BackgroundGunung Tanggamus is of Quaternary age (van Bemmelen 1949b). Its products, which mostly consist of lavas, breccias, and tuffs of predominantly dacitic and andesitic composition, dominate the geology of the western part of the Lampung Province in southern Sumatra (Zulkarnain, 2011). Older Tanggamus products close to the main cone are generally pyroclastic breccias, consisting of porphyritic andesite and lapilli tuff. The younger products that make up the relatively undissected cone are of intermediate composition, and those deposits in the proximal zone surrounding the cone and in more distal regions are pyroclastic and laharic breccias and ignimbrites (Husein et al., 2015). The ignimbrites appear to be younger than the pyroclastic breccias (Husein et al., 2015). The lavas on Tanggamus are vesicular and porphyritic, and at about 1.4 million years old, are younger than the pyroclastic breccias and ignimbrites. The laharic breccias, consisting of porphyritic andesite and pumice, yielded an age of 1.5 Ma; however, field observations indicate that these units may be younger (Husein et al., 2015).
Source: Smithsonian / GVP volcano information
See also: Sentinel hub | Landsat 8