He you go GLP, you should get an idea of how big this is (if you dont already)

FAULTING, SUBSIDENCE AND LAND LOSS IN COASTAL LOUISIANA (1999)
[link to www.coastalenv.com]


Page 54: Look in "Mega Block II" - find verret lake, look where the E-W growth system fault is. its just north of the L. Sands - Frenier (SW-NE fault).

Page 57:
"Vertical adjustments to gravity induced earth movement and isostatic down-warping also occur along fault planes.
Cumulative displacement on growth faults and episodic changes in subsidence rates support this conclusion. Much, if not most of the vertical adjustment takes place along fault planes. Therefore, fault induced or geotechnical subsidence, as it has been used in the literature, is a major contributing factor to relative sea level rise. This paper identifies the importance of fault movement, the locations and types of major faults, and identifies blocks bound by the
major faults...Geotechnical subsidence occurs as movement along circular patterns of faults, which circumscribe collapse features, and along linear growth faults. Collapse features may be induced by salt depletion at depth and/or sediment loading at the surface. Movement along growth faults occurs in response to compaction, geosynclinal downwarping and gravity slumping."

"The origin and locations of major growth faults are related to basement topography and earth crust movements. Once established they become zones of weakness where vertical displacement in response to sediment loading occurs. Cumulative displacement of beds indicates that some have been active since Cretaceous times. Thus, the down-thrown blocks of growth faults become depressions which "attract" deposition, and in turn cause movement
on the faults."

"coastal region is divided into a mosaic of massive fault-bound blocks. Movement of the blocks is similar to mass movement along the delta front, but on a larger scale and over a longer time period. Some blocks are moving and slumping into the deep Gulf of Mexico through a process of gravity induced slumping which is occurring on a massive scale along the continental margin.

"Until recently, fault movement in the coastal lowlands was masked and went unnoticed because of accretion processes. However, within the last 40 years the effects of fault
movement have become more evident because of increased rates of sinking and reduction of accretion processes. Fault traces have become visibly delineated by patterns of land loss and marsh deterioration."

"Baton Rouge Fault System, located along the rim of the
Gulf Salt Dome Basin, is active and has caused structural damage to building foundations and bridges. Some minor earthquake activity may be related to movement along this fault system. A zone of intensive faulting (Lake Borgne Fault Zone) occurs between the Lake Sand-Frenier and Mauvais Bois alignments."

THIS AREA INCLUDES ASSUMPTION PARISH