Archaeoseismology and Palaeoseismology in the Alpine ... - Tierra

CONCLUSIONS
Analysis of the 1798 photographs recollected on the
Guadalquivir Diapiric Ridge and the Cadiz Contornite
Channel in the Gulf of Cadiz has allowed to identify 5861
chimneys lying scattered in dense concentrations over the
seabed. The fallen chimneys present a regular spatial
distribution in a NW‐SE direction. The basal morphology
of them shows common characteristics of an angular
breakage associated with flexo‐traction processes. These
characters are very significant because they are a strong
indication for the seismic origin of chimneys rupture.
On the basis of the geological characteristics of the area
and the mechanical properties of the carbonate chimneys
it has been determined from ground motion prediction
equations a first order approximation to the most likely
seismic scenario. We have particularly looked at two
different scenarios: (A) an earthquake produced by a fault
located right under the chimneys field (Rjb=0 km) with a
minimum Mw 7.2; and, (B) an earthquake located about 6
km far from the chimneys field with a Mw=7.8
earthquake. Probably this fault was the Guadalquivir Bank
Fault, that present a NE‐SW trend and it is very close of
the study area.
Acknowledgements: We thank all those who participated in the
research cruises of the TASYO project, especially the Main
Researches of TASYO project, Luis Somoza (Instituto Geológico y
Minero de España, IGME) and Victor Díaz‐del‐Río (Instituto
Español de Oceanografía, IEO) and the captains and crews of the
research vessel R/V Cornide de Saavedra. This research was
funded by the Spanish Marine Science and Technology Program,
under the CONTOURIBER Project CTM2008‐06399‐C04‐01/MAR.
It is also a contribution to the project CONSOLIDER‐INGENIO
2010 CSD2006‐0041‐TOPOIBERIA.
References
Ambraseys, N.N., Douglas, J. (2003). Near‐field horizontal and
vertical earthquake ground motions. Soil Dynamics and
Earthquake Engineering, 23, 1‐18.
Ambraseys, N.N., Douglas, J., Sarma, S.K., Smith, P.M. (2005).
Equations for the estimation of ground motion from shallow
crustal earthquakes using data from Europe and the Middle
East: Horizontal peak ground acceleration and spectral
acceleration. Bulletin of Earthquake Engineering, 37, 1‐53.
Boore, D.M., Joyner, W.B., Fumal, T.E. (1997). Equation for
estimating horizontal response spectra and peak acceleration
from Western North American Earthquakes: a summary of
recent work. Seismological Research Letters, 68, 128‐153.
Buforn, E., Sanz de Galdeano, C., Udías, A. (1995).
Seismotectonics of the Ibero‐Maghrebian region.
Tectonophysics, 248, 247‐261.
Cadorin, J.F., Jongmans, D., Plumier, A., Camelbeeck, T., Quinif, Y.
(2000). Modelling of speleothem rupture. Proceedings of the
Conference HAN 2000‐Potential for large earthquakes in low
seismic activity regions of Europe. Han‐sur‐Lesse, Belgium, 27‐
30.
Campos, M.L. (1991). Tsunami hazard on the Spanish coasts of
the Iberian Peninsula. Science of Tsunami Hazards, 9 (1), 83‐
90.
Castagna, J. P., Batzle, M. L. y Eastwood, R. L. (1985). Relationship
between compressional wave and shear wave velocities in
clastic silicate rocks. Geophysics, (50), 571‐581.
1 st INQUA‐IGCP‐567 International Workshop on Earthquake Archaeology and Palaeoseismology
86
Cunha, T. (2006). Gravity anomalies over the SW Protuguese
Margin and their tectonic implications. 5º Simposio sobre a
Margem Ibérica Atlântica, Aveiro.
Díaz‐del‐Río, V., Somoza, L., Martínez‐Frias, J., Mata, M.P.,
Delgado, A., Hernández‐Molina, F.J., Lunar, R., Martín‐Rubí,
J.A., Maestro, A., Fernández‐Puga, M.C., León, R., Llave, E.,
Medialdea, T., Vázquez, J.T. (2003). Vast fields of hydrocarbon‐
derived carbonate chimneys related to the accretionary
wedge/olistostrome of the Gulf of Cádiz. Sedimentary
Processes and Seafloor Hydrocarbon Emission on Deep
European Continental Margins. Marine Geology, 195 (1‐4),
177‐200.
Douglas, J. (2003). Earthquake ground motion estimation using
strong‐motion records: A review of equations for the
estimation of peak ground acceleration and response spectral
ordinates. Earth‐Science Reviews, 61(1–2), 43–104.
Fernández‐Puga, M.C. (2004). Diapirismo y estructuras de
expulsión de gases hidrocarburos en el talud continental del
Golfo de Cádiz. Tesis de Licenciatura, Facultad de Ciencias del
Mar, Universidad de Cádiz.
Gràcia, E., Dañobeitia, J., Vergés, J., Bartolomé, R. (2003a).
Crustal architecture and tectonic evolution of the Gulf of Cadiz
(SW Iberian margin) at the convergence of the Eurasian and
African plates. Tectonics, 22(4).
Gràcia, E., Dañobeitia, J., Vergés, J., Córdoba, D., PARSIFAL Team
(2003b). Mapping active faults offshore Portugal (36ºN‐38ºN):
implications seismic hazard assessment along the southwest
Iberian margin. Geology, 31(1), 83‐86.
Hernández‐Molina, F.J., Llave, E., Stow, D.A.V., García, M.,
Somoza, L., Vázquez, J.T., Lobo, F.J., Maestro, A., Díaz del Río,
V., León, R., Medialdea, T., Gardner, J. (2006). The contourite
depositional system of the Gulf of Cádiz: A sedimentary model
related to the bottom current activity of the Mediterranean
outflow water and its interaction with the continental margin.
Deep‐Sea Research II, 53, 1420‐1463.
Kramer, S.L. (1996). Geotechnical Earthquake Engineering.
Prentice‐Hall, 653 p.
Martins, I., Mendes, V.L.A. (1990). Contribuçao para o estudo da
sismicidade de Portugal comtinental. Universidade de Lisboa,
Instituto Geofísico do Infante D. Luís, publicaçao nº 18, 70 p.
Smith, W.H.F., Sandwell, D.T. (1997). Global sea floor topography
from satellite altimetry and ship depth soundings. Science, 277
(5334), 1956‐1962.
Terrinha, P., Pinheiro, L.M., Henriet, J.P., Matias, L., Ivanov, M.K.,
Monteiro, J.H., Akhmetzhanov, A., Volkonskaya, A., Cunha, T.,
Shaskin, P., Rovere, M. (2003). Tsunamigenic‐seismogenic
structures, neotectonics, sedimentary processes and slope
instability on the southwest Portuguese Margin. Marine
Geology, 195(1‐4), 55‐73.
Zitellini, N., Chierici, F., Sartori, R., Torelli, L. (1999). The tectonic
source of the 1755 Lisbon earthquake and tsunami. Annali di
Geofisica, 42,(1).
Zitellini, N., Mendes, L.A., Córdoba, D., Dañobeitia, J., Nicolich, R.,
Pellis, G., Ribeiro, A., Sartori, R., Torelli, L., Bartolomé, R.,
Bortoluzzi, G., Calafato, A., Carrilho, F., Casoni, L., Chierici, F.,
Corela, C., Correggiari, A., Della Vedova, B., Gràcia, E., Jornet,
P., Landuzzi, M., Ligi, M., Magagnoli, A., Marozzi, G., Matias, L.,
Penitenti, D., Rodríguez, P., Rovere, M., Terrinha, L., Vigliotti,
L., Zahinos‐Ruiz, A. (2001). Source of the 1755 Lisbon
earthquake and tsunami investigated. Eos Trans. AGU, 82 (26),
285‐291.
Zitellini, N., Rovere, M., Terrinha, P., Chierici, F., Matias, L.,
BIGSETS Team (2004). Neogene Through Quaternary Tectonic
Reactivation of SW Iberian Passive Margin. Pure and Applied
Geophysics, 161, 565‐587.
Zitellini, N., Gràcia, E., Matias, L., Terrinha, P., Abreu, M.A.,
DeAlteriis, G., Henriet, J.P., Dañobeitia, J.J., Masson, D.G.,
Mulder, T., Ramella, R., Somoza, L., Díez, S. (2009). The quest
for the Africa–Eurasia plate boundary west of the Strait of
Gibraltar. Earth and Planetary Science Letters, 280, 13‐50.