HR: 1340h
AN: T13C-1376    [Abstracts]
TI: Resolving Normal Fault Growth and Slip Rates Through Time Using Sequence Stratigraphy; Gulf of Corinth, Greece.
AU: * Cotterill, C J
EM: cjc3@soc.soton.ac.uk
AF: Southampton Oceanography Centre, University of Southampton , Southampton, SO14 3ZH United Kingdom
AU: McNeill, L C
EM: lcmn@soc.soton.ac.uk
AF: Southampton Oceanography Centre, University of Southampton , Southampton, SO14 3ZH United Kingdom
AU: Bull, J M
EM: J.M.Bull@soton.ac.uk
AF: Southampton Oceanography Centre, University of Southampton , Southampton, SO14 3ZH United Kingdom
AU: Henstock, T
EM: then@soc.soton.ac.uk
AF: Southampton Oceanography Centre, University of Southampton , Southampton, SO14 3ZH United Kingdom
AU: Stefatos, A
EM: A.Stefatos@upatras.gr
AF: Laboratory of Marine Geology and Physical Oceanography, University of Patras, Patras, 26500 Greece
AU: Collier, R
EM: R.Collier@earth.leeds.ac.uk
AF: School of Ocean and Earth Sciences, Univeristy of Leeds, Leeds, LS2 9JT United Kingdom
AU: Papatheodorou, G
EM: george.papatheodour@upatras.gr
AF: Laboratory of Marine Geology and Physical Oceanography, University of Patras, Patras, 26500 Greece
AU: Ferentinos, G
EM: gferen@upatras.gr
AF: Laboratory of Marine Geology and Physical Oceanography, University of Patras, Patras, 26500 Greece
AB: The Gulf of Corinth is the most actively extending continental rift zone in Europe. The Aigion Fault, in the western gulf, has 3 main onshore and 3 offshore segments, each of $\sim$1-2km length. It is a young north-dipping fault, and is active concurrently with, and overlaps, the Western Eliki Fault to its south. Detailed swath bathymetry of the eastern fault tip shows that the offshore segments form the southern boundary to a half graben, with multiple synthetic and antithetic splays associated with segment tips. The fault trace appears to propagate beyond the shelf edge. 3D analysis of sequence stratigraphy, using high-resolution marine seismic reflection data, has enabled quantification of fault growth spatially and temporally. Sequence stratigraphic markers relating to the post-lowstand transgressive surface of $\sim$11ka, and the final progradational fan delta topsets of 60-80ka form the boundaries between two distinct packages, enabling quantification of fault slip rates. The maximum observed vertical displacement rate at the fault tip is $\sim$1.2 $\pm$ 0.2mm yr$^{-1}$, averaged over the last 11ka. The displacement rate is seen to increase between 80-11ka and 11ka-present. This may be due to fault propagation and the interaction and overlap between the Aigion and Eliki systems. More detailed analysis will enable determination of displacement rate variations on timescales of thousands of years. Combining these data with onshore geomorphological studies, such as marine terrace uplift, allows correlation of activity across the broader fault system over a similar timescale. This study enables analysis of earthquake behaviour on this fault system over multiple cycles, highlighting evidence for possible clustering of events, and short-term variation in slip rate. It shows that high-resolution seismic imaging taken across submarine fault zones can provide significant additional information that contributes to the understanding of seismological activity and fault growth on normal faults in a continental rift setting.
DE: 7221 Paleoseismology
DE: 7223 Seismic hazard assessment and prediction
DE: 8010 Fractures and faults
DE: 8105 Continental margins and sedimentary basins
DE: 3025 Marine seismics (0935)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting