GF - Comunicações em actas de encontros científicos internacionais
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- Assessing the degree of fracturing and weathered layer thickness using seismic and GPR dataPublication . Carvalho, João P. F.; Pinto, Carlos C.; Lisboa, Jose; Sardinha, Rui; Catrapona, Afonso; Borges, José Fernando; Tlemçani, M.
- Characterization of a concealed fault zone using P and S-wave seismic reflection dataPublication . Carvalho, João P. F.; Ghose, R.; Pinto, Carlos C.; Borges, José Fernando
- Developing a site-conditions map for seismic hazard assessment in PortugalPublication . Narciso, João; Vilanova, Susana; Lopes, Isabel; Oliveira, Carlos Sousa; Carvalho, João; Pinto, Carlos C.; Borges, José Fernando; Nemser, Eliza
- Earthquake mitigation in the Lisbon and Lower Tagus Valley area, PortugalPublication . Carvalho, João; Dias, Ruben Pereira; Pinto, Carlos C.; Cunha, Taigo A.; Leote, Jaime; Vilanova, Susana; Narciso, João; Borges, José Fernando; Ghose, Ranajit
- Earthquake mitigation in the Lisbon and Lower Tagus Valley area, PortugalPublication . Carvalho, João; Dias, Ruben Pereira; Pinto, Carlos C.; Cunha, Tiago A.; Leote, Jaime; Vilanova, Susana; Narciso, João; Borges, José Fernando; Ghose, Ranajit
- Estimation of imageable dip range of target structures in interferometric salt flank imaging with limited illuminationPublication . Loureiro, A.; Van der Neut, J.; Alves, Daniela; Carvalho, João; Afilhado, Alexandra; Draganov, D.; Matias, L.; Martins, T.
- GeoERA´s contribution towards resilience in Europe’s raw materials supply chainsPublication . Wittenberg, Antje; De Oliveira, Daniel Pipa Soares; González, Javier; Flindt Jørgensen, Lisbeth; Held, TomThe well-being of society and the interdependencies of national economies depend heavily on reliably functioning supply chains as the COVID-19 pandemic proved this long-known statement in everyone's daily life. None of the supply chains can do without the mostly mineral raw materials. The United Nations sees raw materials as the key component for achieving all 17 Sustainable Development Goals (SDGs).
- Heat Flow Density Estimations in the Portuguese Northern Hercynian Massif using Silica GeothermometryPublication . Correia, Antonio; Ramalho, ElsaABSTRACT: Surface heat flow density (HFD) estimates in the Portuguese northern Hercynian Massif are difficult to obtain using the usual Fourier method. As a matter of fact, this zone is mostly composed by granitoid and metamorphic rocks, and most wells drilled there are too shallow for reliable HFD calculations; furthermore, HFD estimates are scarce and their geographical distribution is still very irregular. All these conditions imply that a HFD map for this region must be obtained using alternative methods, such as the silica geothermometry method. Under certain conditions, the use of silica geothermometers to estimate HFD in mineral waters has proved to be an effective way to understand and establish the thermal regime in areas with scarce conventional HFD determinations. Because temperatures obtained with silica geothermometry are related to deep thermal conditions in the crust and to water-rock equilibrium, a regional HFD analysis may be carried out using those temperatures. The silica geothermometer, developed by Truesdell in 1976 (Truesdell, 1976), give good results for low SiO2 concentrations, which is the case for the Portuguese northern Hercynian Massif, and is applied to more than 30 samples of mineral water occurrences reported for the zone. This number of samples, even though small, is considerably higher and more evenly distributed than conventional HFD estimates for the same area. Application of silica geothermometry to northern Hercynian Massif waters shows a discrete reservoir temperature zoning, ranging from about 45 ºC, in its southwest limit, to more than 120 ºC, towards its northeast limit. Using temperatures obtained by silica geothermometry and heat flow density values calculated through the conventional method in an area of 1º x 1º in the study zone, an empirical linear relationship between HFD and temperatures obtained by silica geothermometry is obtained and used to construct a HFD map for the Portuguese northern Hercynian Massif. The resulting HFD map is compared with the general geological and structural framework, and an attempt to a geothermal characterisation of the Portuguese northern Hercynian Massif is made.
- Improving the knowledge on seismogenic sources in Lower Tagus Valley for seismic hazard purposesPublication . Carvalho, João; Pinto, Carlos C.; Costa, M.; Duarte, H.; Terrinha, Pedro; Rabeh, Taha; Borges, José Fernando; Dias, Ruben Pereira; Caldeira, Bento
- Improving the seismic hazard evaluation of the Lisbon and Lower Tagus Valley areaPublication . Carvalho, João P. F.; Pinto, Carlos C.; Costa, M.; Heleno, S.; Silva, M.; Rabeh, Taha; Cooksley, G.; Carrilho, F.The Lisbon and surrounding area of the Lower Tagus Valley has experienced in the past the effects of several moderate sized earthquakes that caused significant damage and destruction. They have been attributed to local sources, though in some cases the source remains to be located. The lack of outcrops in the flat lying Quaternary terrains, the low slip-rates of the area in connection with sedimentation and erosion rates that erase surface ruptures are among the causes of a poor association between faults and seismicty, which has opened way to geophysical studies. Seismic, potential-field and seismicity data have been recently used to improve the seismic hazard evaluation of the area. In this work we complement these studies with DTM and PSInSAR data with the purpose of obtaining an accurate evaluation of the seismic hazard of the study area. The correlation of improved epicentre locations with major fault zones located from the above mentioned data shows that we have progressed in the understanding of the earthquake sources in the region. Some structures show no apparent relationship with present-day seismicity but some are known to be active into the Quaternary. Further geophysical and geological studies are required to understand the causes.