João C. Nunes

• PhD
• Professor (Assistant) at University of the Azores

The main goal of the International Meeting "40 Years of the 1980 Azores Earthquake" was promoting a reflection of the earthquake of January 1 st , 1980, and the advances since them on topics like seismology, seismic hazard, and risk, building rehabilitation and public policies. Nevertheless, due to the COVID-19 outbreak, the organizing committee de...

“Ponta da Ferraria e Pico das Camarinhas” is a protected geosite in São Miguel Island in the Azores archipelago, Portugal. Due to its importance for the geoconservation strategy of the Azores UNESCO Global Geopark, monitoring actions of visitor impact were implemented in order to assure that the main geological features of this geosite continue to...

outreach paper - magazine Pingo de Lava

The stability of volcanic cavities particularly in urban areas and in touristic places presents high complex problems due to their nature, existing environment and mainly because the danger that represents for people and buildings, but also for the safeguard of those cavities as natural monuments. There are risk sources which might cause large dama...

The deterioration of concrete can be caused by different processes. Alkali-aggregate reactions are some of the most widely known modes of chemical deterioration, usually involving reactive forms of silica in the aggregates. The reaction produces an alkali-silica gel, which expands and creates a framework of cracks in the concrete. Samples of mafic...

Hydrogeologist EurGeol José Martins Carvalho (BSc, PhD, DSc) gave his last lecture at the School of Engineering of Polytechnic of Porto in January 2014, bringing to a formal close an outstanding career in multidisciplinary hydrogeology teaching and practice (in Europe, Africa, Middle-East, Asia, South America) and in applied research. Nowadays, he...

The geological heritage management should be integrated in spatial and environmental planning policies. In small islands (with less than 10 000 km² area and 500 000 inhabitants), the isolation, small size and anthropogenic pressures reduce the resilience of ecosystems and increase their vulnerability to global changes, requiring different integrate...

Após as celebrações do Ano Internacional do Planeta Terra - AIPT (2007-2009), foi formalmente criado, pela primeira vez em Portugal e sob a égide da Comissão Nacional da UNESCO, o Comité Nacional para o Programa Internacional de Geociências (IGCP- UNESCO), que é coordenado internacionalmente numa parceria entre a Organização das Nações Unidas da Ed...

Alkali-silica reactions have caused serious expansion and cracking in concrete structures worldwide. Volcanic rocks have been found to be potentially alkali-reactive in a number of countries such as Argentina, Iceland, Japan, New Zealand and Turkey. The Azorean rocks used as aggregates are mainly basalts and some trachytes. The characterization of...

Volcanic rocks have been found to be the cause of concrete deterioration in several countries (Argentina, Iceland, Japan, New Zealand and Turkey), due to the occurrence of alkali-silica reactions. Alkali-silica reaction (ASR) is a deterioration phenomenon that occurs between alkaline (Na+ and K+) and hydroxyl (OH-) ions in the cement and certain re...

Volcanic rocks have been found to be potentially alkali-reactive in a number of countries, including Japan, New Zealand, Iceland and Turkey. In order to characterize the potential reactivity of the volcanic rocks in Azores a project is being carried out, under the support of the Azores Government: the ReAVA Project – “Characterization of Potential...

The Azores Archipelago (a Portuguese Autonomous Region) is located in the North Atlantic at the distance of 1,815 km from the Mainland Portugal, and is formed by nine islands and several islets, which are dispersed along a strip with 600 km length and with a WNW-ESE trend.

The Caldeiras da Ribeira Grande (CRG) site is characterised by low-temperature fumaroles, boiling mudpools and gas ground-emissions, some of them artificially confined to a tank. Cooling and oxidation of deep hydrothermal fluids under boiling control the formation of acid condensates and strong hydrothermal alteration of the hosting volcanic rocks....

The Caldeiras da Ribeira Grande site is placed at the north-eastern side of the Ribeira Grande geothermal system (S. Miguel Island) and includes a fumarolic field with multiple discharge points, closely associated with a mud pool. The major discharge is artificially confined to a tank, also fed by a cold (≈19 °C) spring water, allowing the accumul...

Las cuevas de Algar do Carvão (una sima volcánica de génesis compleja) y Branca Opala (un tubo volcánico) se diferencian de otras cuevas de la isla de Terceira por tener espeleotemas formados sólo por ópalo. Esta composición, y el hecho de ser cuevas volcánicas, hacen pensar que el origen de la sílice pueda estar ligado a la actividad hidrotermal....

The Azores archipelago, with a peculiar geodynamic setting, presents a huge geodiversity and important geological heritage, being considered a natural laboratory of volcanic geodiversity. In the last decade, the geodiversity and geological heritage of the Azores archipelago is being inventoried, characterized, quantified, protected and promoted. No...

We present new He isotopic data from subaerial and submarine samples collected along the Terceira Rift (Azores Plateau) in order to constrain the sources involved in the Azores magmatism in the unique geodynamic context of the Azores triple junction. Lower than MORB 4He/3He isotopic ratios were determined on olivines from the Terceira Island and th...

Caldeiras da Ribeira Grande fumarolic field is located in the Fogo Volcano complex, São Miguel Island (Azores Archipelago, Portugal). These are associated to a geothermal system of high enthalpy that allows the existence of singular thermal muds or peloids that are continuously mixed with water inside a manmade pool. The peloids produced by the mat...

The detailed geological mapping of the Basaltic Fissural Zone in the central area of Terceira Island, the field stratigraphical relationships observed and published and new isotopic ages now provided allowed to correlate the 26 volcanic caves existing in the mapped area (between Pico da Bagacina area and the north coast) with the correlated volcani...

The Azores archipelago, located in the North Atlantic Ocean, is formed by nine islands, several islets and the surrounding seafloor. Despite the small terrestrial area of the archipelago (2332 sq. km), the Azores geodiversity represents elements closely linked to the dynamics of planet Earth, in particular, the volcanism and geotectonic of this reg...

After the celebrations of the International Year of Planet Earth-IYPE (2007-2009), the Portuguese National Committee for the International Geosciences Programme (IGCP) of UNESCO was formally established in Portugal, for the first time, under the aegis of the Portuguese National Commission for UNESCO. This Programme is based in a partnership between...

In recent years several studies essentially developed under two Projects PPERCAS and USuET led to the assemblage of an earthquake simulator e-Risk capable to com-pute earthquake losses for a stock of buildings and a group of lifelines, given a source and a magnitude. e-Risk is composed by several modules from wave attenuation, soil influence, struc...

The Azores archipelago is distinguished by its unique natural beauty and marine setting. Thanks to its volcanic origin, the region has a very rich and remarkable geodiversity that includes a diversity of landscapes with innumerable craters, volcanic lakes, fumaroles, hot springs, volcanic caves, marine fossil deposits and thermal water springs. The...

The conservation of the geological heritage requires the support of appropriate policies, which should be the result of the integration of nature conservation, environmental and land-use planning, and environmental education perspectives. There are several papers about inventory methodologies for geological heritage and its scientific, educational...

The conservation and management of the geological heritage requires the support of appropriate policies, which should be the result of the integration of nature conservation, environmental and land-use planning, and environmental education perspectives. It is necessary to establish protocols and mechanisms for the conservation and management of geo...

One of the tasks of the European Project UPStrat-MAFA (Urban Prevention Strategies using MAcroseimic Fields and FAult Sources) is to develop an educational system aimed at long-term training, mainly on seismic hazard and risk. This task will be carried out by sharing the expertise of partners of the project to set different actions, encompassing pr...

A mobile earthquake interactive path is an action of disaster-risk reduction given by long-term activities based on an educational information system. The idea is to provide a realistic space and to design in it an interactive path, aimed at both children and adults, explaining. issues related to seismic hazard especially in urban sectors close to...

Earthquake damage includes non-structural failure, failure of utility systems and, infrastructure, loss of function and other non-structural damage. Occupants, building owners, insurance companies, building inspectors and others, through their use of the buildings, systems and content, can affect the risk of such negative events. Thus, a prerequisi...

This contribution presents the general framework of the European project UPStrat-MAFA "Urban disaster Prevention Strategies using MAcroseismic Fields and FAult Sources" and its ongoing activities. A unique probabilistic procedure is being used for seismic hazard evaluation, using both macroseismic fields and characteristics of fault sources for the...

Volcanic rocks have been found to be potentially alkali-reactive in a number of countries, including Japan, Iceland and Turkey. To characterize the potential reactivity of the volcanic rocks used as aggregates for concrete in the Azores islands, an experimental program is being carried out which includes petrographic examination, chemical analysis...

Borges P.A.V., Cardoso P., Amorim I.R., Pereira F., Constancia J.P., Nunes J.C., Barcelos P., Costa P., Gabriel R. and Dapkevicius M.d.L. 2012. Volcanic caves: priorities for conserving the Azorean endemic troglobiont species. International Journal of Speleology, 41(1), 101-112. Tampa, FL (USA). ISSN 0392-6672. DOI: http://dx.doi.org/10.5038/1827-8...

The Ferraria thermal water emerges at the sea level in the Ferraria lava delta (western edge of S. Miguel Island, Azores) with temperature of ca. 60°C and pH varying between 5.4 and 6.2. It is of sodium chloride type, resulting from ca. 50% seawater mixing with an acid brackish, at ≈100°C, denoting the presence of significant CO2(g) and the progres...

Universidade dos Açores, Dep. Geociências, jcnunes@notes.uac.pt Associação "Os Montanheiros", Angra do Heroísmo, Açores The Branca Opala cave (length 99m, maximum width 5 m, maximum height 10m) was developed in a lava tube on Terceira Island (Azores) (Fig. 1). The island harbours four polygenetic volcanoes (Pico Alto, Santa Bárbara, Guilherme Moniz...

Universidade dos Açores, Dep. Geociências, jcnunes@notes.uac.pt Associação "Os Montanheiros", Angra do Heroísmo, Açores The Branca Opala cave (length 99m, maximum width 5 m, maximum height 10m) was developed in a lava tube on Terceira Island (Azores) (Fig. 1). The island harbours four polygenetic volcanoes (Pico Alto, Santa Bárbara, Guilherme Moniz...

The Azores archipelago is located at the North America, Eurasia and Africa triple junction and shows seismicity and volcanism typical of an active plate boundary. Terceira Island has been affected by several damaging earthquakes being the 1980 January 1st event (M=7.2) the strongest in Azores during the last century.São Sebastião volcanic crater, a...

Noble gas data (He and Ne) on olivine phenocrysts obtained from Azores' lavas sampled along the Terceira Rift will be presented in this work. The Terceira Rift is considered as one of the slowest spreading system in the world (Vogt & Jung, 2004). Lava samples were collected inland at S. Miguel, Terceira, Graciosa, Pico and Faial Islands as well at...

A continuous-flow GC/IRMS technique has been developed to analyse delta(15)N values for molecular nitrogen in gas samples. This method provides reliable results with accuracy better than 0.15 per thousand and reproducibility (1sigma) within+/-0.1 per thousand for volumes of N(2) between 1.35 (about 56 nmol) and 48.9 muL (about 2 mumol). The method...

In Portugal, the presence of high temperature geothermal resources is restricted to the volcanic islands of the Azores, which are associated with the triple junction of the North American, Eurasian and African plates. New investment projects at the Ribeira Grande geothermal field on the island of São Miguel, implemented by SOGEO (Sociedade Geotérmi...

Terceira Island, together with Graciosa, São Jorge, Pico and Faial islands form the Central Group of the Azores Archipelago. Located in the Terceira Rift, this island shows an active volcanism (with a wide variety of rocks compositions and structures) and an important seismic activity. From east to west, Terceira Island includes four central polyge...

We present some improvements of a gravity inversion method to determine the geometry of the anomalous bodies for priori density contrasts. The 3-D method is based on an exploratory process applied, not for the global model, but for the steps of a growth approach. The (positive and/or negative) anomalous structure is described by successive aggregat...

"GEOAVALIA Project" main goal is to gather and join all relevant information related with the exploitation zones (e.g. quarries) in the Azores Islands, promoting an inventory of these sites all over the Archipelago. That inventory, includes a database supported on a GIS System, where a detailed characterization of these sites was done, focusing on...

A representative set of 30 lakes from the Azores archipelago (Portugal) has been studied to obtain data on their volcanic setting and water geochemistry. The majority of the studied lakes are located inside volcanic craters and subsidence calderas, while the remaining lakes are located in topographic depressions not associated with volcanic centres...

Pico Island is the youngest (< 300 ka) island of the Azores archipelago, dominated on its western sector by the stratovolcano of Pico Mountain, which rises about 3.5 km above the surrounding ocean floor. The other two major morpho-tectonic units of the island include the shield volcano of Topo, and the “Achada Plateau,” a 29 km long volcanic ridge,...

El vulcanismo de la isla do Corvo (Azores Occidentales, Portugal) comprende diversos episodios eruptivos, desde 1.5 a 1.0 Ma. Los líquidos son mayoritariamente basaltos con una composición modal de olivino, Ti-augita, plagioclasa y Ti-magnetita, existiendo una variedad de litotipos petrográficos según la proporción modal de las fases mayoritarias....

Do ponto de vista morfo-vulcânico, a ilha do Pico compreende três zonas distintas: 1) um imponente estratovulcão que domina todo o sector ocidental da ilha, a Montanha do Pico; 2) um segundo edifício vulcânico central, do tipo vulcão em escudo, o vulcão do Topo e 3) uma extensa cordilheira vulcânica com 29 km de comprimento e orientação geral WNW-E...

RESUMO A Directiva do Parlamento Europeu e do Conselho nº 2000/60/CE, de 22 de Dezembro, denominada Directiva Quadro da Água (DQA) constitui, reconhecidamente, o mais importante instrumento integrador da política da Água da União Europeia. Um dos aspectos inovadores deste diploma foi a introdução do conceito de "estado ecológico" para a avaliação d...

The Azorean archipelago is composed of nine volcanic islands located in the North Atlantic Ocean, in the the biogeographic macaronesia region (that also includes Madeira Canarias and Cape Verde archipelagos), between 36º 45´and 39º 43´ latitude North and 24º 45´and 31º 17´longitude West. The islands have a total surface area of 2,352 km2 and are sp...

PRÓLOGO Em face das suas peculiares características geológicas, em sentido lato, o arquipélago dos Açores constitui um autêntico laboratório natural para uma diversidade de estudos na área da vulcanologia, ciência marcadamente multidisciplinar, o que lhe confere um estatuto de relevante interesse para muitos profissionais. O presente trabalho visa...

Surveying around volcanic ocean islands with sonars has recovered important information on giant landslides, faults and primary volcanic features, but efforts so far have largely been unable to image shallow water coastal areas because of vessel safety. Here we report surveying with a Reson 8160 multibeam sonar aboard a shallow draft research vesse...

10. Mitchell N.C., Schmitt T., Isidro E., Tempera E., Cardigos F., Nunes J.C., Figueiredo J. (2004). Multibeam sonar survey of the central Azores volcanic islands. InteRidge News, 12(2), pp. 30-32.

The seismic response of the São Sebastião volcanic crater, located at the SE end of Terceira Island (Azores), is characterized by an amplification of ground movements inside the crater with respect to the surrounding area. This variability of ground motion is also observed inside the volcanic depression itself. To gain insight into this phenomenon,...

1) (1) Azores University. (2) Volcanologic Observatory of the Azores (2) Zfranca@notes.uac.pt The Azores Archipelago is located at the North Atlantic and is formed by nine islands where seven occupied a platform surrounded by the American Plate (AM), at west (Fig. 1), the African Plate (AF), at south and the Eurasian Plate (EU) at northeast. The Mi...

RESUMO No presente trabalho apresenta-se uma primeira reavaliação da casualidade sísmica das ilhas do Grupo Central do Arquipélago dos Açores, com o objectivo de se estabelecer um zonamento actualizado e mais detalhado para o Arquipélago. Este estudo foi efectuado com base na compilação de catálogos sísmicos históricos e instrumentais da região dos...

Probabilistic seismic hazards maps have been prepared either for the archipelago of the Azores in general terms, or for the islands of the Central Group using updated seismic information for the region, including a revision of the earthquake catalogue for the period 1522-1998. Two different approaches were used: (i) a standard seismic source model...

The Azores Islands are located in the mid-Atlantic region near the triple junction where the Euro-Asiatic-African-American plates join together. Seismic activity in the area is very high, as can be observed either from historical events since the fifteenth century, from present day microseismicity, and from direct and indirect measurements of recen...

Nowadays the Natural Heritage of The Azores Islands is being considered not only by its flora and fauna (especially by the endemic and indigenous species - e.g. its biodiversity), but also by the geological formations that support and constrain them. In fact, the Azorean biotic world, including the Azorean Man, "has roots" on the volcanoes that bui...

INTRODUÇÃO As ilhas dos Açores apresentam uma grande variedade de rochas, formas, estruturas e paisagens, que derivam, entre outros factores, da natureza dos magmas, do tipo de vulcanismo, dos condicionalismos geotectónicos intrínsecos à sua génese e em especial do seu posicionamento no Atlântico Norte, na junção tripla das placas litosféricas Euro...

Resumo A rica geodiversidade vulcânica do arquipélago dos Açores e o valor dos geossítios que o integram, justificam a constituição de um Geoparque nesta região autónoma, objectivo estratégico assumido pelo Governo Regional dos Açores. O "Geoparque Açores" deverá afirmar-se como um território que combina a protecção e a promoção do seu património g...

RESUMO Em publicação anterior (Nunes, 2002) deu-se conta dos trabalhos de tipificação, caracterização e levantamento do parque habitacional da vila das Lajes do Pico, direccionados para o estabelecimento de cartas de vulnerabilidades da zona compreendida entre o edifício sede do município das Lajes e a zona do Castelete. Na sequência de trabalhos d...

We present the first nitrogen isotope data from hydrothermal fluids of Graciosa, Terceira and S. Miguel Islands (Azores, Portugal), together with helium isotope composition. 15N values are slightly enriched in light isotopes (from -0.7‰ to -2.2‰) with respect to air, while 3He/4He ratios range from 5 to 6 Ra in Sao Miguel island and from 8 to 9.1...