|Duration of observation:||1992 - 2004|
|Inferred cause of deformation:||Magmatic|
|Characteristics of deformation:|
Broad deformation observed at Trident also covers the vicinity of Martin and Mageik. Between 1992 – 2000, uplift of 5–10 mm/yr was observed, and inspection of individual interferograms suggests that most deformation occurred during 1997–2000. Between 2000 – 2004, averaged deformation images show that the inflation near Martin, Mageik and Trident continued at 4–7 mm/year, slightly lower than the results for 1997–2000. This inflation has been modelled using a spheroid and sill source to account for the elongate shape of the deformation field. The source location is constrained to the summit and eastern flank of Mageik, with dimensions ranging between 10 – 20 km and depths ranging from 5 – 15 km. The average rate of volume increase since 1995 is 0.008 km³/yr. The inflation pattern is consistent with gravity surveys of the area which reveal a low density gravity anomaly in the region. These observations suggest the presence of a crustal magma body that is probably responsible for the inflation signal.
|Reference:||Lu, Z., and Dzurisin, D., 2014, InSAR imaging of Aleutian volcanoes: Chichester, UK, Springer-Praxis, 390 p.|
|Reference:||Kienle, J. (1970). Gravity traverses in the Valley of ten-thousand smokes Katmai National Monument, Alaska. Journal of Geophys- ical Research,75, 6641–6649.|
|Reference:||U.S. Geological Survey Alaska Volcano Observatory (AVO) website|
The peaks of Trident. Source: R. McGimsey, U.S. Geological Survey AVO website