Fault control of subsidence.

Land subsidence increases the area in the Texas Coastal Zone which will be inundated by marine waters from hurricane flooding. Storm surge from a Carla- sized hurricane in 1976 would flood at least 25 square miles more land than Hurricane Carla did in 1961. Land subsidence in Harris and Galveston Counties results primarily from groundwater production. The two-county area is interlaced with active surface faults with topographic escarpments and surface faults with no topographic escarpments that control drainage patterns and create subtle photographic linear patterns. Some useful figures include: (1) Active surface faults and surface traces of extrapolated subsurface faults in Harris and Galveston Counties, Texas, followed by maps showing subsidence in the same areas, (2) and figures depicting fault control of subsidence and of the elevation of the piezometric surface in certain areas.