73 documents found, page 1 of 8
Soil Classification Maps for the Lower Tagus Valley Area, Portugal, Using Seism...
Carvalho, João; Dias, Ruben; Borges, José Fernando; Quental, Lídia; Caldeira, BentoABSTRACT: The Lower Tagus Valley (LTV) region has the highest population density in Portugal, with over 3.7 million people living in the region. It has been struck in the past by several historical earthquakes, which caused significant economic and human losses. For a proper seismic hazard evaluation, the area needs detailed V-s30 and soil classification maps. Previously available maps are based on proxies, or ...
Reappraisal of active tectonics of the Porto Alto buried fault zone (Portugal) ...
Carvalho, João; Cabral, João; Ghose, Ranajit; Borges, José Fernando; Dias, RubenABSTRACT: The Lower Tagus Valley area (LTV), where Lisbon is located, has been affected by several destructive, M 6+ earthquakes whose sources remain to be determined. The identification of expectable surface or near surface ruptures in the area is a challenging task that requires a multidisciplinary analysis that includes geophysical techniques, as the source faults are mainly buried despite likely to deform U...
Unconventional Three-Dimensional Active Seismic Tomography Applied in the Lousa...
Hamak, Ines; Teixeira, Pedro; Borges, José Fernando; Koulakov, Ivan; Oliveira, Rui Jorge; Caldeira, Bento; Bezzeghoud, Mourad; Xavier Matos, João ManuelABSTRACT: The Lousal Mine (Iberian Pyrite Belt, Portugal) was operated from 1900 to 1988 for the extraction of massive sulphides and was later rehabilitated as a science museum. It was selected as a test site for underground muon tomography applied to geophysical surveys, as part of the LouMu project. This study focuses on seismic tomography to analyse the subsurface above the mine gallery, primarily surveyed b...
Advanced Geophysical Processing of Ground-Penetrating Radar and Magnetic Datasets
Oliveira, Rui Jorge; Caldeira, Bento; Teixidó, Teresa; Borges, José FernandoDue to the presence of an excessive amount of noise in the data, archeological geophysics frequently produces results that cannot be used to evaluate the content that may exist in the subsurface. If it is impossible to differentiate between signal and noise, excessive noise will result. Its genesis, when it is attributable to heterogeneities in the ground (overthrows, corners) that produce as many reflections a...
Optical study of soil samples contaminated by heavy metals from the São Domingo...
Oliveira, Rui Jorge; Teixeira, Pedro; Caldeira, Bento; Borges, José Fernando; Costa, Maria João; Bortoli, Daniele; Potes, Miguel; Rodrigues, GonçaloThe study of soils contaminated by heavy metals (HMs) is a hard task that implies the collecting of soil samples in an area representative of the contaminated space. For example, for water samples, the law requires the creation of a study grid with 5 ha spacing. Considering this spacing requirement, to the soil from the São Domingos Mine, that have an area of approximately 2000 ha, we need to collect 400 sample...
Livro de Resumos da 11ª Assembleia Luso Espanhola de Geodesia e Geofísica
Caldeira, Bento; Bortoli, Daniele; Duarte, Ediclê; Buforn, Elisa; Carrilho, Fernando; Couto, Flávio; Ribeiro, Helena; Sobrino, José AntónioLivro de Resumos da 11ª Assembleia Luso Espanhola de Geodesia e Geofísica
Depth estimation of pre-Kalahari basement in Southern Angola using seismic nois...
Carvalho, João; Alves, Daniela; Borges, José Fernando; Caldeira, Bento; Cordeiro, Domingos; Machadinho, Ana; Oliveira, Álvaro; Ramalho, ElsaABSTRACT: The remote Southern region of Angola is covered by siliciclastic Kalahari Cenozoic formations that host underground aquifers of great importance to local populations affected by water scarcity problems. These aquifers are well developed where Kalahari sands reach appropriate thicknesses. On the other hand, at the eastern end of this area, regional aeromagnetic data recently acquired suggested the poss...
Muon tomography with Resistive Plate Chambers for geological characterization
Sarmento, Raul; Castro, Alberto Blanco; Caldeira, Bento; Tomé, Bernardo; Loureiro, Custódio; Clemêncio, Filomena; Alexandre, Isabel; Costa, JoãoABSTRACT: Muon tomography is one of several fields of applied physics that have witnessed the successful use of particle detection based on Resistive Plate Chambers (RPC). In this work, we report on an innovative project concerning transmission muography for geological characterization. For this purpose, a muon telescope built of four RPC planes was mounted on an adjustable structure and the telescope's respons...
Studying the water supply system of the Roman villa of Pisões (Beja, Portugal) ...
Carneiro, André; Oliveira, Rui Jorge; Trapero Fernandez, Pedro; Caldeira, Bento; Borges, José FernandoThe Roman villa of Pisões (Beja, Portugal) was part of the Lusitanian colony of Pax Iulia. This place stands out for the predominance of the water element in several structures of the villa, highlighting the balneum and the large natatio, one of the largest known in Roman Hispania. The records of the initial excavations that took place beginning in 1967 do not allow the establishment of clear functionalities of...
Using advanced geophysical data processing to improve low detection data in arc...
Oliveira, Rui Jorge; Caldeira, Bento; Borges, José Fernando; Bezzeghoud, MouradGeophysical data with noise issues are quite common, resulting in low detection conditions. This prevents the ground content from being evaluated to determine the existence of structures buried in the ground in an archaeological site. Standard processing on ground-penetrating radar and magnetic data does not effectively eliminate or mitigate this effect. The use of advanced and customized data processing is a v...