ALBERT

Description: The NEAM Tsunami Hazard Model 2018 (NEAMTHM18) is a probabilistic hazard model for tsunamis generated by earthquakes. It covers the coastlines of the North-eastern Atlantic, the Mediterranean, and connected seas (NEAM). NEAMTHM18 was designed as a three-phase project. The first two phases were dedicated to the model development and hazard calculations, following a formalized decision-making process based on a multiple-expert protocol. The third phase was dedicated to documentation and dissemination. The hazard assessment workflow was structured in Steps and Levels. There are four Steps: Step-1) probabilistic earthquake model; Step-2) tsunami generation and modeling in deep water; Step-3) shoaling and inundation; Step-4) hazard aggregation and uncertainty quantification. Each Step includes a different number of Levels. Level-0 always describes the input data; the other Levels describe the intermediate results needed to proceed from one Step to another. Alternative datasets and models were considered in the implementation. The epistemic hazard uncertainty was quantified through an ensemble modeling technique accounting for alternative models’ weights and yielding a distribution of hazard curves represented by the mean and various percentiles. Hazard curves were calculated at 2,343 Points of Interest (POI) distributed at an average spacing of ∼20 km. Precalculated probability maps for five maximum inundation heights (MIH) and hazard intensity maps for five average return periods (ARP) were produced from hazard curves. In the entire NEAM Region, MIHs of several meters are rare but not impossible. Considering a 2% probability of exceedance in 50 years (ARP≈2,475 years), the POIs with MIH 〉5 m are fewer than 1% and are all in the Mediterranean on Libya, Egypt, Cyprus, and Greece coasts. In the North-East Atlantic, POIs with MIH 〉3 m are on the coasts of Mauritania and Gulf of Cadiz. Overall, 30% of the POIs have MIH 〉1 m. NEAMTHM18 results and documentation are available through the TSUMAPS-NEAM project website (http://www.tsumaps-neam.eu/), featuring an interactive web mapper. Although the NEAMTHM18 cannot substitute in-depth analyses at local scales, it represents the first action to start local and more detailed hazard and risk assessments and contributes to designing evacuation maps for tsunami early warning.

Description: We analyzed the coseismic and early postseismic deformation of the 2015, Mw 8.3 Illapel earthquake by inverting 13 continuous GPS time series. The seismic rupture concentrated in a shallow (〈20 km depth) and 100 km long asperity, which slipped up to 8 m, releasing a seismic moment of 3.6 × 1021 Nm (Mw = 8.3). After 43 days, postseismic afterslip encompassed the coseismic rupture. Afterslip concentrated in two main patches of 0.50 m between 20 and 40 km depth along the northern and southern ends of the rupture, partially overlapping the coseismic slip. Afterslip and aftershocks confined to region of positive Coulomb stress change, promoted by the coseismic slip. The early postseismic afterslip was accommodated ~53% aseismically and ~47% seismically by aftershocks. The Illapel earthquake rupture is confined by two low interseismic coupling zones, which coincide with two major features of the subducting Nazca Plate, the Challenger Fault Zone and Juan Fernandez Ridge.

Description: Quaternary deformation in the northern Chile forearc is controlled by trench parallel shortening along reactivated Mesozoic faults. Dextral strikes-slip is expressed in NW–SE striking faults of the Atacama Fault System, and reverse displacement dominates in E–W faults. This deformation results of the convergence in a concave-seaward continental margin. On September 11th, 2020, a Mw 6.3 earthquake and its subsequent aftershocks took place in the coastal region of northern Chile, revealing the reactivation of the deepest segment of a WNW–ESE striking upper plate fault. The reactivation of this fault occurred after the Mw 8.1 Iquique earthquake, and it seems to be connected to a N–S interplate locking segmentation of the plate margin, which is clearly shown by the locking pattern before the Iquique earthquake. This poses the question of how heterogeneous locking influences upper plate seismicity and how it relates to trench-parallel shortening.

Description: Seismic-noise tomography is routinely applied for imaging geological structures at different spatial scales. The frequently used time-domain approach presents two limitations. First, extracting surface-wave group velocities from time-domain cross-correlations requires interstation distances of at least three wavelengths, which may be problematic when working at local or regional scales. Second, the presence of higher modes of surface waves in the cross-correlation functions is often disregarded, which may cause loss of valuable information about the shear-wave velocity structure. In this work, we present a complete inversion scheme that avoids these limitations, and use it to obtain a 3D shear-wave velocity model of the Basque–Cantabrian Zone (N Spain), a structurally complex area affected by multiple tectonic events. The resulting model agrees with the existing geological and geophysical knowledge and significantly extends the area for which high-resolution information is available.

Description: We present GNSS data from a survey-mode network located in the Central Betic Cordillera. The Betic Cordillera is a collisional orogen, presently undergoing NNW-SSE shortening, as it is located in the convergence limit between Nubia and Eurasia Plates. Our GNSS network includes seven stations along a ca. 170 km long NE-SW striking profile. For these stations we calculated GNSS velocities from position time series. Then we calculated residual velocities with respect to a fixed Eurasia (ITRF2014 plate motion model(Altamimi et al., 2017)'}" id="614029728"〉). To discuss our data in terms of regional geodynamic implications we projected the velocity vectors along the N060E direction. The absolute value of the N060E component of the obtained vectors shows a general increase of velocity from NE to SW, pointing to a regional NE-SW extension. This is in good agreement with previously reported data. Our data permit us to quantify an extension rate of 2.0±0.3 mm/yr. Furthermore, we also quantify the strain partitioning within the Central Betic Cordillera, including the Guadix-Baza and the Granada basins areas of high extensional rates, separated by a low-deformed crustal horst. Therefore, the Central Betic Cordillera is an area undergoing 2.0±0.3 mm/yr of NE-SW extension within a collisional orogen. Furthermore, this area presents the highest topographic relive of the entire cordillera and an overthickenedcrust. We thus postulate that the extension quantified by our GNSS data could partially be the consequence of upper crustal extension related to gravitational instability. This instability would be produced by the overthickened crust.

Description: First steps towards digital oceans rely on connecting datasets, harmonizing criteria and providing data access to wider user communities, but along the time, different storage codes have been adopted by the data providers according their own needs. The National Oceanographic Data Centre (NODC) is performing a strong effort in order to unify its datasets, making easier their identification and access. In the framework of (International Oceanographic Data Exchange, (UNESCO/IOC/IODE) initiatives, the IEO maintains a standardized catalogue of oceanographic surveys (CSR), integrated in international repositories as SeaDataNet or POGO. Although this activity has suffered ups and downs over 50 years of activity, the updating results sums up more than 4000 entries, including foreign surveys in national waters. Linked to it, the whole discrete water sampled analysis dataset has been renamed, profile by profile, following the same adopted naming criteria that CSRs. This assesses the uniqueness, prevent duplicates an improve their accessibility. More than 16000 profiles have been revised and updated following this approach, improving data access and allowing better storage protocols. The initiative accomplishes the european adopted criteria for metadata and data storage formats. A Geonetwork -OGC standard- catalogue possibilities the access to this information and data to a wide end-users community. As a case study, the information of the monthly standard oceanographic section of A Coruna (NW of Spain) is implemented in a local Geonetwork catalogue. Information about cruises and profiles is freely available. The technological harvesting capacities and machine to machine connections, increases the data visibility and reusing.

Description: Basin modeling in structurally complex areas involves several difficulties associated with its geometric and thermal history approaches. There have been multiple developments concerning the structural geometry in doing three-dimensional (3-D) basin modeling in these settings. However, their applicability is limited because most of these improvements require 3-D structural restorations, which is an input that is not always available at basin scale. Although a traditional basin model using backstripping could give a faster overview of the petroleum system elements, it is an alternative method that may distort the structural evolution and, consequently, the petroleum potential evaluation. Equally important are the thermal history uncertainties in these environments, where several factors disturb the thermal regime. Despite these difficulties, traditional 3-D basin modeling could be a reliable tool when we are able to understand the geometric and thermal histories and implement the proper adjustments. We propose alternative methods to tackle common problems when building 3-D basin models, and we demonstrate their validity with an example in the Middle Magdalena Valley, Colombia. This hydrocarbon province located in the northern Andes corresponds to an intermountain basin that has undergone a complex evolution. Its structural configuration represents a modeling challenge by means of the backstripping method. Additionally, a high variability exists in the present-day basal heat flow related to its structural evolution. The result of our model not only fits the calibration data, but also reflects the geological processes better. The proposed methodology intends to aid basin modelers in providing additional options when modeling in structurally deformed basins.

Description: Space weather driven atmospheric density variations affect low Earth orbit (LEO) satellites during all phases of their operational lifetime. Rocket launches, re-entry events and space debris are also similarly affected. A better understanding of space weather processes and their impact on atmospheric density is thus critical for satellite operations as well as for safety issues. The Horizon 2020 project Space Weather Atmosphere Model and Indices (SWAMI) project, which started in January 2018, aims to enhance this understanding by: - Developing improved neutral atmosphere and thermosphere models, and combining these models to produce a new whole atmosphere model. - Developing new geomagnetic activity indices with higher time cadence to enable better representation of thermospheric variability in the models, and improving the forecast of these indices. The project stands out by providing an integrated approach to the satellite neutral environment, in which the main space weather drivers are addressed together with model improvement. The outcomes of SWAMI will provide a pathway to improved space weather services as the project will not only address the science issues, but also the transition of models into operational services. The project aims to develop a unique new whole atmosphere model, by extending and blending the Unified Model (UM), which is the Met Office weather and climate model, and the Drag Temperature Model (DTM), which is a semi-empirical model which covers the 120–1500 km altitude range. A user-focused operational tool for satellite applications shall be developed based on this. In addition, improved geomagnetic indices shall be developed and shall be used in the UM and DTM for enhanced nowcast and forecast capability. In this paper, we report on progress with SWAMI to date. The UM has been extended from its original upper boundary of 85 km to run stably and accurately with a 135 km lid. Developments to the UM radiation scheme to enable accurate performance in the mesosphere and lower thermosphere are described. These include addition of non-local thermodynamic equilibrium effects and extension to include the far ultraviolet and extreme ultraviolet. DTM has been re-developed using a more accurate neutral density observation database than has been used in the past. In addition, we describe an algorithm to develop a new version of DTM driven by geomagnetic indices with a 60 minute cadence (denoted Hp60) rather than 3-hourly Kp indices (and corresponding ap indices). The development of the Hp60 index, and the Hp30 and Hp90 indices, which are similar to Hp60 but with 30 minute and 90 minute cadences, respectively, is described, as is the development and testing of neural network and other machine learning methods applied to the forecast of geomagnetic indices.