Kawah Putih: Two craters adorn the summit of Patuha Volcano. The dry crater of Kawah Patuha lies 600 meters northwest of Kawah Putih, a crater lake with approximately 8 meters of water depth. Kawah Putih crater lake represents a relatively stable volcanic system, with no records of magmatic or phreatic activity since A.D. 1600. Nevertheless, magmatic activity manifests itself in Kawah Putih as the hyperacid lakewater solution that results from condensation of SO2, H2S, and HCl gases near the lake bottom.
Hydrothermal water-rock interactions in the Kawah Putih system constitute a present-day example of volcanic ore-deposit formation. Precipitation of native sulfur and other sulfides from lake waters have accumulated as extensive sulfur-rich sediments on the lake bottom. These sediments were mined during the first half of the 20th century and comprised 90% of Indonesia's sulfur production at that time. Abundant seepage of Kawah Putih's lakewaters into fractures is another mechanism of hydrothermal ore formation in the volcano.
Seepage of lakewater from Kawah Putih is also a concern to human health. This seepage acidifies the flank springs of Patuha volcano. The flank springs feed the Ciwidey and Citarum Rivers, whose waters are used by local people for irrigation.
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