Semilir eruption located in/on physical feature Java
The Semilir eruption was a major volcanic event which took place in Indonesia during the Early Miocene. This eruption formed the Semilir Formation and Nglanngran Formation. These two geological formations are in the Southern Mountains of East Java. The eruption created two formations  which consist  of mostly pyroclastic rock (minor lava flows). It has incredible thickness (at least 1,200 m (3,900 ft)). In contrast,  The Toba supereruption only formed 600 m (2,000 ft) ignimbrite. The estimated Semilir eruption age date by isotope method is 21 million years ago.
situated in/on physical feature positioned in/on physical feature found in/on physical feature placed in/on physical feature situated on/at physical feature