Pedro Terrinha

Instituto Português do Mar e da Atmosfera | IPMA · Divisão de Geologia e Georecursos Marinhos

The crustal and uppermost lithospheric mantle of the São Miguel Island in the Azores Plateau was investigated using one 160 km long refraction and wide angle reflection seismic profile across the island and the Terceira Rift along with multichannel seismic reflection profiles on the top of it. P-wave velocity model shows that São Miguel Island is m...

The Sines Contourite Drift (SCD) in the Alentejo Margin (southwest Iberia margin) is a middle-slope plastered drift mainly comprising hemipelagic and muddy contourite sediments, which is affected by many landslide scars on both steep and gentle slopes. This work presents geotechnical analysis results for the Late Pleistocene–Holocene sediments of t...

The Iberian Peninsula is surrounded to the north by the convergence margin between Eurasia and the former Iberian plates (North and Northwest Iberian margin), and to the south by a transform plate boundary between Eurasia and Nubia (Gulf of Cádiz) to a shear-compressive indentation of Nubia northwards in the Alborán Sea. These margins are affected...

We present pore-fluid geochemistry and heat-flow data along the SWIM1 fault in the Horseshoe Abyssal Plain (northeastern Atlantic Ocean). The SWIM1 fault is part of the transcurrent plate boundary between Africa and Eurasia and cuts through as much as 5-km-thick sediments overlying >140 Ma oceanic lithosphere. In a number of places, restraining seg...

Submarine landslides are a ubiquitous geohazard in the marine environment and occur at multiple scales. Increasing efforts have been made during the last decade to catalogue and categorise submarine landslides in comprehensive databases, aiming to better understand their preconditioning and trigger factors. Using the recently compiled, open-access...

Submarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Efforts have recently been made to compile databases of submarine landslide distribution a...

The Earth’s surface is constantly being recycled by plate tectonics. Subduction of oceanic lithosphere and delamination of continental lithosphere constitute the two most important mechanisms by which the Earth’s lithosphere is recycled into the mantle. Delamination or detachment in continental regions typically occurs below mountain belts due to a...

The aim of this work is to make a synthesis at regional scale focused on the geophysical characterization of submarine faults around the Iberian margin to identify active structures and analyze their development in the framework of the present plate organization. Most of these submarine faults show seabed morphological expressions mapped with high-...

Seamounts are spectacular bathymetric features common within volcanic and tectonically active continental margins. During their lifecycles, they evolve through stages of construction and destruction. The latter are marked by variable magnitude flank collapses that often interrupt the evolution of seamounts and constitute a major source of hazard. T...

Submarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Efforts have recently been made to compile databases of submarine landslide distribution a...

Cruise No. M162 06.03.2020 – 11.04.2020 Ponta Delgada (Portugal) – Emden (Germany) GLORIA-FLOW

The Sines Contourite Depositional System, located in the Southwest Portuguese Margin, is a central segment of the Iberian Contourite Depositional Complex, built under the influence of the Mediterranean Outflow Water (MOW). This work presents the onset and evolution of this system using multibeam bathymetry, multichannel seismic reflection lines, se...

Outer shelf sedimentary records are promising for determining the recurrence intervals of tsunamis. However, compared to onshore deposits, offshore deposits are more difficult to access, and so far, studies of outer shelf tsunami deposits are scarce. Here, an example of studying these deposits is presented to infer implications for tsunami-related...

The Sines Contourite Drift (SCD), located in the Alentejo margin, southwest Iberian continental margin, has been through many depositional phases in result of climatic variations and bottom current oscillations, which determined a variable depositional pattern and an irregular sedimentary evolution since the Late Pleistocene. The SCD, being in the...

This paper synthesizes the geology of the Atlantic Margin off the coast of Iberia and surrounding Abyssal Plains using published thematic mapping freely downloadable from EMODNET-Geology portal at different scales. Selected information was chosen in order to highlight mineral occurrences and natural hazards overlaid on geological and morphological...

Coastal erosion impact on low-lying sandy shorelines represents a worldwide problem, which is particularly felt in various segments of the Portuguese coast where this geomorphological type represents 42% of its total length. Beach nourishment is a viable engineering alternative for shore protection and the assessment of offshore sources of beach-fi...

The SW Iberian margin is an oblique passive margin developed during the Mesozoic, as part of the opening of the westernmost Ligurian Tethys. The Algarve Basin developed on the SW Iberian margin and its sedimentary record was strongly controlled by tectonics. The Algarve Basin was dominated during the Mesozoic by WSW–ENE trending extensional faults...

Artificial nourishment of sandy beaches using sediment from borrow areas located on the continental shelf is increasingly a recommended solution for reversing the erosion process that affects the coastal zone. However, the impact of sand extraction in the shelf and deposition on the beach on the benthic communities (structure and functioning) is st...

Submarine landslides are common features occurring on the flanks of seamounts. Often triggered by earthquakes or volcanic activity, such landslides are potential generators of tsunamis that constitute a dire geohazard for coastal communities. Understanding the recurrence history and geomorphology of seamount-flanking landslides and their link to se...

Resumo O projeto "Caracterização do impacte da extração de areias e avaliação da taxa de recuperação do ecossistema-ECOEXA" tem por objetivo estudar o impacto associado à extração de areia em manchas de empréstimo de sedimento, destinadas à alimentação artificial de praias, na integridade do fundo marinho. A monitorização servirá para estudar a evo...

The stratigraphy of the Tagus river ebb-tidal delta off Lisbon (Portugal) is investigated using high resolution multichannel seismic reflection profiles with the purpose of searching for sedimentary or erosive features associated with landslides. The Tagus delta is sub-divided in two prograding seismic units of 17 ky to 13 ky and 13 ky to Present b...

A global view of the Mesozoic-Cenozoic geodynamic evolution of the Iberian microplate is necessary to determine the role of inherited Variscan structures in the configuration of the Alpine Cycle. Furthermore, it is important to reconstruct the extensional Mesozoic geometries of the Iberian margins, presently inverted during the Cenozoic compression...

The Alpine orogeny is well recorded onshore and offshore by tectonic inversion of the Mesozoic rift basins. Large scale linear seamounts (more than 250 km long and with up to 5 km of uplift) involving oceanic and continental lithosphere were carried on top of thrusts, such as the Gorringe seamount and the Estremadura Spur in the SouthWest and West...

The West and SouthWest Margins of Iberia started their formation as intra-continental rifts during initial break up of Pangea in Triassic times. The tectono-stratigraphic record of the Algarve, Alentejo and Lusitanian basins and their offshore prolongation documents the syn-rift, post-rift and passive margin phases of the rifting process as well as...

A Agência Portuguesa do Ambiente, I.P., enquanto entidade gestora do litoral, desenvolveu o projeto CHIMERA com o objetivo de realizar trabalhos de reconhecimento sedimentar, morfológico e de caraterização físico-química de potenciais manchas de empréstimo na plataforma continental. Apresenta-se sumariamente os resultados obtidos, os quais são fund...

The CHIMERA project, contracted by the Portuguese Environment Agency (APA) and co-funded by the European Union Cohesion Fund (Portugal 2020 | POSEUR) intended to characterize the sedimentary record of three 10 km2 areas and one 5 km2 area in the Portuguese inner shelf. Multibeam bathymetry and backscatter, parametric echo-sounder, ultra-high resolu...

Marine transform faults and associated fracture zones (MTFFZs) cover vast stretches of the ocean floor, where they play a key role in plate tectonics, accommodating the lateral movement of tectonic plates and allowing connections between ridges and trenches. Together with the continental counterparts of MTFFZs, these structures also pose a risk to...

An integrated analysis of multibeam bathymetry and single- and multichannel seismic records were used to image the morpho-stratigraphy of the Alentejo Margin (Southwest Portuguese Continental Margin). The complex interaction of several alongslope and downslope processes in the area leads to the formation of various bottom current driven depositiona...

On the 1st of November 1755, a giant 8.7 magnitude earthquake struck off the coast of Portugal, destroying the city of Lisbon. The seismic event and the following tsunami triggered the interest of philosophers and contributed to the development of modern seismology. In 1969, a 7.9 magnitude earthquake struck in the same region. This was the time wh...

The CHIMERA project, contracted by the Portuguese Environment Agency (APA) and co-funded by the European Union Cohesion Fund (Portugal 2020 | POSEUR) intended to characterize the sedimentary record of three 10 km2 areas and one 5 km2 area in the Portuguese inner shelf. Multibeam bathymetry and backscatter, parametric echo-sounder, ultra-high resolu...

In this study, we present a new estimation of the gravitational potential energy (GPE) in Iberia and use numerical modeling to evaluate its relative contribution to the present-day stress field and deformation. We also present an improved (larger time span and denser coverage) compilation of Global Navigation Satellite System velocities, which we u...

A GIS catalogue of gas seeps around the Iberian Margin has been performed for the first time in the framework of the EMODNET-Geology-3 European project. Gas seep-related features include mud volcanoes and pockmarks but also other indicators of seabed fluid venting as the occurrence of methane-derived authigenic carbonates (MDACs) and chemosynthetic...

A prominent positive gravimetric and magnetic anomaly stands out in the region of the Guadalquivir-Portimão Banks, Gulf of Cadiz, off SW Iberia. The bathymetric and gravimetric highs have been interpreted as resulting from basement uplift occurred during Mesozoic rifting followed by overthrusting during the Alpine orogeny. However, we show that bas...

In Mesozoic times, the SW Iberian margin was a passive margin lying to the northeast of the triple junction of the Ligurian Tethys, Central Atlantic and Northern Atlantic. Seismic interpretation and gravity modelling shows the possible presence of Ligurian Tethys oceanic crust under the Gulf of Cadiz and the existence of anomalous density bodies at...

The geometry and emplacement of the ~ 96 km², Late Cretaceous Sintra Igneous complex (SIC, ca. 80 Ma) into the West Iberian passive margin is presented, based on structural data, gravimetric modeling, and magnetic fabrics. A granite laccolith (~ 76 km², < 1 km thick, according to gravimetric modeling) surrounds a suite of gabbro–diorite–syenite plu...

Studies that focus on meiofaunal assemblages of deep-sea mud volcanoes show an unpredictable abundance and diversity in a clear response to the different environmental conditions of the seeped sediment. The mud volcanoes Abzu, Tiamat and M. Ivanov (ATI), are located along the SWIM1 fracture zone, in front of the accretionary wedge of the Gulf of Ca...

The SW Iberian margin developed as a passive margin during Mesozoic times and was later inverted during the mainly Cenozoic Alpine orogeny. The initial syn-rift deposits include a Lower Jurassic evaporite unit of variable thickness. In the onshore, this unit is observed to thicken basinward (i.e., southward), in fault-controlled depocenters, and sa...

The Gulf of Cadiz seismicity is characterized by persistent low to intermediate magnitude earthquakes, occasionally punctuated by high magnitude events such as the M ~ 8.7 1755 Great Lisbon earthquake and the M = 7.9 event of February 28th, 1969. Micro-seismicity was recorded during 11 months by a temporary network of 25 ocean bottom seismometers (...

More than 300 nautical miles of multichannel seismic reflection data were acquired in the scope of the ASTARTE project (Assessment Strategy and Risk Reduction for Tsunamis in Europe), off Quarteira, Algarve, South Portugal. The main goal of this very high resolution multichannel seismic survey was to obtain high-resolution images of the sedimentary...

At present, the SW Iberian margin is located along the convergent Iberia-Nubia plate boundary. In Mesozoic times, the margin was located at the triple junction of the Ligurian Tethys, Central Atlantic and Northern Atlantic. The characterization of its crustal structure has allowed us to propose a configuration for this triple junction and to determ...

The oceanic crustal and uppermost lithospheric mantle structure across the Gloria Fault transcurrent plate boundary between Africa and Eurasia in the Northeast Atlantic is investigated based on seismic reflection, seismic refraction and wide angle reflection data. This experiment used 18 ocean bottom stations along a N-S 150 km long traverse togeth...

The SW of Iberia is currently undergoing compression related to the convergence between Nubia and Iberia. Multiple compressive structures, and their related seismic activity, have been documented along the diffuse Nubia-Iberia plate boundary, including the Gorringe bank west of the Gulf of Cadiz, and the Betic-Rif orogen to the east. Despite seismi...

Located on the West Iberian margin, between Cabo Carvoeiro and Cabo da Roca, the Estremadura Spur is a trapezoidal promontory elongated in an east-west direction, extending until the Tore seamount. Recently a field with more than 70 pockmarks was discovered in the NW region of the Estremadura Spur outer shelf (Lourinhã Monocline). Pockmarks are the...

EU project ASTARTE aims at developing a higher level of tsunami hazard assessment in the North East Atlantic, Mediterranean and Connected seas (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative work of 26 institutes from 16 countries and links together the desc...

This study presents the preliminary results of MINEPLAT survey, organised by Universidade de Évora in partnership with Instituto Português do Mar e da Atmosfera). It is based on the analysis of geophysical data collected during that survey: ultra-high resolution seismic data, multibeam data (both bathymetry and backscatter data) and magnetic data....

European Multidisciplinary seafloor and the Observatory of the water column for Development (EMSODEV) is a Horizon-2020 UE project whose overall objective is the operationalization of eleven marine observatories and four test sites distributed throughout Europe, from the Arctic to the Atlantic, from the Mediterranean to the Black Sea. The whole inf...

EMSO (European Multidisciplinary Seafloor and water-column Observatory, www.emso-eu.org) is a large‐scale European Research Infrastructure I. It is a distributed infrastructure of strategically placed, deep‐sea seafloor and water column observatory nodes with the essential scientific objective of real‐time, long‐term observation of environmental pr...

We propose a new explanation for the origin of the historical and instrumental very high magnitude (Mw > 8.5) earthquakes offshore SW Iberia (NE Atlantic). We investigate the occurrence of thrust-wrench tectonic interference and stress transfer between two major active oceanic faults as a possible cause for: a) successive (cascading) seismic multir...

We present an improved neotectonic numerical model of the complex NW Africa – SW Eurasia plate boundary segment that runs from West to East along the Gloria Fault up to the Northern Algerian margin. We model the surface velocity field and the ongoing lithospheric deformation using the most recent version of the thin-shell code SHELLS, and updated l...

The research program aimed on the in-depth understanding the volcano-tectonic evolution of the Azores plateau and associated geo-hazards such as submarine landslides and volcanic surges. Oceanic plateaus like the Azores plateau are large areas of anomalously thick crust forming large bathymetric swells in the ocean basins and their petrological for...

The Algarve Basin is a Meso-Cenozoic sedimentary basin overlying Carboniferous basement, located in the southwestern margin of the Iberian Peninsula. Its structure reveals a protracted tectonic history comprising various pulses of Mesozoic extension followed by Cenozoic compression. This work deals with the structure along the northern margin, wher...

Submarine mass failures represent one of the most significant marine geo-hazards. Their importance as a major contributor to tsunami generation and hazard has been recognized over the last 20–30 years. This study investigates a newly mapped submarine landslide, the South Hirondelle Landslide (SHL), and its potential to generate a tsunami and to thr...

Tectonic inversion of the SW Iberia passive margin has been documented mainly from the interpretation of reflection seismic and outcrop data. Inversion has occurred with two main styles: 1) Reactivation of Triassic-Jurassic extensional faults with uplift of syn-rifting basins and formation of broad anticlines. These thrusts cause uplift up to 450m...

A web-based reference for tsunami research around Europe

EU project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe, Project number: 603839) aims at reaching a higher level of tsunami resilience in the North East Atlantic and Mediterranean (NEAM) region by a combination of field work, experimental work, numerical modeling and technical development. The project is a cooperative wor...

Abstract The West Iberian Margin (WIM) preserves onshore testimonies of three Mesozoic magmatic cycles. In this paper, we present and discuss 40Ar/39Ar ages and geochemical data for the second cycle, which occurred at least from 148 Ma to 140 Ma, at the Jurassic-Cretaceous transition, during the late stages of an important extensional event associ...