Comments: Semeru is one of the most active volcanoes in the region, erupting sometimes hundreds of times a week. Typically the plumes or ash clouds are low level and small in scale, and very difficult to see by satellite. The photos above and below were taken from a commercial flight at 33,000 ft on 23/10/04, by Gary Gibson of Environmental Systems and Services, Australia, and are shown with his kind permission. The altitude of the ash cloud is about 15,000 ft. A brownish haze behind the volcano shows where previous eruption clouds are dispersing. The photo is taken from the east.

Image Source: NOAA-15, 18 July 2000, visible

Comments: The examples above and below show the results from an experimental image enhancement. Above, we see a visible image with various features labelled. Below, the ash clouds from the same image have been thrown into sharp relief by looking at the extent of their difference from water clouds when subtracting two different infrared satellite channels. 'Normal' clouds show as black here. The red spots near Semeru and the volcano to the north are mostly silicates around the volcano peaks.

Image Source: NOAA-15, 18 July 2000, enhanced.

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August 1985

Image Source: NASA Space Shuttle, 4 August 1985. Image ID STS51F-35-19, annotated

Comments: This view across Java from the southwest shows more typical activity from Semeru, with a long, thin plume not much above the volcano level.

Comments: In 2001, Semeru (arrowed, with eruption plume) featured in an international advertising campaign for the Euro currency; the phrase "the EURO. Our money" appears to be originating from the Banda Sea in far eastern Indonesia (currency: the Rupiah).