Pauline Galea

University of Malta · Department of Physics

This study employs a multimethod approach to investigate the sediment distribution in two pocket beaches, Ramla Beach and Mellieha S Beach, in Malta. Both study sites were digitally reconstructed using unmanned aerial vehicle (UAV) photogrammetry. For each case, an ERT and a dense network of ambient seismic noise measurements processed through a ho...

The limestone islands of Malta face high levels of water stress due to low rainfall over a small land area and a high population density. We investigate an innovative, cost-effective approach to groundwater monitoring in an island environment by computing auto- and cross-correlations of ambient seismic noise recorded on short-period and broadband s...

This study reports the results obtained by combining geophysical methods and geomatis techniques to study the Xrobb l-Ghagin archaeological site. We use unmanned aerial vehicle equipped with different sensors in order to reconstruct the 3D digital model of the area with the main goal of obtaining quantitative information. In particular, we used opt...

The southern coast of Sicily and the islands of the archipelagos of Malta are highly exposed to risks coming from the sea. Such coasts are subjected to fast erosion due to natural and anthropic causes which involve the failure of cliffs, the triggering of localized erosions and the possibility of flooding. In this context the Project NEWS-Nearshore...

In recent years, we have been witnessing the widespread use of low-cost, increasingly high-performance Unmanned Aerial Vehicles, or UAVs, equipped with a large number of sensors capable of extracting detailed information on several scales and in an immediate manner. This study was motivated by the need to perform a geological survey in an area with...

We present the results of an Italian-Maltese research, carried out to collect the macroseismic data needed to update the seismic catalogue of the Maltese Islands [Galea, 2007]. In this work we adopted the most up-to-date criteria developed by Italian historical seismology, obtaining results that significantly improve knowledge, particularly for the...

The Sicily Channel, situated on the leading edge of the African plate as it collides with Europe, presents a range of interesting and complex tectonic processes that have developed in response to various regional stress fields. The characterization and interpretation of the seismic activity, however, still presents a challenge. The Maltese islands,...

Earthquake ground motion is dependent on various factors, including local ground conditions. Whilst many studies have characterized the effect of having outcropping “soft” geological layers which have the ability to amplify ground motion, there is minimal literature on the effect of having such layers embedded between two harder layers. This situat...

It is known that local geology can alter the ground motion characteristics at a particular site. Whereas some sites are characterised by outcropping low-velocity layers, others might have buried ones of considerable thickness which might still be a cause of ground motion amplification. The Maltese islands (Central Mediterranean) provide a good case...

We present the first earthquake catalogue for Malta using 20 years of broadband seismic data recording. For about two decades Malta had only one station (WDD) which formed part of regional networks. Its location in the eastern part of the Sicily Channel puts the station at the periphery of these networks with the result that weak, off-shore earthqu...

Għajn Ħadid Tower represents an important cultural heritage of Malta (Central Mediterranean Sea). This tower, built in 1658 on the Selmun Promontory on the northeast coast of the island, was severely damaged by the 1856 Crete earthquake (MW 7.7). The area where the tower ruins stand is involved in a significant landslide process of lateral spreadin...

Spectacular landforms, both coastal and inland, on the Maltese Islands, are directly related to mainly vertical tectonic movements that mostly occurred within the past 10 million years. These movements form part of complex geodynamical processes that have shaped the Central Mediterranean and are still active today. A simple stratigraphic sequence o...

In this article an overall procedure is proposed, for the numerical investigation of the structural response of ancient monuments made of megalithic stones. The procedure is implemented on the middle temple of the Mnajdra Megalithic structure, listed as UNESCO World Heritage and regarded as one of the oldest structures from early civilization datin...

The co‐cathedral of St. John in Valetta, Malta represents a unique monument of historical importance. In this article, we present the results of a detailed GPR campaign performed in this co‐cathedral. The campaign was aimed at investigating the distribution of buried tombs under the mosaic floor of the main nave and of the lateral chapels of the co...

The last known significant tsunami to have hit the Maltese islands was in 1908 following the magnitude >7 Messina earthquake. It is reported that the sea around Malta became agitated and water rushed up inland. Fortunately, there were no casualties. If such an event were to recur, the impact on today’s coastal urban development would be significant...

A key prerequisite to efficiently monitor seismic activity is the appropriate planning and deployment of seismic stations of a local network. The effectiveness of a recently extended local network in the Maltese Islands and applications of various methodologies on its data, are presented and further discussed. Using the data of the enhanced network...

The Sicily Channel, bordered by the Sicilian and Tunisian coastlines, the Sicily-Malta escarpment to the east, and the Maghrebian thrust front to the west, is a tectonically interesting region, encompassing a NE-directed exten-sional process superimposed on the NW-directed thrust of Africa onto Europe. The extension is bathymetrically represented i...

Seventeenth century coastal watch towers, which are part of the Maltese cultural heritage, are at risk due to natural processes such as coastal weathering, erosion and land movement. In some cases, this makes them even more vulnerable to earthquake ground shaking and thus subjected to a possible considerable seismic risk. In this study, we present...

Mnajdra is a megalithic temple complex located in the south of Malta. It consists of three buildings facing a common oval forecourt and listed as a UNESCO World Heritage Site since 1992. Mnajdra’s Central temple (as well as the small one on the eastern side) is built on an artificial platform while the Lower Temple is built directly on hard rock. I...

The Azure Window was the name given to an imposing natural arch on the northwestern coast of the island of Gozo, the second largest island of the Maltese archipelago, Central Mediterranean. The geomorphological feature, carved in the Lower Coralline Limestone formation, was an iconic landmark for Gozo. It was also well known internationally as one...

The cliff slope of the Selmun Promontory, located in the Northern part of the island of Malta (Central Mediterranean Sea) close to the coastline, is involved in a landslide process as exhibited by the large block-size talus at its bottom. The landslide process is related to the geological succession outcropping in the Selmun area, characterized by...

The Victoria Lines Fault (island of Malta) is a >15 km-long and N260°-striking segmented normal fault-system, which is probably inactive since the late Pliocene. In the westernmost part, the Fomm Ir-Rih segment displays comparable geologic throw and escarpment height (~150–170 m), moreover its hangingwall hosts thin patches of Middle Pleistocene cl...

Seismic site response analysis is an important procedure used to obtain parameters such as peak ground motion values. These are needed by the engineering community for reliable seismic design, analysis and retrofitting of structures. One of the inputs for such analysis is the shear-wave velocity profile (VS) of the site. Surface wave methods are in...

The tectonic setting of the Maltese islands is mainly influenced by two dominant rift systems belonging to different ages and having different trends. The first and older rift created the horst and graben structure in northern Malta. The second rift generation, in the south, including the Maghlaq Fault, is associated with the Pantelleria Rift. The...

he geology of the Maltese islands is relatively young, with the oldest formations dating back only to the Tertiary period. The structural setting of the Islands is mainly influenced by two rift systems belonging to different ages and having different trends. The older rift generation creates a horst and graben structure in northern Malta. The secon...

We performed geophysical investigations in the northwestern sector of the island of Malta to reconstruct velocity-depth models and provide shear-wave velocity profiles. We have chosen two sites, one located in Rabat (Malta) and another in the Golden Bay area. We used both active (seismic and electrical 2D-tomography, Multichanel Analysis of Surface...

On December 28, 1908 at 5:20 a.m. local time, a devastating earthquake (Mw = 7.2) struck Southern Italy along the Messina Strait (Fig. 1). This event caused severe ground shaking throughout the region and triggered a local tsunami. As result the cities of Messina along Sicily’s coast and Reggio di Calabria were completely destroyed (Baratta, 1910)...

In the last forty years, Malta has only experienced a few occasional tremors from local or regional earthquakes, with only some being reported briefly in the local newspapers. These reports gave limited qualitative and quantitative information about the shaking experience felt across the islands. The Seismic Monitoring and Research Unit at the Univ...

In this paper we report results from an integrated measurement campaign performed on the island of Malta. Both GPR and seismic noise data were gathered in two sites close to the sea, where two watchtowers built by the Order of St. John are located. The two investigations were performed on the top of the cliff inGolden Bay, close to the Ghajn Tuffie...

The islands composing the Maltese archipelago (Central Mediterranean) are characterised by a four-layer sequence of limestones and clays. A common feature found in the western half of the archipelago is Upper Coralline Limestone (UCL) plateaus and hillcaps covering a soft Blue Clay (BC) layer which can be up to 75 m thick. The BC layer introduces a...

It is well known that earthquake damage at a particular site depends on the source, the path that the waves travel through and the local geology. The latter is capable of amplifying and changing the frequency content of the incoming seismic waves. In regions of sparse or no strong ground motion records, like Malta (Central Mediterranean), ground mo...

International Conference Georisks in the Mediterranean and their Mitigation University of Malta - Valletta Campus 20-21 July 2015

In the present study we attempt to construct seismic hazard model and produce probabilistic seismic-hazard assessments for the Maltese Islands in terms of Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) at different periods within the archipelago boundaries. So far very few investigations have been carried out on seismicity around the...

Weak to moderate earthquakes in the Sicily Channel have until now been either poorly located or left undetected. The number of seismic stations operated by various networks: Italy (INGV), Tunisia (TT), and Libya (LNSN) have now improved considerably, however most of the seismicity occurs offshore, in the central part of the Channel, away from the m...

Geography of perception aims at clarifying human behaviour by studying the concepts and images of the real world that a person elaborates on by considering the psychological and social aspects of man's behaviour within an environment. In this context, a questionnaire was given to primary and middle school pupils in an area of Calabria (Southern Ita...

The islands composing the Maltese archipelago (Central Mediterranean) are characterised by a four layer sequence of limestones and clays, with the Lower Coralline Limestone being the oldest exposed layer. The hard Globigerina Limestone (GL) overlies this layer and is found outcropping in the eastern part of Malta and western part of Gozo. The rest...

Anchor Bay and surrounding regions are located on the northwest coast of the island of Malta, Central Mediterranean. The area is characterized by a coastal cliff environment having an outcropping layer of hard coralline limestone (UCL) resting on a thick (up to 50 m) layer of clays and marls (Blue Clay, BC). This configuration gives rise to coastal...

The Central Mediterranean is a region of active tectonics characterised by the interaction of a number of varied and sometimes poorly understood processes. Superimposed on the convergent scenario of the African plate pushing northwestward, a NE–SW directed extensional regime is active in the Sicily Channel, expressed in the form of a seismically ac...

The Central Mediterranean is a region of active tectonics characterised by the interaction of a number of varied and sometimes poorly understood processes. Superimposed on the convergent scenario of the African plate pushing northwestward, a NE–SW directed extensional regime is active in the Sicily Channel, expressed in the form of a seismically ac...

The continual operation of a permanent seismograph, now exceeding a couple of decades in some cases, naturally involves changes of hardware and software over time. Nonetheless, the long-term, consistent performance of the seismic station, and the good quality of its data, is very important for national seismic studies investigating the local seismi...

The Maltese islands form an archipelago of three major islands lying in the Sicily channel at about 140 km south of Sicily and 300 km north of Libya. So far very few investigations have been carried out on seismicity around the Maltese islands and no maps of seismic hazard for the archipelago are available. Assessing the seismic hazard for the regi...

The Maltese islands in the Central Mediterranean are composed of a simple 4-layer sedimentary sequence of Oligocene-Miocene limestones and clays, highly disturbed by synsedimentary to recent tectonic activity, so that the surface outcrops present a variety of lithologies, as well as complex geomorphology. The seismic history of the islands includes...

The main goal of this study is to investigate the dynamic properties of main lithotypes outcropping on the island of Malta and to evaluate the general features of the local seismic response through the combined use of geophysical methods based on Rayleigh waves and horizontal to vertical noise spectral ratios. These kind of studies have unfortunate...

Anchor Bay and surrounding regions are located on the northwest coast of the island of Malta, Central Mediterranean. The area is characterized by a coastal cliff environment having an outcropping layer of hard coralline limestone (UCL) resting on a thick (up to 50m) layer of clays and marls (Blue Clay, BC). This configuration gives rise to a number...

Landslide phenomena involve the northern coast of Malta, affecting in particular the urban area of Xemxija. Limestones overlying a clayey formation represent the shallower lithotypes that characterize the surficial geology of this area, where lateral spreading phenomena and rockfalls take place. Ambient noise records, processed through spectral rat...

This research was carried out using computational facilities procured through the European Regional Development Fund, Project ERDF-080 ‘A supercomputing laboratory for the University of Malta (http://www.um.edu.mt/research/scienceeng/erdf_080).

The seismicity of the Sicily Channel, bordered by the Sicilian, Tunisian, and Libyan coastlines, is mainly controlled by active faults of the Sicily Channel rift zone (SCRZ). This region is characterized by a moderate level of earthquake activity with magnitudes generally below 5.0. However, most seismicity, especially south of the Maltese islands,...

A shallow aftershock sequence in the Hawkes Bay region of the North Island, New Zealand (May 1990) was recorded with high quality on an L-shaped, 7-station array of 3-component, short-period seismographs at Wellington, such that the seismic waves travelled almost along strike of the subducted Pacific plate in this region. The arrival times at the s...

A historical catalogue of felt earthquakes in the Maltese islands has been compiled dating back to 1530. Although no fatalities were officially recorded during this time as a direct consequence of earthquake effects, serious damage to buildings occurred several times. In the catalogue time period, the islands experienced EMS-98 intensity VII-VIII o...

A set of high quality aftershock data recorded on a closely spaced network of seismographs at Wellington, New Zealand, has enabled the determination of apparent wavefront speeds and azimuths controlled by the subducting Pacific plate. The former were very high (8.7 ± 0.2 km s-1) and the latter were shifted by as much as 10d̀ eastward of the source-...

The negative P-residuals, from readings at stations on Niue, Rarotonga and the Chatham Islands of shallower events along the Tonga-Kermadec trench and below the North Island, New Zealand, exhibit a scatter too large to be accounted for solely by observation and mislocation errors. The corresponding wavepaths cover a range of propagation azimuths be...

The Maltese Islands in the Central Mediterranean are composed of a simple 5-layer sedimentary sequence of Oligocene - Miocene age. The sequence is highly disturbed by syn-sedimentary to recent faulting, and the islands are characterised by a variety of outcropping rock types and underlying lithology. The seismic history of the Maltese islands inclu...