Interseismic Strain Accumulation Near Lisbon (Portugal) From Space Geodesy

Abstract The Lisbon Metropolitan Area, Portugal, has been affected by several destructive earthquakes nucleating both along the offshore Africa-Eurasia plate boundary and on onshore inherited intraplate faults. Using a dense GNSS dataset coupled with PSInSAR analysis, we provide new evidence of sinistral simple shear driven by a NNE-SSW first-order tectonic lineament. PSInSAR vertical velocities corroborate qualitatively the GNSS strain-rate field, showing uplift/subsidence where the GNSS data indicate contraction/extension. We propose the presence of a small block to the W of Lisbon moving independently toward the SW with a relative velocity of 0.96 ± 0.20 mm/yr, whose boundaries are part of a complex and as yet poorly constrained strike-slip fault system, possibly rooting at depth into a simpler basement fault. Comparison between geodetic and seismic moment-rates indicates a high seismic coupling. We show that the contribution of intraplate faults to the seismic hazard in the LMA is more important than currently assumed.

FCT - Fundação para a Ciência e a Tecnologia, Lisbon. Grant Number: EXCL/GEO-FIQ/0411/2012
Agencia Española de Investigacion. Grant Number: RTI2018-093874-B-100
AGEO - Platform for Atlantic Geohazard Risk Management. Grant Number: EAPA_884/2018

Altamimi, Z., Rebischung, P., Métivier, L., & Collilieux, X. (2016). ITRF2014: A new release of the International Terrestrial Reference Frame modeling nonlinear station motions. Journal of Geophysical Research: Solid Earth, 121, 6109– 6131. https://doi.org/10.1002/2016JB013098
Alves, T. M., Gawthorpe, R. L., Hunt, D. W., & Monteiro, J. H. (2003). Cenozoic tectonosedimentary evolution of the western Iberian margin. Marine Geology, 195, 75– 108. https://doi.org/10.1016/S0025-3227(02)00683-7
Anderson, J. G., & Luco, J. E. (1983). Consequences of slip rate constraints on earthquake occurrence relations. Bulletin of the Seismological Society of America, 73, 471– 496. https://doi.org/10.1785/bssa0730010045
Arthaud, F., & Matte, P. (1977). Late palaeozoic strike-slip faulting in southern Europe and Northern Africa: Result of a right-lateral shear zone between the Appalachians and the Urals. The Geological Society of America Bulletin, 88, 1305– 1320. https://doi.org/10.1130/0016-7606(1977)88<1305:lpsfis>2.0.co;2
Bennett, R. A., Wernicke, B. P., & Davis, J. L. (1998). Continuous GPS measurements of contemporary deformation across the northern Basin and Range province. Geophysical Research Letters, 25(4), 563– 566. https://doi.org/10.1029/98gl00128
Burgmann, R., Rosen, P. A., & Fielding, E. J. (2000). Synthetic aperture radar interferometry to measure Earth's surface topography and its deformation. Annual Review of Earth and Planetary Sciences, 28, 169– 209. https://doi.org/10.1146/annurev.earth.28.1.169
Cabral, J. (2012). Neotectonics of mainland Portugal: State of the art and future perspectives. Journal of Iberian Geology, 38(1), 71– 84. https://doi.org/10.5209/rev_jige.2012.v38.n1.39206
Canora, C., Vilanova, S. P., De Pro-Diáz, Y., Pina, P., & Heleno, S. (2021). Evidence of surface rupture associated with historical earthquakes in the lower Tagus valley, Portugal. Implications for seismic hazard in the Greater Lisbon Area. Frontiers of Earth Science, 9. https://doi.org/10.3389/feart.2021.620778
Canora, C., Vilanova, S. P., Ostman, G. M. B., Carvalho, J., Heleno, S., & Fonseca, J. F. B. D. (2015). The eastern lower Tagus valley fault zone in central Portugal: Active faulting in a low-deformation region within a major river environment. Tectonophysics, 660, 117– 131. https://doi.org/10.1016/j.tecto.2015.08.026
Costa, A. C., Sousa, M. L., & Carvalho, A. (2008). Seismic zonation for Portuguese national annex of Eurocode 8. In Proceedings of the 14th World Conference on Earthquake Engineering, China.
Cunningham, W. D., & Mann, P. ( (2007). Tectonics of strike-slip restraining and releasing bends. In W. D. Cunningham, & P. Mann (Eds.), Tectonics of strike-slip restraining and releasing bends (Vol. 290, pp. 1– 12). Geological Society, London, Special Publications. https://doi.org/10.1144/sp290.1
Curtis, M. L. (1999). Structural and kinematic evolution of a Miocene to Recent sinistral restraining bend: The Montejunto massif, Portugal. Journal of Structural Geology, 21, 39– 54. https://doi.org/10.1016/s0191-8141(98)00095-9
Custódio, S., Dias, N. A., Carrilho, F., Góngora, E., Rio, I., Marreiros, C., et al. (2015). Earthquakes in Western Iberia: Improving the understanding of lithospheric deformation in a slowly deforming region. Geophysical Journal International, 203, 127– 145.
Dickson, A. J. (1992). A regional seismic interpretation of offshore Portugal (M.Sc. Thesis). U.K: University of Durham.
Farolfi, G., Piombino, A., & Catani, F. (2019). Fusion of GNSS and satellite radar interferometry: Determination of 3D fine-scale map of present-day surface displacements in Italy as expressions of geodynamic processes. Remote Sensing, 11, 394. https://doi.org/10.3390/rs11040394
Fernandes, R. M. S., Ambrosius, B. A. C., Noomen, R., Bastos, L., Wortel, M. J. R., Spakman, W., & Govers, R. (2003). The relative motion between Africa and Eurasia as derived from ITRF2000 and GPS data. Geophysical Research Letters, 30, 1828– 1840. https://doi.org/10.1029/2003gl017089
Ferretti, A., Prati, C., & Rocca, F. (2000). Non-linear subsidence rate estimation using persistent scatterers in differential SAR interferometry. IEEE Transactions on Geoscience and Remote Sensing, 38(5), 2202– 2212. https://doi.org/10.1109/36.868878
Fonseca, A. F., Zêzere, J. L., & Neves, M. (2020). The Arrabida Chain: The Alpine Orogeny in the vicvinity of the Atlantic ocean. In G. Vieira, J. L. Zêzere, & C. Mora (Eds.), Landscapes and Landforms of Portugal, World Geomorphological Landscapes (pp. 273– 278). Springer Nature. https://doi.org/10.1007/978-3-319-03641-0_21
Herring, T. A. (2003). MATLAB Tools for viewing GPS velocities and time series. GPS Solutions, 7582(3), 194– 199. https://doi.org/10.1007/s10291-003-0068-0.583
Herring, T. A., King, R. W., Floyd, M. A., & McClusky, S. C. (2018). Introduction to GAMIT/GLOBK, Release 10.7. Cambridge, UK Massachusetts Institute of Technology.
Hubbard, R. J. (1988). Age and significance of sequence boundaries on Jurassic and early Cretaceous rifted continental margins. Bulletin: American Association of Petroleum Geologists, 72(1), 49– 72. https://doi.org/10.1306/703c81c8-1707-11d7-8645000102c1865d
Justo, J. L., & Salwa, C. (1998). The 1531 Lisbon earthquake. Bulletin of the Seismological Society of America, 88(2), 319– 328.
Lange, D., Kopp, H., Royer, J.-Y., Henry, P., Çakir, Z., Petersen, F., et al. (2019). Interseismic strain build-up on the submarine North Anatolian fault offshore Istanbul. Nature Communications, 10, 3006. https://doi.org/10.1038/s41467-019-11016-z
Lastras, G., Arzola, R. G., Masson, D. G., Wynn, R. B., Huvenne, V. A. I., Huhnerbach, V., & Canals, M. (2009). Geomorphology and sedimentary features in the Central Portuguese submarine canyons, western Iberian margin. Geomorphology, 103(3), 310– 329. https://doi.org/10.1016/j.geomorph.2008.06.013
Masson, F., Chery, J., Hatzfeld, D., Martinod, J., Vernant, P., Tavakoli, F., & Ghafory-Ashtiani, M. (2005). Seismic versus aseismic deformation in Iran inferred from earthquakes and geodetic data. Geophysical Journal International, 160, 217– 226. https://doi.org/10.1111/j.1365-246X.2004.02465.x
Molnar, P. (2020). The brittle-plastic transition, earthquakes, temperatures, and strain-rates. Journal of Geophysical Research: Solid Earth, 125e2019JB019335. https://doi.org/10.1029/2019JB019335
Montenat, C., Guery, F., Jamet, M., & Berthou, Y. B. (1988). Mesozoic evolution of the Lusitanian basin: Comparison with the adjacent margin. In G. Boillot, E. L. Winterer, & A. W. Meyer (Eds.), Proceedings of the Ocean Drilling Program Scientific Results (Vol. 103, pp. 757– 775). Ocean Drilling Program. https://doi.org/10.2973/odp.proc.sr.103.117.1988
Moreira, V. (1989). Seismicity of the Portuguese continental margin. In S. Gregersen, & P. Basham (Eds.), Earthquakes at North-Atlantic passive margins: Neotectonics and postglacial rebound (pp. 533– 545). Kluwer Academic Publishers. https://doi.org/10.1007/978-94-009-2311-9_31
Murray, J. R., Minson, S. E., & Svarc, J. L. (2014). Slip rates and spatially variable creep on faults of the northern San Andreas system inferred through Bayesian inversion of Global Positioning System data. Journal of Geophysical Research: Solid Earth, 119, 6023– 6047. https://doi.org/10.1002/2014JB010966
Ostman, G. M. B., Vilanova, S. P., Nemser, E. S., Falcao-Flor, A., Heleno, S. I. N., Ferreira, H. E., & Fonseca, J. F. B. D. (2012). Large Holocene earthquakes in the lower Tagus valley fault zone, Central Portugal. Seismological Research Letters, 83, 67– 76. https://doi.org/10.1785/gssrl.83.1.67
Palano, M., González, P. J., & Fernández, J. (2015). The diffuse plate boundary of Nubia and Iberia in the Western Mediterranean: Crustal deformation evidence for viscous coupling and fragmented lithosphere. Earth and Planetary Science Letters, 430, 439– 447. https://doi.org/10.1016/j.epsl.2015.08.040
Palano, M., Imprescia, P., Agnon, A., & Gresta, S. (2018). An improved evaluation of the seismic/geodetic deformation-rate ratio for the Zagros Fold-and-Thrust collisional belt. Geophysical Journal International, 213, 194– 209. https://doi.org/10.1093/gji/ggx524
Payne, S., McCaffrey, R., & King, R. W. (2008). Strain-rates and contemporary deformation in the Snake river plain and surrounding Basin and range from GPS and seismicity. Geology, 36(8), 647– 650. https://doi.org/10.1130/G25039A.1
Pereira, R., & Alves, T. M. (2013). Crustal deformation and submarine canyon incision in a Meso-Cenozoic first-order transfer zone (SW Iberia, North Atlantic Ocean. Tectonophysics, 601, 148– 162. https://doi.org/10.1016/j.tecto.2013.05.007
Pinheiro, L., Wilson, R., Pena dos Reis, R., Whitmarsh, R., & Ribeiro, A. (1996). The western Iberian margin: A geophysical and geological overview. In R. Whitmarsh, D. Daywer, A. Klaus, & D. Masson (Eds.), Proceedings of the Ocean Drilling Program, Leg 149, Scientific Results Volume (pp. 533– 545). IODP.
Ramalho, M., Matias, L., Neres, M., Carafa, M. M. C., Carvalho, A., & Costa, P. (2020). A sanity check for earthquake recurrence models used in PSHA of slow deforming regions: The case of SW Iberia. Natural Hazards and Earth Systems Science Discussions. https://doi.org/10.5194/nhess-2020-300
Rasmussen, E. ,S., Lomholt, S., Andersen, C., & Vejbæk, O. V. (1988). Aspects of the structural evolution of the Lusitanian Basin in Portugal and the shelf and slope area offshore Portugal. Tectonophysics, 300, 199– 225.
Reis, R., Pimentel, N., Fainstein, R., Reis, M., & Rasmussen, B. (2017). Influence of salt diapirism on the basin architecture and hydrocarbon prospects of the Western Iberian Margin. In J. Soto, J. Flinch, & G. Tari (Eds.), Permo-triassic Salt Provinces of Europe, North Africa and the Atlantic Margins. Elsevier. https://doi.org/10.1016/b978-0-12-809417-4.00015-x
Ribeiro, A., Cabral, J., Baptista, R., & Matias, L. (1996). Stress pattern in Portugal mainland and the adjacent Atlantic region, West Iberia. Tectonics, 15, 641– 659. https://doi.org/10.1029/95tc03683
Shen, Z.-K., Wang, M., Zeng, Y., & &Wang, F. (2015). Optimal interpolation of spatially discretized geodetic data. Bulletin of Seismological Society of America, 105(4), 2117– 2127. https://doi.org/10.1785/0120140247
Storchak, D. A., Harris, J., Brown, L., Lieser, K., Shumba, B., & Di Giacomo, D. (2020). Rebuild of the Bulletin of the International Seismological Centre (ISC)—Part 2: 1980–2010. Geoscience Letters, 7, 18. https://doi.org/10.1186/s40562-020-00164-6
Stucchi, M., Rovida, A., Gómez, A., Alexandre, P., Camelbeeck, T., Demircioglu, M., et al. (2013). The SHARE European earthquake catalogue (SHEEC) 1000–1899. Journal of Seismology, 17, 523– 544. https://doi.org/10.1007/s10950-012-9335-2
Sylvester, A. G. (1988). Strike-slip faults. GSA Bulletin, 100(11), 1666– 1703. https://doi.org/10.1130/0016-7606(1988)100<1666:ssf>2.3.co;2
Vilanova, S. P., & Fonseca, J. F. B. D. (2004). Seismic hazard impact of the Lower Tagus Valley Fault Zone (SW Iberia), Journal of Seismology, 8, 331– 345.
Vilanova, S. P., & Fonseca, J. F. B. D. (2007). Probabilistic seismic-hazard assessment for Portugal. Bulletin of the Seismological Society of America, 97, 1702– 1717. https://doi.org/10.1785/0120050198
Walker, D. J. (1982). Final report: Seismic interpretation for Petrogal concession areas 45, 46, 47/48. GPEP.
Wang, H., Wright, T. J., Liu-Zeng, J., & Peng, L. (2019). Strain-rate distribution in south-central Tibet from two decades of InSAR and GPS. Geophysical Research Letters, 46, 5170– 5179. https://doi.org/10.1029/2019GL081916
Wegmuller, U., Werner, C., Magnard, C., & Manconi, A. (2019). Co-seismic displacement vector retrieval for the Iran-Iraq Earthquake using Sentinel-1 (poster). ESA Living Planet Meeting Milano. Retrieved from https://www.gamma-rs.ch/uploads/media/2000-1_GAMMA_Software.pdf
Werner, C., Wegmuller, U., Strozzi, T., & Wiesman, A. (2000). GAMMA SAR and Interferometric Software, ERS - ENVISAT Symposium (pp. 16– 20). Gothenburg, Sweden, Retrieved from https://www.gamma-rs.ch/uploads/media/2000-1_GAMMA_Software.pdf
Wessel, P., & Smith, W. H. F. (1991). Free software helps map and display data. Eos Transactions American Geophysical Union, 72(41), 445– 441. https://doi.org/10.1029/90EO00319
Wilson, R. C. L., Hiscott, R. N., Willis, M. G., & Gradstein, P. M. (1989). The Lusitanian Basin of west-central Portugal: Mesozoic and Tertiary tectonic, stratigraphic and subsidence history. In A. J. Tankard, & H. R. Balkwill (Eds.), Extensional tectonics and stratigraphy of the North Atlantic margins (Vol. 46, pp. 341– 361). AAPG Memoir.
Woessner, J., Laurentiu, D., Giardini, D., Crowley, H., Cotton, F., Grünthal, G., et al. (2015). The 2013 European seismic hazard model: Key components and results. Bulletin of Earthquake Engineering, 13(12), 3553– 3596. https://doi.org/10.1007/s10518-015-9795-1
Youngs, R. R., & Coppersmith, K. J. (1985). Implications of fault slip rates and earthquake recurrence models to probabilistic seismic hazard estimates. Bulletin of the Seismological Society of America, 75(4), 939– 964.