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Publications

Publications by Rui Moura

2015

Multi-component joint analysis of surface waves

Authors
Dal Moro, G; Marques Moura, RMM; Moustafa, SSR;

Publication
JOURNAL OF APPLIED GEOPHYSICS

Abstract
Propagation of surface waves can occur with complex energy distribution amongst the various modes. It is shown that even simple Vs (shear-wave velocity) profiles can generate velocity spectra that, because of a complex mode excitation, can be quite difficult to interpret in terms of modal dispersion curves. In some cases, Rayleigh waves show relevant differences depending on the considered component (radial or vertical) and the kind of source (vertical impact or explosive). Contrary to several simplistic assumptions often proposed, it is shown, both via synthetic and field datasets, that the fundamental mode of Rayleigh waves can be almost completely absent. This sort of evidence demonstrates the importance of a multi-component analysis capable of providing the necessary elements to properly interpret the data and adequately constrain the subsurface model. It is purposely shown, also through the sole use of horizontal geophones, how it can be possible to efficiently and quickly acquire both Love and Rayleigh (radial-component) waves. The presented field dataset reports a case where Rayleigh waves (both their vertical and radial components) appear largely dominated by higher modes with little or no evidence of the fundamental mode. The joint inversion of the radial and vertical components of Rayleigh waves jointly with Love waves is performed by adopting a multi-objective inversion scheme based on the computation of synthetic seismograms for the three considered components and the minimization of the whole velocity spectra misfits (Full Velocity Spectra - FVS - inversion). Such a FVS multi-component joint inversion can better handle complex velocity spectra thus providing a more robust subsurface model not affected by erroneous velocity spectra interpretations and non-uniqueness of the solution.

2013

APPLICATION OF MULTICHANNEL ANALYSIS OF SURFACE WAVES (MASW) FOR SEISMIC HAZARD ASSESSMENT: A CASE STUDY IN THE CHONG-ALAY DISTRICT, KYRGYZ REPUBLIC

Authors
Moura, R; Umaraliev, R; Almeida, F; Abdrakhmatov, K; Nizamiev, A;

Publication
GEOCONFERENCE ON SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, SGEM 2013, VOL II

Abstract
The measurement of shear wave velocity (Vs) is an established approach in contributing to earthquake site response. In situ dispersive wave measurements are one of the ways of determining Vs to a certain depth. Rayleigh type measurements have had a significant development in the past two decades. Since Spectral Analysis of Surface Waves measurements appeared, in the late 80s and early 90s, other approaches have developed. The later Multichannel Analysis of Surface Waves method (MASW), that took advantage of the engineering seismograph and the increasing number software routines that became available, greatly enhanced the confidence of this type of in situ results towards assessing the shear wave velocity profile of the near surface. Thus within this work we aim to show the results of 27 dispersive wave tests, made for 48 educational facilities located in 20 villages of the Chong-Alay district, Osh oblast, Kyrgyz Republic. The results of these seismic tests contributed towards the micro seismic wider hazard assessment study we performed.

2014

Investigating Landfill Contamination by Visualizing Geophysical Data

Authors
Goncalves, V; Dias, P; Fontoura, MJ; Moura, R; Santos, BS;

Publication
IEEE COMPUTER GRAPHICS AND APPLICATIONS

Abstract
Geophysical experts aimed to establish a method to identify contamination by landfill leakage without chemically analyzing subsoil samples, which is time-consuming and expensive. To that end, researchers developed a software package that let the experts create 3D visualizations of geophysical data acquired around the landfill and apply statistical analysis to detect anomalous values. The data used, electrical resistivity, are typically sparse. So, the application employs kriging to interpolate the data and provide a volumetric representation of the subsoil resistivity. To avoid invalid conclusions, the visualization also represents uncertainty. The application enabled the experts to better understand the phenomenon and to develop and validate their method. Their evaluation of the application indicated that it helped them throughout the method's development and significantly eased their workload. © 2014 IEEE.

2013

Conceptualizing a mountain hydrogeologic system by using an integrated groundwater assessment (Serra da Estrela, Central Portugal): a review

Authors
Marques, JE; Marques, JM; Chamine, HI; Carreira, PM; Fonseca, PE; Monteiro Santos, FAM; Moura, R; Samper, J; Pisani, B; Teixeira, J; Carvalho, JM; Rocha, F; Borges, FS;

Publication
GEOSCIENCES JOURNAL

Abstract
Mountains are often considered as the world's water towers. This paper presents a critical review on the research concerning the integrated assessment of groundwater resources of the mountain hydrogeologic system of Serra da Estrela Natural Park (central Portugal). The study area is the Zzere river basin upstream of Manteigas village located at the Serra da Estrela Mountain in Central Portugal. It provides the source of strategic water resources for the Portuguese mainland, including normal groundwaters, thermomineral waters and surface waters. An integrated approach has been used to formulate a conceptual model for this complex mountain hydrogeological system by integrating the geological, morphotectonic, hydroclimatic, unsaturated soil zone, hydrogeological, hydrogeophysical, hydrogeochemical and isotopic data. This model has been useful to: i) evaluate the water resources; ii) provide the basis for a sustainable management of water resources, iii) design measures for groundwater exploitation and contamination control; and iv) set up land-use policies.

2023

MIFIRE- A PLANETARY GEOLOGY AND GEOPHYSICS RESEARCH PROJECT USING A SUBORBITAL MICROGRAVITY SPACEFLIGHT

Authors
Moura, R; Pires, AC; Martins, V; Marques, MC; Caldeira, A; Sá, I; MacHado, D;

Publication
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM

Abstract
The MiFiRE (Microgravity Fine Regolith Experiment) experiment, which will be launched this year on a suborbital space flight, currently scheduled for August 2023, was designed with the aim of better understanding the initial stages of planetary formation. The fundamental and embryonic question is to contribute to the study of how the mineral and rock particles, which do not have enough mass for the gravitational force to be influential, can then aggregate through electrostatic forces. In order to recreate the environment of deep space, it is assumed that the composition of meteorites that collide with the Earth, are mainly of silicate mineralogical composition or rich in metallic alloys (eg Fe-Ni). Therefore, in the experiment some fine material, identical to the lunar regolith (JSC-1), is used, in other words, amphiboles, pyroxenes, olivines and volcanic glass, along with two larger elements, a basalt cube and a metalic (siderite) meteorite cube (Octahedrite from Campo del Cielo, Argentina). It is intended that the particles be subjected to the microgravity environment and thus contribute to a better understanding of the general behaviour and the processes of preference of aggregation between the various components. This, in turn, contributes the characterization of the progressive development of planetesimals. This experiment was selected amongst 5 competing proposals in a contest launched by Massachusetts Institute of Technology's national representation, MIT Portugal, in 2020. © 2023 International Multidisciplinary Scientific Geoconference. All rights reserved.

2023

GENERAL CHARACTERISTICS OF THE CAPELINHOS VOLCANO (AZORES ISLANDS, PORTUGAL) AS A NEW PLANETARY ANALOG SITE AIMED AT SPACE EXPLORATION RESEARCH

Authors
Moura, R; Pires, AC; Pinto, MC; Nunes, JC;

Publication
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM

Abstract
Volcanic sites on Earth provide valuable insights into the geological processes that shape our planet and can also serve as effective analogs for studying similar volcanic activity on other celestial bodies, such as the Moon. This work aims to discuss the general characterization of the Capelinhos volcanic site, in the archipelago of Azores in Portugal, showing the potential as a planetary analog. It's barren landscape, covered with pyroclastic rocks can lend itself the purpose of becoming a lunar planetary analog site, possibly even a Martian site. This geological site was formed during an eruption that occurred in 1957-58, thus the vegetation is practically absent. By examining the physical and chemical properties of its pyroclastic rocks, as well as the associated volcanic landforms, researchers of different fields can better understand lunar volcanic activity and its implications for many aspects of future lunar exploration. Although its origin is different from most of the locations on the lunar surface, since it doesn't contemplate the impactism originated regolith characteristics and associated geomorphology, it does resemble this setting for a broad range of research objectives. © 2023 International Multidisciplinary Scientific Geoconference. All rights reserved.

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