The FCDO now advises against all travel to within 5km of the crater of the volcano in Lumajang Regency, East Java, after it erupted on Sunday (4 December), sending ash a kilometre and a half into the sky.
It also advises against travel to the southeast area of Mount Semeru along the Besuk Kobokan river, approximately 13km from the crater, and 500m from any Besuk Kobokan riverbank.
Local authorities have set an alert status of level 4 and are warning of the potential for pyroclastic flows and lava flows along rivers, tributaries and valleys around Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar and Besuk Sat.
