and seismic hazards (Wright, 2002; Biggs et al., 2007). InSAR 
can map ground surface deformation immediately after an 
earthquake (i.e., post-seismic deformation), which yields 
important clues for inferring the properties of the Earth’s crust 
and upper mantle (Figure lc) (Biggs et al., 2006). InSAR is 
playing an increasingly important role in mapping triggered slip, 
which occurs during an earthquake on faults not involved in the 
main shock and is therefore extremely difficult to measure with 
conventional technology (Fialko et al., 2002). In addition, 
InSAR can identify blind faults from surface deformation 
patterns. Combined with seismology and other geophysical and 
geodetic measurements, InSAR can be expected to aid many 
breakthroughs in understanding the entire phase of the 
earthquake cycle (Wright, 2002). 
2.2 Mapping volcanic deformation 
SAR data acquired before and after a volcanic eruption can be 
used to image the co-eruptive deformation. Surface deformation 
data from InSAR can provide essential information about 
(g) Westdahl 
(h) Makushin 
(i) Seguam 
(j) Kiska 
(f) Akutan 
28.3 cm 
(g) Westdahl 
(h) Makushin \ 
(d) Korovin ' \ ^ • 
J JjsV; 
(f) Akutan 
(e) Okmok 
(b) Peulik. 
(a) Augustine 
# 
(c) Aniakchak 
Figure 2. InSAR deformation images of selected volcanoes in the Aleutian Islands, (a) InSAR image (1992-1993) of Augustine 
Volcano that reveals deformation associated with compaction of 1986 pyroclastic flow deposits (Lu et al., 2003a). (b) InSAR 
image (1996-1997) showing ~17 cm of episodic uplift of Peulik Volcano (Lu et al., 2002b). (c) An averaged InSAR image of 
Aniakchak Volcano showing that the caldera subsided about 13 mm/yr from 1992 to 2002 (Kwoun et al., 2006). (d) InSAR 
image of Korovin Volcano that shows more than 4 cm of inflation associated with the elevated seismicity from July to 
September 2006. (e) Deformation interferogram of Okmok Volcano showing deflation of about 1.2 m associated with the 1997 
eruption (Lu et al., 1998, 2000c, 2005a). (f) L-band JERS-1 InSAR image showing the complex deformation field at Akutan 
Volcano that accompanied an intense earthquake swarm in March 1996 (Lu et al., 2000a, 2005b). (g) InSAR image showing 
inflation of Westdahl Volcano, which occurred aseismically during 1993-1998 (Lu et al., 2000b, 2003d). (h) InSAR image of 
Makushin Volcano showing about 7 cm of surface uplift associated with a possible eruption in January 1995 (Lu et al., 2002c). 
(i) InSAR image of Seguam Volcano showing surface uplift of more than 6 cm during 1999-2000 (Lu et al., 2003a; Masterlark 
and Lu, 2004). (j) InSAR image showing subsidence of Kiska Volcano due to a change in the hydrothermal system during 
1999-2000 (Lu et al., 2002a). All interferograms are draped over DEM shaded relief images; areas without interferometric 
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magma dynamics 
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