The Weekly Volcanic Activity Report: October 22-28, 2026

Watchers New eruptive activity or unrest: Chikurachki, Russia | Kikai, Japan | Nevados de Chillan, Chile | Piton de la Fournaise, France | Whakaari/White Island, New Zealand. Continuing rruptive sctivity, unrest, or other observations: Ahyi, United States | Aira, Japan | Ambae, Vanuatu | Ambrym, Vanuatu | Etna, Italy | Great Sitkin, United States | Ibu, Indonesia | Karangetang, Indonesia | Kilauea, United States | Krasheninnikov, Russia | Langila, Papua New Guinea | Lewotolok, Indonesia | Manam, Papua New Guinea | Marapi, Indonesia | Mayon, Philippines | Merapi, Indonesia | Purace, Colombia | Sabancaya, Peru | Semeru, Indonesia | Sheveluch, Russia | Suwanosejima, Japan | Taal, Philippines | Yasur, Vanuatu. New activity/unrest Chikurachki, Russia 50.324°N, 155.461°E; Elev. 1,781 m The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that an explosive eruption at Chikurachki likely began at 0520 on 26 October based on satellite data and advisories issued (VAAC). Ash plumes rose as high as 5.6 km (18,400 ft) a. s. l. and drifted 240 km E. At 1735 the Aviation Color Code was raised to Orange (the second highest level on a four-color scale). No additional explosions were recorded over the next few days. At 2226 on 28 October the Aviation Color Code was lowered to Yellow. Dates are based on UTC; specific events are in local time where noted. Geological summary: Chikurachki, the highest volcano on Paramushir Island in the northern Kuriles, is a relatively small cone constructed on a high Pleistocene edifice. Oxidized basaltic-to-andesitic scoria deposits covering the upper part of the cone give it a distinctive red color. Frequent basaltic Plinian eruptions have occurred during the Holocene. Lava flows have reached the sea and formed capes on the NW coast; several young lava flows are also present on the E flank beneath a scoria deposit. The Tatarinov group of six volcanic centers is located immediately to the south, and the Lomonosov cinder cone group, the source of an early Holocene lava flow that reached the saddle between it and Fuss Peak to the west, lies at the southern end of the N-S-Chikurachki-Tatarinov complex. The Tatarinov centers are extensively modified a more complex structure. Tephrochronology gives evidence of an eruption around 1690 CE from Tatarinov, although its southern cone contains a sulfur-encrusted crater with fumaroles that were active along the margin of a crater lake until 1959. Kikai, Japan 30.793°N, 130.305°E; Elev. 704 m The Japan Meteorological Agency (JMA) reported that an eruption at Iodake Crater (at Satsuma Iwo-jima, a subaerial part of Kikai’s NW caldera rim) was recorded at 0207 on 17 May, the first since . An ash-and-gas plume rose 400 m above the crater rim and drifted S.