Tengger Caldera volcano (Eastern Java, Indonesia) - Smithsonian / USGS Weekly Volcanic Activity Report for 23 December-29 December 2020 (New Activity / Unrest)
The Alert Level remained at 2 (on a scale of 1-4), and visitors were warned to stay outside of a 1-km radius of the crater.
Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)
From: Global Volcanism Program, 2020. Report on Tengger Caldera. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 23 December-29 December 2020. Smithsonian Institution and US Geological Survey.