The Mw=6.7 Northridge earthquake hit the Los Angeles area on January
17, 1994. The co-seismic slip on the south dipping thrust that did not
reach the surface increased the elevation of the ground by as much as 50
cm (Hudnut et al., 1996). Between December, 1993 and May, 1995, ERS-1 was
placed on a non-global coverage, 3-day repeat orbit, which did not cover
the Los Angeles area. The first interferogram of the earthquake produced
with ERS-1 data was made by combining images taken in 1993 with images
acquired after May 1995, when ERS-1 returned to a global coverage mode.
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Left panel: ERS-1, 3-pass interferogram of the western Los Angeles Basin covering the period between 8 November, 1993 and 6 December, 1995. The Northridge earthquake co-seismic displacement dominates the signal in the interferogram, which includes almost 2 years of post-seismic deformation (see Heflin et al., 1997). One color cycle represents here 5.6 cm of ground displacement in the direction of the satellite. Grey areas are where phase change information is lost because of temporal decorrelation. Changes occurring in the vegetation canopy and earthquake-triggered landslides are the main reasons of decorrelation in the mountain areas. White lines depict profiles shown in right panel. Right panel: Line of sight ground displacement along profiles AA' and BB' in left panel. Sections where profiles are segments of straight lines correspond to areas of decorrelation in left panel.