Geological Survey Department

Tectonically complex areas can give rise to large heterogeneity in source properties, which have a direct impact on observed ground motion. On November 12, 2025, the Eastern Mediterranean island of Cyprus experienced two M5+ earthquakes just 5 hours apart. Initial locations by the Cyprus Geological Survey Department put the two epicenters within 2 km of each other, but 10 km apart in depth. Moment tensor inversions from long-period waveform data show the first event had a magnitude around Mw5.1, with the second event measured at Mw5.4. However, observed peak ground velocity and acceleration amplitudes were almost indistinguishable between the two events. In this work, we revisit these observations and try to reconcile them using joint analyses of earthquake relocations, moment tensors, observed ground motions, and finite fault modeling. We relocate the events using a non-linear, probabilistic location algorithm and model point source moment tensors, showing the events occurred close in space and at a very similar depth. We derive relative moment rate functions (MRFs) for the two events via empirical Green’s function deconvolution. We find the Mw5.1 shows simple, sub-second duration MRFs. On the other hand, the Mw5.4 exhibits multi-peaked, complex MRFs with pulse durations up to 4 times longer than those of the Mw5.1. This suggests a simple, fast rupture in the first event contrasting with a likely slow, sluggish, and complex rupture in the second. We run finite fault modeling to reconcile observed ground shaking with source properties. Finally, we interpret the ruptures in the context of the highly complex tectonics of the Cyprus arc.

Several sections of the upper part of the Kannaviou Formation in southwest Cyprus are described. All sections are characterized by planktonic microfossil groups that include foraminifera and radiolarians. The presence of the key species Hendersonites carinatus makes it possible to identify the middle–upper Campanian stratigraphic interval in deep-marine facies. Identification of Contusotruncana plummerae and H. carinatus allows us to recognize the C. plummerae–H. carinatus Beds (middle–upper Campanian). Radiolaria from the Kannaviou, Vretsia and Armou sections (upper part of the Kannaviou Formation) are represented by characteristic assemblages of the lower part (upper part middle–upper Campanian) of the Amphipyndax tylotus Zone (upper part middle/upper Campanian–Maastrichtian). A more accurate identification of the lower boundary of the A. tylotus Zone is based on the integrated planktonic foraminiferal and radiolarian biostratigraphy.

The Lambousa fishtank, an archaeological structure entirely carved in bedrock, can be easily recognized and measured in plan on Google Earth (GE). We surveyed in situ this excellent archaeological marker in 2016 through direct measurements using traditional field measurements, such as metric tapes and invar rods, and terrestrial photogrammetry, using Structure from Motion (SfM) methods. The bedrock on which the fishtank is founded is an Upper Pleistocene calcarenite also containing Persistrombus Latus. The age of the studied fishtank has not been previously published, but on the basis of the construction technique and the interpretation provided by [1] and references therein . We assume that it was built in the period between 2.1 and 1.8 ka BP, like similar fishtanks in the Mediterarranen area. Architectural structures consist of an evident crepido ora a stone base, and a tunnel which allows for sea water exchange during high tides. The aforementioned hole is well correlated with the crepido which lies around the fishtank. These architectural components allow to evaluate the palaeosea level with significant precision during the time when the fishtank was active. MIS 5.5 coastal deposits that outcrop in the study area are located at a maximum altitude of a few meters, while the inner margin of the MIS 5.5 terrace allows us to hypothesize a “quasi-tectonic stability” also in the long-term. We have also tested several GIA predictions of relative sea level at Lambousa for the past 3.5 kyr according to GIA models ICE-6G (VM5a), ICE-7G (VM7) and to the GIA model by Lambeck and Purcell (2015), obtained with the SELEN4 sea level equation solver.

Abstract We present the Malawi Active Fault Database (MAFD), an open‐access (https://doi.org/10.5281/zenodo.5507190) geospatial database of 113 fault traces in Malawi and neighboring Tanzania and Mozambique. Malawi is located within the East African Rift's (EAR) Western Branch where active fault identification is challenging because chronostratigraphic data are rare, and/or faults are buried and so do not have a surface expression. The MAFD therefore includes any fault that has evidence for displacement during Cenozoic East African rifting or is buried beneath the rift valley and is favorably oriented to the regional stresses. To identify such faults, we consider a multidisciplinary data set: high‐resolution digital elevation models, previous geological mapping, field observations, seismic reflection surveys from offshore Lake Malawi, and aeromagnetic and gravity data. The MAFD includes faults throughout Malawi, where seismic risk is increasing because of population growth and its seismically vulnerable building stock. We also investigate the database as a sample of the normal fault population in an incipient continental rift. We cannot reject the null hypothesis that the distribution of fault lengths in the MAFD is described by a power law, which is consistent with Malawi's relatively thick seismogenic layer (30–40 km), low (<8%) regional extensional strain, and regional deformation localization (50%–75%) across relatively long hard‐linked border faults. Cumulatively, we highlight the importance of integrating onshore and offshore geological and geophysical data to develop active fault databases along the EAR and similar continental settings both to understand the regional seismic hazard and tectonic evolution.

Picrolite artefacts comprise some of the most distinctive material remains in the prehistory of the island of Cyprus, in the Eastern Mediterranean. Picrolite exploitation dates from at least 12,000 years ago for the manufacture of personal ornaments and items with a symbolic function. It is commonly assumed that picrolite nodules were collected in secondary deposits on an ad hoc basis. This narrative, however, ignores the fact that picrolite carriers can only be found in very specific locations on the island, discrete from each other. Here we report initial outcomes of the application of handheld portable X-ray fluorescence (HHpXRF) and synchrotron-based X-ray fluorescence spectroscopy (SR-μXRF) to the analysis of picrolite raw materials performed at the newly opened PUMA beamline of the SOLEIL Synchrotron Radiation Facility. Our work refines the basic characteristics of the elemental constituents of the picrolite raw material and highlights key micro-structural differences between two distinct source regions on the Troodos Massif in western Cyprus. Picrolite source characterisation is expected to contribute significant new knowledge to the study of rare raw material consumption, prehistoric social organisation, networking and possible long-distance exchange of this idiosyncratic raw material within and beyond the island’s geographic boundaries.

<p>The island of Cyprus sits at the boundary between the Anatolian and African plates, at a transition between oceanic subduction and incipient continental collision. Seismicity has been recorded here for millenia, with at least 12 town-destroying earthquakes recorded over the last 2,000 years. However, the instrumental coverage on the island has remained poor until relatively recently, and there is no bespoke velocity model or local magnitude scale, meaning that local seismicity is relatively poorly understood. Larger earthquakes, mainly to the south and west of the island, have revealed a mix of strike-slip and reverse faulting mechanisms. More enigmatic is the onshore seismicity, and questions remain over deformation within the Cyprus slab and uplift mechanisms of the Troodos ophiolite. We investigate seismicity in and around the island, in order to better understand these processes and their associated seismic hazard. We combine records of a temporary deployment of five broadband seismometers with the 13 permanent broadband seismometers on the island, as well as two accelerometers, to create a two-year local earthquake catalogue. We locate earthquakes both within the overriding Cyprus crust and the underthrusting African plate, and identify previously unrecognised seismically active regions on the island, especially around the Troodos ophiolite. We use this earthquake catalogue to constrain a new 1-D velocity model and local magnitude scale for the region. We also constrain new focal mechanisms and interpret these in the context of the regional tectonics.</p>

The present study describes the Pliocene paleoenvironmental evolution and the main paleoclimatic trends of Cyprus Island (southeastern Mediterranean) reconstructed using planktonic foraminifera. The Essovouyes-Exovouyes section, which is located on the boundary of Messaoria basin in the north and Larnaka basin in the south, corresponds to a continuous record from 5.21 to 1.8 Ma and therefore provides good data for the paleoclimatic reconstruction northeast of the Troodos mountain range. The sedimentary sequence of the studied section is about 90 meters thick and characterized of pinkish to brownish massive marls, rhythmic sedimentary cycles of yellow to light grey homogeneous marls and brownish organic-rich laminated layers, brown to light grey sandy marls, light yellow marly sands enriched in macrofossils, and yellow massive fine- to coarse-grained bioclastic calcarenites at the top. We particularly focused on its middle part (3.9-3.0 Ma time interval), which consists of well-preserved cyclic marine sediments, including organic-rich laminated brownish sapropelitic layers alternating with grey homogeneous marls. This part of the section was measured and sampled at 0.1 to 0.55 m intervals, which allowed us to perform a detailed biostratigraphic analysis. Seven astronomically dated planktonic foraminiferal bioevents were recognized and constrained the age model of the studied interval through the linear interpolation. Within this biostratigraphic framework, the first occurrence of Globorotalia crassaformis is highlighted in this study and confirms the presence of the Zanclean/Piacenzian boundary (3.6 Ma). Integrated micropaleontological, sedimentological, and geochemical (Total Organic Carbon; TOC, and stable oxygen and carbon isotope; δ18O, δ13C) analyses revealed the presence of numerous cycles that resulted in the sapropelitic/homogeneous marl alternations. The sapropelites developed around the Zanclean/Piacenzian boundary suggest a climate characterized by fluctuations of warm/temperate to humid conditions associated with a highly stratified water column at times of precession minima. Moreover, long term trends in oxygen isotopes are correlated with the sea surface temperature (SST) record derived from the planktonic foraminiferal assemblages (Planktonic Paleoclimatic Curve; PPC) and mostly reflect changes in global climatic conditions, with a more local or regional signal superimposed on this record. In particular, both the PPC and δ18O records indicate three distinct warm periods interrupted by two cooling events centred at 3.62 and 3.54-3.36 Ma respectively. Furthermore, the statistical analysis of the planktonic foraminifera revealed that the surface primary productivity and temperature show the highest explanatory power for their distribution and influence the hydrological regime of the studied area. Overall, this work confirms that multidisciplinary strategies and multiproxy study performed on Neogene sections can provide a powerful tool for monitoring the palaeoclimatic evolution of the eastern Mediterranean in relation to the global climatic system over the Pliocene.

Abstract We used aeromagnetic and satellite gravity data to investigate lithospheric structure beneath the Cretaceous Chilwa Alkaline Province (CAP) in southern Malawi and adjacent Mozambique. The CAP consists of granites, syenites, nepheline syenites, basanites, phonolite dikes, and minor carbonatite bodies. The intrusions were emplaced in the Precambrian (Mesoproterozoic‐Neoproterozoic) terranes of the Southern Irumide and Mozambique orogenic belts. Aeromagnetic data show the CAP as overlapping circular anomalies typical of nested igneous ring complexes formed through caldera collapse mechanism. We used gravity data to infer that: (1) the CAP was sourced from ~30‐km wide igneous bodies now preserved in the upper crust at ~5‐km depth. (2) the CAP is underlain by up to ~45‐km thick crust (due to mafic magmatic underplating) and a lithosphere as thin as ~90 km. These data suggest that mafic magmatic underplating and lithospheric thinning occurred during a Cretaceous rifting event. We propose, based on these results and taking into account previous petrographic, geochemical, geochronological, and isotopic studies, that the silica undersaturated magmatic phase of the CAP was due to flux melting of the asthenosphere. This was followed by silica‐rich magmatic phase due to decompression melting of the asthenosphere as a result of lithospheric thinning. Lithospheric thinning and ascendance of the asthenospheric melt might have been facilitated by the presence of late Neoproterozoic to early Cambrian suture zone. The heat provided by the mafic magmatic underplating resulted in partial melting of the lower crust to form the silica‐saturated CAP intrusions from mixed magma sources.