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Quantifying Changes in the seismic velocity (dv/v) from repeating sources or ambient noise surveys is an established tool in seismology.dv/vhas been shown to correlate to a multitude of parameters such as stress variations, pore pressure changes, and modifications in the microscopic and macroscopic integrity of the sampled medium (i.e., “damage”). In turn, these parameters are impacted by an even greater number of mechanisms, for example, precipitation, temperature, surface loading, seismic activity, hydrology, volcanic activity, or tidal forces. However, their relationships todv/vare often non-linear, hard to quantify, and poorly understood. Additionally, for “field data”, it can be challenging to decipher the contribution of each individual parameter todv/v changes. In this work, we analyse continuous seismic data and interdisciplinary datasets from Mt St Helens (USA) and the Kamchatka peninsula (Russia) to illustrate the diversity of mechanisms impactingdv/vand discuss potential strategies to unravel the observations. We show that, for volcanic areas in particular, analysingdv/vis a complex task due to the addition of volcanic activity, high-relief topography, and strongly heterogeneous subsurface structures., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The ITU/WMO/UNESCO-IOC Joint Task Force for Science Monitoring and Reliable Telecommunications (JTF SMART) is working to integrate environmental sensors into trans-ocean commercial submarine telecommunications cables to construct a global deep ocean observing array. The telecommunication signal along cables is boosted by repeaters every 50-100 km; these will be equipped with pressure and temperature sensors and accelerometers. Real-time ocean-bottom observations will quantify changes in climate, ocean circulation, and sea level, enable life-saving tsunami and earthquake early warning, and yield new insights into tectonic and deep Earth processes. Thus, United Nations Sustainable Development Goals (i.e., SDG 9, 13, 14) are addressed. SMART Cables is an endorsed Project of the United Nations Decade of Ocean Science for Sustainable Development.We will review SMART systems and report progress toward realising that vision. Ocean modelling experiments are performed to quantify the benefits of SMART cables for monitoring Essential Ocean Variables and other characteristics. A wet demonstration system will be installed off Sicily in June 2023. Portugal has issued a request for tender for the 100% state-owned domestic CAM system connecting Continental Portugal, Azores, and Madeira in a 3700 km ring with 50 SMART repeaters to be installed in 2025. It is motivated by earthquake and tsunami disaster risk reduction, and improving understanding of the Atlantic Meridional Overturning Circulation. Further systems in various planning stages include Mediterranean, New Zealand-Chathams, Vanuatu-New Caledonia, Chile-Sydney, Chile-Antarctica, New Zealand-Antarctica, Indonesia, and Trans-Arctic Europe-Japan. Finally, the European Union has included SMART capability in its international submarine cable connectivity program (CEF2)., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

In last few years, a number of technologies to use fibre optic cables as sensing devices have been established, among them Distributed Acoustic Sensing (DAS) and State-of-Polarisation (SoP). The potential of these technologies for monitoring a range of Earth System parameters in submarine cables has been demonstrated through several pilot experiments. Yet, continuous access to sub-marine optical fibre scientific data has currently not been achieved anywhere, neither has full integration of the various techniques.The SUBMERSE project links Research and Education Networks (NRENs), universities, research institutes and industry to establish multi-method monitoring along submarine optical telecommunication cables at several key cable routes branching off from Portugal, Madeira, Svalbard and in the Aegean. Those pilot sites should serve as a blueprint for establishing continuous monitoring services along many more cables.The project comprises technical developments for integrating DAS and SoP measurements, for establishing differential SoP measurements between repeaters and for operating DAS in ‘lit’ fibres, i.e., fibres carrying telecommunications traffic. Furthermore, a range of geoscientific and marine biology use cases are included, which seek to establish code/services for monitoring earthquakes, tracking whales, measuring the sea state and other Earth System variables. Effective data management, dissemination and training through community specific services will be addressed in several tasks as they are crucial for the success of this project due to the large size of data, sensitivity of a subset of the recordings and current lack of established community standards. SUBMERSE clearly commits to open and FAIR data exchange., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The 22 December 2018 Anak-Krakatau volcanic flank collapse triggered a devastating tsunami along the Sunda Strait coast, highlighting the need for tsunami early warning systems to detect both volcanic collapse and landslide tsunami triggering from real-time seismic data. Seismically, landslides are deficient in high-frequency radiation compared to tectonic earthquakes. In this study, carried out in the framework of the TSUNAMI_RISK project, we implemented spectral analysis and back-projection to locate low-frequency events (40-70 s) along the Indonesian coast, specifically volcano-induced landslides. Using the Indonesian seismic network, we successfully detected and located the Anak-Krakatau volcanic flank collapse. The back-projection method allowed us to estimate the location about 100 seconds after the event initiation, with detection achieved with stations up to 1° from the source. To assess potential biases in our approach, we evaluated two weeks of continuous long-period seismic data (11-25 November 2019) from high-risk volcano tsunami areas in eastern Indonesia, such as Batu Tara, Iliwerung, Gamalama, and Sangeang Api. We conclude by discussing the expected false alarm rates for various warning thresholds based on the current network configuration in Indonesia and explore the routes to implementing this approach for operational tsunami early warning., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Understanding physical processes prior and during eruptions remains challenging, due to uncertainties about subsurface structures and undetected processes within the volcano. Here, the authors use a dedicated fibre-optic cable to obtain strain data and identify volcanic events and image hidden near-surface volcanic structural features at Etna volcano, Italy. In the paper Jousset et al. (2022), we detect and characterize strain signals associated with explosions, and we find evidences for non-linear grain interactions in a scoria layer of spatially variable thickness. We also demonstrate that wavefield separation allows us to incrementally investigate the ground response to various excitation mechanisms, and we identify very small volcanic events, which we relate to fluid migration and degassing. We recorded seismic signals from natural and man-made sources with 2-m spacing along a 1.5-km-long fibre-optic cable layout near the summit of actives craters of Etna volcano, Italy. Those results provide the basis for improved volcano monitoring and hazard assessment using DAS. This data publication contains the full data set used for the analysis. This data set comprises strain-rate data from 1 iDAS interrogator (~750 traces), velocity data from 15 geophones and 4 broadband seismometers, and infrasonic pressure data from infrasound sensors. For further explanation of the data and related processing steps, please refer to Jousset et al. (2022).

We present a new 3D shear-wave velocity model and Moho map of Scandinavia, which is based on the inversion of the merged phase dispersion curves from ambient noise and earthquake-generated Rayleigh waves. A classic two step inversion scheme is used where first maps of phase velocities at different periods are derived, and then a 1D transdimensional Bayesian method is applied to determine the VSV-depth structure. We assess the question of what compensates for the unusual high Scandes mountains and aim to identify the different tectonic domains of the adjacent continental lithosphere (Baltic Shield). While the southern Scandes lacks a pronounced crustal root, we observe a crustal root below the northern Scandes that is decreasing towards the central Scandes. A ∼10 km thick high-density lower crustal layer is present below the northern Scandes and generally thickening to the east below the Baltic Shield. The lithosphere-asthenosphere boundary (LAB) below the Scandes is deepening as well from west to east with a sharp step and a strong VSV decrease with depth of 9% in the north and of 5.5% in the south. The LAB of the thinner lithosphere is at 150 km depth in the north and varies from 90 to 120 km depth in the south. Both LAB steps coincide with the mountain front. The central area shows rather smoothly varying structures (170 km LAB depth, −4% VSV with depth) towards the east and no clear spatial match with the front. We infer therefore distinct uplift mechanisms along the Scandes. The southern Scandes might sustain their topography due to dynamic support from the mantle, while the northern Scandes experience both crustal and mantle lithosphere isostasy. In both cases, we suspect a dynamic support from small-scale edge-driven convection that developed at the sharp lithospheric steps. Beneath the Archean Karelia craton in northern Finland, we find low-velocity areas below 150 km depth while a 250 km deep lithospheric keel is imaged below the Paleoproterozic southern Finland. The Norrbotten craton in northern Sweden can be identified at mantle depths as a unit different from the Karelia craton, Scandes and Paleoproterozic central Sweden.

We present a new seismic tomography model for the crust and upper-mantle beneath the Central Andes based on multi-scale full seismic waveform inversion, proceeding from long periods (40–80 s) over several steps down to 12–60 s. The spatial resolution and trade- offs among inversion parameters are estimated through the multi-parameter point-spread functions. P and S wave velocity structures with a spatial resolution of 30–40 km for the upper mantle and 20 km for the crust could be resolved in the central study region. In our study, the subducting Nazca slab is clearly imaged in the upper mantle, with dip-angle variations from the north to the south. Bands of low velocities in the crust and mantle wedge indicate intense crustal partial melting and hydration of the mantle wedge beneath the frontal volcanic arc, respectively and they are linked to the vigorous dehydration from the subducting Nazca plate and intermediate depth seismicity within the slab. These low velocity bands are interrupted at 19.8-21° S, both in the crust and uppermost mantle, hinting at the lower extent of crustal partial melting and hydration of the mantle wedge. The variation of lithospheric high velocity anomalies below the backarc from North to South allows insight into the evolutionary foundering stages of the Central Andean margin. A high velocity layer beneath the southern Altiplano suggests underthrusting of the leading edge of the Brazilian Shield. In contrast, a steeply westward dipping high velocity block and low velocity lithospheric uppermost mantle beneath the southern Puna plateau hint at the ongoing lithospheric delamination.

The data publication contains a dataset for fast assessment of earthquakes based on seismic waveforms. The dataset encompasses Northern Chile. Due to the large scale of the dataset, it is intended for use in machine learning. A similar dataset for chile has been published as Münchmeyer et al. (2020). A similar dataset for Japan can be obtained using the scripts at https://github.com/yetinam/TEAM The datasets are provided as a hdf5-file (Folk et al. 2011), a hierachical file format. Source code for reading and processing the data is available at https://github.com/yetinam/TEAM. The hdf5-file contains the two groups “metadata” and “data” that are described below. These groups are the hdf5-analog of folders in a file system.

The temporary seismic array of MySCOLAR in northern Myanmar consists of 30 broadband stations. The overall scientific goals are to understand the transition from continental collision to oceanic subduction, to quantify the partitioning of deformation in the accretionary prism, in the Burma Plate and along the strike-slip Sagaing fault system and to image the subducting Indian Plate beneath Myanmar and southwest China. The seismological analysis methods applied to this dataset will include location of local earthquakes and determining their focal mechanisms, surface wave tomography from ambient noise and earthquake data, body wave tomography from local and teleseismic earthquakes, full waveform inversion for Earth structure, receiver functions, and shear wave splitting. A subset of the stations was transmitting data in real time, and these stations contributed to real-time earthquake analysis by the Department of Meteorology and Hydrology (DMH) in Myanmar and the GEOFON earthquake monitoring service. Waveform data are available from the GEOFON data centre, under network code 6C.

This dataset contains a high resolution Moho map of the in the Eastern Alps focused on the SWATH-D network. The Moho map was produced by manually picking the Moho on narrow transects (CCP stacks) calculated with the receiver function method. These manual picks were then fit with a spline in 3-D. Three separate and sometimes overlapping maps are included corresponding to the European, Adriatic, and Pannonian Mohos. In addition to Moho depth, Ps travel time and crustal average Vp/Vs are also reported.

A new seismic model for crust and upper mantle of the south Central Andes is derived from full waveform inversion, covering the Pampean flat subduction and adjacent Payenia steep subduction segments. Focused crustal low‐velocity anomalies indicate partial melts in the Payenia segment along the volcanic arc, whereas weaker low‐velocity anomalies covering a wide zone in the Pampean segment are interpreted as remnant partial melts. Thinning and tearing of the flat Nazca slab is inferred from gaps in the slab along the inland projection of the Juan Fernandez Ridge. A high‐velocity anomaly in the mantle below the flat slab is interpreted as relic Nazca slab segment, which indicates an earlier slab break‐off triggered by the buoyancy of the Juan Fernandez Ridge during the flattening process. In Payenia, large‐scale low‐velocity anomalies atop and below the re‐steepened Nazca slab are associated with the re‐opening of the mantle wedge and sub‐slab asthenospheric flow, respectively.

We investigate the anisotropic nature of the mantle in a part of the Arabia-Eurasia collision zone where several of the constituent tectonic blocks of Iran come into contact. Our aim is to identify the dominant source of anisotropy in order to infer the pattern of mantle deformation as it responds to the forces of continental convergence. The broadband seismic data used in this study were recorded by 68 seismic stations in three temporary arrays in NW Iran (between 45º00'E - 51º00'E and 35º00'N - 39º00'N) installed and operated non-concurrently between 2008 and 2016 by the Institute for Advanced Studies in Basic Sciences (IASBS) and the University of Cambridge, and one permanent station of the Iranian National Seismic Network (INSN). The stations were repositioned during deployment and the recording span at individual stations varied between 4 and 31 months. The temporary arrays were mainly linear profiles that traversed the Talesh and western Alborz Mountains, NW Iran, and parts of the central Iran Plateau to the vicinity of the UDMA. Our dataset includes seismic records of S and SK(K)S phases. For the SK(K)S splitting measurements we used teleseismic earthquakes with magnitudes greater than 5.5 and epicentral distances between 90º and 130º, and for the direct S phase analysis we considered events larger than magnitude 5.5 in the distance range of 40º to 80º.

The Anillo is a dense temporary seismic and geodetic network extending approximately 200 km along the strike of the subduction zone in North Chile in order to investigate how earthquakes and aseismic slip scale over a broader spectrum of source sizes, to understand the complex relationships between seismic and aseismic deformation, and to identify possible structural controls. This experiment is embedded into a larger scale experimental effort carried out by institutions in Germany and Chile. Waveform data are available from the GEOFON data centre, under network code Y6.

The Ethiopian rift is a unique natural environment to study the different stages of evolution from initial continental rifting to embryonic sea-floor spreading. We study the crust and uppermost mantle of the Afar, Main Ethiopian Rift and the adjoining plateaus using hierarchical Bayesian ambient seismic noise tomography. A shear wave velocity model of the crust is produced based on the point-wise linearized inversion of the dispersion curves extracted from the group velocity maps. This dataset provides 3-D shear velocity results from Eshetu et al. (2021). The file “3dmod.dat” contains the shear wave velocity model for the Ethiopian rift, sampled onto a regular grid. Poorly imaged cells are set to “nan”, see the main text for details. Note that the model primarly resolves S wave structure (Vs). P wave velocity (Vp) is not independently constrained but, during the inversion, calculated from Vs using empirical relations (Brocher, 2005).

Coda-Q is used to estimate the attenuation and scattering properties of the Earth. So far focus has been on earthquake data at frequencies above 1 Hz, as the high noise level in the first and second microseismic peak, and possibly lower scattering coefficient, hinder stable measurements at lower frequencies. In this work, we measure and map coda-Q in the period bands 2.5-5 s, 5-10 s and 10-20 s in the greater Alpine region using noise cross-correlations between station pairs, based on data from permanent seismic stations and from the temporary AlpArray experiment. The observed coda-Q for short interstation distances is independent of azimuth so there is no indication of influence of the directivity of the incoming noise field on our measurements. In the 2.5-5 s and 5-10 s period bands, our measurements are self-consistent, and we observe stable geographic patterns of low and high coda-Q in the period bands 2.5-5 s and 5-10 s. In the period band 10-20 s, the dispersion of our measurements increases and geographic patterns become speculative. The coda-Q maps show that major features are observed with high resolution, with a very good geographical resolution of for example low coda-Q in the Po Plain. There is a sharp contrast between the Po Plain and the Alps and Apennines where coda-Q is high, with the exception a small area in the Swiss Alps which may be contaminated by the low coda-Q of the Po Plain. The coda of the correlations is too short to make independent measurements at different times within the coda, so we cannot distinguish between intrinsic and scattering Q. Measurements on more severely selected data sets and longer time-series result in identical geographical patterns but lower numerical values. Therefore, high coda-Q values may be overestimated, but the geographic distribution between high and low coda-Q areas is respected. Our results demonstrate that noise correlations are a promising tool for extending coda-Q measurements to frequencies lower than those analysed with earthquake data.

The data publication contains a dataset for fast assessment of earthquakes and early warning based on seismic waveforms. The dataset encompasses Italy and surrounding refions. Due to the large scale of the dataset, it is intended for use in machine learning. A similar dataset for Japan, with the same specifications as the one provided in this data publications, can be obtained using the scripts at https://github.com/yetinam/TEAM

We study the crustal structure of Sri Lanka by analyzing data from a temporary seismic network deployed in 2016-2017 (Seneviratne et al., 2016) to shed light on the amalgamation process from the geophysical perspective. Rayleigh wave phase dispersion from ambient noise cross-correlation and receiver functions were jointly inverted using a transdimensional Bayesian approach (Bodin et al., 2012, Dreiling et al., 2019).

Volcanic and seismic activities produce a variety of phenomena that put population at risk. In order to assess the seismic and volcanic hazard, many instruments are deployed around active volcanoes and seismic fault zones. Their records are useful to observe the activity of the volcanoes and faults in order to understand better their behaviour and issue warnings to authorities in charge of the public security. In this study, we used optical cables around Etna volcano to observe seismic and pressure signals associated with volcanic activity. The 2018 expedition consisted of three experiments. Firstly, we used a 4-km long telecom line in Zafferana and recorded all geodynamic and other activities for about 20 days. At this site, the fibre is known to cross active faults that are linked to the eastern volcano flank slowly sliding towards the sea. Secondly, we tested a 40 km-long cable from an internet provider at the western side of the volcano. Thirdly, we used a fibre cable deployed at the summit area of the volcano to test its ability to detect small volcanic events. In each of the three parts, a DAS system (iDASTM interrogator provided by Silixa) sent repeatedly coherent light pulses with a gauge length of 10 m and deduced the strain rate from interferometric measurements of the back-scattered light. We were able to measure every 2 metres the strain rate associated with several volcanic event types, earthquakes and many other signals from human activity. We validated the optical records with records from additional sensors such as seismic broadband stations, geophones and infrasound sensors. We present results from all experiments.

The present dataset is a high-resolution earthquake catalog for the region of the 2014 M8.1 Iquique earthquake sequence, in the Northern Chile subduction zone. Events in the catalog were obtained processing seismic waveforms from >100 permanent and temporary seismic stations. The list of waveform data sources used, the multistage automatic earthquake detection and location procedure implemented to build the catalog, as well as the patterns outlined by the seismicity are described in Soto et al. (2019).

The ocean is key to understanding societal threats including climate change, sea level rise, ocean warming, tsunamis, and earthquakes. Because the ocean is difficult and costly to monitor, we lack fundamental data needed to adequately model, understand, and address these threats. One solution is to integrate sensors into future undersea telecommunications cables. This is the mission of the SMART subsea cables initiative (Science Monitoring And Reliable Telecommunications). SMART sensors would "piggyback" on the power and communications infrastructure of a million kilometers of undersea fiber optic cable and thousands of repeaters, creating the potential for seafloor-based global ocean observing at a modest incremental cost. Initial sensors would measure temperature, pressure, and seismic acceleration. The resulting data would address two critical scientific and societal issues: the long-term need for sustained climate-quality data from the under-sampled ocean (e.g., deep ocean temperature, sea level, and circulation), and the near-term need for improvements to global tsunami warning networks. A Joint Task Force (JTF) led by three UN agencies (ITU/WMO/UNESCO-IOC) is working to bring this initiative to fruition. This paper explores the ocean science and early warning improvements available from SMART cable data, and the societal, technological, and financial elements of realizing such a global network. Simulations show that deep ocean temperature and pressure measurements can improve estimates of ocean circulation and heat content, and cable-based pressure and seismic-acceleration sensors can improve tsunami warning times and earthquake parameters. The technology of integrating these sensors into fiber optic cables is discussed, addressing sea and land-based elements plus delivery of real-time open data products to end users. The science and business case for SMART cables is evaluated. SMART cables have been endorsed by major ocean science organizations, and JTF is working with cable suppliers and sponsors, multilateral development banks and end users to incorporate SMART capabilities into future cable projects. By investing now, we can build up a global ocean network of long-lived SMART cable sensors, creating a transformative addition to the Global Ocean Observing System.

In Münchmeyer et al. 2019 magnitudes scales for Northern Chile have been derived with a focus on low uncertainties. The data set consists of three parts. First, a version of the IPOC catalog with the derived magnitude scales ML and MA and their uncertainties. Second, the attenuation functions for different waveform features. Third, the full matrix of features and the resulting single station magnitude predictions.The underlying IPOC catalog was obtained from Sippl et al. (2018). Detailed data description is provided in the README and in Münchmeyer et al. (2019) to which these data are supplementary material.

Estimating small-scale VP/VS variations at depth can be a powerful tool to infer lithology and hydration of a rock, with possible implications for frictional behavior. In principle, from the differential arrival times of P and S phases from a set of spatially clustered earthquakes, an estimate of the local VP/VS can be extracted, because the VP/VS is the scaling factor between the P and S differential times for each pair of earthquakes. We critically review the technique proposed by Lin and Shearer (2007), in which the mean value over all stations is subtracted from the differential arrival times of each pair of events in order to make the method independent of a priori information on origin times. The demeaned differential P and S arrival times are plotted on a plane, and the VP/VS ratio is estimated by fitting the points on this plane. We tested the method by both theoretical analysis and numerical simulations of P and S travel times in several velocity models. We found that the method returns exact values of VP/VS only in the case of a medium with homogeneous VP/VS , whereas, when a VP/VS gradient is present, the estimates are biased as an effect of systematic differences between P and S takeoff angles. We demonstrated that this bias arises from the demeaning of the arrival times over the stations. In layered models with VP/VS decreasing with depth, we found that VP/VS is overestimated or underestimated, respectively, for takeoff angles larger or smaller than 90°. In mosst realistic local earthquake monitoring settings, the take-off angles are not equally distributed but there will be a dominance of downward going rays, resulting in an overall bias. We calculated analytically the dependence of this bias on the takeoff angles. Additional simulations showed that the difference between the calculated and the expected VP/VS is reduced for simple horizontally layered velocity structures (

Estimating small-scale V-P/V-S variations at depth can be a powerful tool to infer lithology and hydration of a rock, with possible implications for frictional behavior. In principle, from the differential arrival times of P and S phases from a set of spatially clustered earthquakes, an estimate of the local V-P/V-S can be extracted, because the V-P/V-S is the scaling factor between the P and S differential times for each pair of earthquakes. We critically review the technique proposed by Lin and Shearer (2007), in which the mean value over all stations is subtracted from the differential arrival times of each pair of events in order to make the method independent of a priori information on origin times. The demeaned differential P and S arrival times are plotted on a plane, and the V-P/V-S ratio is estimated by fitting the points on this plane. We tested the method by both theoretical analysis and numerical simulations of P and S travel times in several velocity models. We found that the method returns exact values of V-P/V-S only in the case of a medium with homogeneous V-P/V-S, whereas, when a V-P/V-S gradient is present, the estimates are biased as an effect of systematic differences between P and S takeoff angles. We demonstrated that this bias arises from the demeaning of the arrival times over the stations. In layered models with V-P/V-S decreasing with depth, we found that V-P/V-S is overestimated or underestimated, respectively, for takeoff angles larger or smaller than 90 degrees. Moreover, we calculated analytically the dependence of this bias on the takeoff angles. Our simulations also showed that the difference between the calculated and the expected V-P/V-S is reduced for simple horizontally layered velocity structures (< 0.06), whereas it is 0.27 in a more realistic velocity model mimicking a subduction zone.

On September 16, 2015, the convergent Chilean margin again experienced a great subduction megathrust earthquake. The MW=8.2 Illapel earthquake occurred in the Metropolitan segment north of where the Juan-Fernandez ridge meets the Chile trench and subduction style and geometry change over a short distance. Combining GPS displacement measurements, InSAR interferograms, strong motion data, broadband seismological waveforms and backprojection of high frequency teleseismic signals we derive a comprehensive description of the coseismic rupture. Further, we determine accurate depths for the mostly offshore aftershock sequence by careful observations of teleseismic depth phases and derive moment tensors for the larger earthquakes from waveform modelling of bodyand surface waves. The rupture nucleated near the coast but then propagated to the north and updip. The resulting simple rupture geometry is approximately circular with a peak slip of 6 m, and a diameter of approximately 100 km, centered below the middle slope of the forearc. Forward modelling of tsunami propagation for this model successfully predicts approximate tsunami wave heights measured at 3 tide gauges along the North Central Chile coast, confirming that the rupture diminished towards the trench. Similar to previous observations, high frequency seismic radiation is mostly emitted downdip of the region of most intense slip, but unlike in most previous events, the high frequency emitters do not track the whole rupture along-strike but are confined to a small region within ∼ 50 km of the epicenter. The time evolution of high frequency seismic radiation also peaks earlier than the long period rupture evolution, indicating that the final phase of the rupture progressed smoothly. The aftershocks extend significantly beyond the limits of the main rupture in both north and south direction; their pattern of propagation suggests triggering by coseismic changes to the Coulomb failure stress. Plate interface events dominate the aftershock sequence but there are also some thrust events in the forearc crust and some shallow normal faulting events in the oceanic crust below the trench. In 1943, an earthquake of comparable along-strike extent occurred in the Illapel area. The similar extent of the aftershock zone and tsunami heights therefore make this part of the margin a candidate site for generating characteristic earthquakes, in particular as the 1943 event was itself preceded by an event in 1880, again with apparently the same part of the margin affected. The approximate match of peak slip and accumulated slip deficit in the 72 years since the 1943 event also support this interpretation. However, the 1943 Illapel event appears to have had a shorter source time function and probably a smaller magnitude than the 2015 event, pointing to differences in the detailed rupture evolution. The coupling is mostly close to fully locked in this area at least along the coast line but nevertheless the coseismic rupture is associated with a local peak in the locking pattern, whereas a distinct narrow partially interseismically creeping area is found just to the south of the main rupture. The northern transition to lower locking is more gradual but also here the rupture can be said to have terminated against a zone of reduced locking. Although locally the recent Illapel earthquake has relieved much of the accumulated stress, the segment immediately adjacent to the north remains unbroken since 1922, and presents a serious earthquake and tsunami hazard.

On September 16, 2015, the Chilean margin experienced a great subduction megathrust earthquake. The MW=8.2 Illapel earthquake occurred in the Metropolitan segment north of where the Juan-Fernandez ridge meets the Chile trench and subduction style and geometry change. Combining GPS displacement measurements, InSAR interferograms, strong motion and broadband seismological waveforms, and high frequency (HF) teleseismic backprojection we derive a comprehensive description of the coseismic rupture. We further determine moment tensors and obtain accurate depth estimates for mostly offshore aftershock sequence by careful observations of teleseismic depth phases. The rupture nucleated near the coast but then propagated to the north and updip, with a circular geometry of diameter 100 km and a peak slip of ~6 m below the forearc. HF seismic radiation is mostly emitted downdip of the region of most intense slip, but unlike in most previous events the high frequency emitters do not track the whole rupture but are confined to a small region. The time evolution of HF seismic radiation also arrests earlier than the long period rupture evolution, indicating that the final phase of the rupture progressed more smoothly. The aftershocks, mostly plate interface events, extend significantly beyond the limits of the main rupture in both directions. In 1943, a comparable event struck the Illapel area. The similar extent of the aftershock zone and tsunami heights therefore make this part of the margin a candidate site for generating characteristic earthquakes. The approximate match of peak slip and accumulated slip deficit in the 72 years since the 1943 event also support this interpretation. However, the 1943 event appears to have had a shorter source time function and probably a smaller magnitude, pointing to differences in the detailed rupture evolution. The coupling is mostly close to fully locked in this area at least along the coast line but nevertheless the coseismic rupture is associated with a local peak in the locking pattern, whereas a narrow partially creeping area is found just to the south of the main rupture. Although locally the recent Illaped earthquake has relieved much of the accumulated stress, the segment immediately adjacent to the north remains unbroken since 1922, and presents a serious earthquake and tsunami hazard.

LITHOS-CAPP is the German contribution to the international ScanArray experiment. ScanArray is an array of broadband seismometers with which we aim to study the lithosphere and upper mantle beneath the Scandinavian Mountains and the Baltic Shield. LITHOS-CAPP contributed 20 broadband recording stations from September 2014 to October 2016, 10 in Sweden and 10 in Finland, continuously recordings at 100 samples per second. The stations were deployed by the KIT Geophysical Institute and GFZ section 2.4 (seismology). They form part of the temporary network ScanArrayCore (FDSN network code 1G 2012-2017), Scientific Technical Report STR - Data; 17/02, GIPP Experiment and Data Archive

Scientific Technical Report STR - Data; 17/06, The island of Madagascar occupies a key region in both the assembly and the multi-stage breakup of Gondwanaland, itself part of the super-continent Pangaea. Madagascar consists of an amalgamation of continental material with the oldest rocks being of Archaean age. Its ancient fabric is characterised by several shear zones, some of them running oblique to the N-S trend, in particular in the south of the island. More recently during the Neogene, moderate volcanism has occurred in the Central and Northern part of the island, and there are indications of uplift throughout Eastern Madagascar over the last 10 Ma. Although Madagascar is now located within the interior of the African plate and far away from major plate boundaries (>1000 km from the East African rift system and even further from the Central and South-West Indian Ridges), its seismic activity indicates that some deformation is taking place, and present-day kinematic models based on geodetic data and earthquake moment tensors in the global catalogues identify a diffuse N-S-oriented minor boundary separating two microplates, which appears to pass through Madagascar. In spite of the presence of Archaean and Proterozoic rocks continent-wide scale studies indicate a thin lithosphere (