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| | CVO Menu - Three Sisters Vicinity - West Uplift - Information March 18, 2002 |
 | | The uplift was discovered by a satellite radar imaging technique during the spring of 2001, which showed that the ground surface had risen about 10 cm (4 inches) from 1996 to 2000. |
 | | In this case, surveys in 1985, 1986, and 2001 revealed a tilt pattern caused by uplift of an area centered ~5 km (3 miles) west of the summit of South Sister, which is visible in the upper left. |
 | | In addition to continued or accelerating uplift, precursors to an eruption would include earthquakes, typically swarms of small events generated by fracturing of rock as magma moves upward, and large emissions of volcanic gases, such as carbon dioxide, which is released from the magma. |
| vulcan.wr.usgs.gov /Volcanoes/Sisters/WestUplift/information_18march2002.html (655 words) |
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