicity and a strengthening thermal signal led the observatory to raise its 2018 aviation and volcano alert classifications. Subsequent imagery indicated lava fountaining and a lava flow on the southern flank within the summit caldera.
Regional field notes
Manam, Papua New Guinea
The August eruption affected crops, homes and drinking-water supplies on the remote island. Initial assessment and monitoring were complicated by disrupted communications between island instruments and the observatory. The episode illustrated how damaged infrastructure can delay both scientific interpretation and assistance.
Campi Flegrei, Italy
Field observations from the Naples area emphasized how closely communities and infrastructure overlap the caldera. The archive noted a long eruptive history and the 1538 Monte Nuovo eruption, underscoring why land deformation, seismicity and gas are monitored together.
Kīlauea, Hawaiʻi
By late August 2018, summit collapse had extensively altered the caldera and portions of Crater Rim Drive. The change followed magma movement into the lower East Rift Zone. Field teams documented subsidence, fractures and displaced blocks while activity at the fissure system had diminished markedly.
Fuego, Guatemala
Heavy rainfall remobilized loose volcanic material in late August, producing lahars in established channels. Reports described ash, large blocks and woody debris moving along ravines and tributaries. Workers nearby were moved away as a precaution.
Merapi, Indonesia
Drone imagery showed a new lava dome developing within the older summit dome. Monitoring reports tracked changes in estimated volume and growth rate while retaining the historic exclusion zone then in effect.
What monitoring signals meant in these reports
Seismicity
Earthquake swarms and tremor can indicate fracturing, fluid movement or sustained eruptive processes, but require local context.
Ash observations
Ground reports, cameras and satellites help estimate plume altitude and direction for aviation and nearby communities.
Thermal anomalies
Elevated temperatures may reveal exposed lava or a hot vent, although cloud and sensor resolution can limit interpretation.
Ground deformation
Inflation or subsidence can reflect pressure and magma movement. It is interpreted alongside gas and seismic measurements.
Filed under: Daily volcano activity.