Solid Earth最新文献

{"title":"Rare earth element resources on Fuerteventura, Canary Islands, Spain: a geochemical and mineralogical approach","authors":"Marc Campeny, Inmaculada Menéndez, Luis Quevedo, Jorge Yepes, Ramón Casillas, Agustina Ahijado, Jorge Méndez-Ramos, José Mangas","doi":"10.5194/egusphere-2024-183","DOIUrl":"https://doi.org/10.5194/egusphere-2024-183","url":null,"abstract":"<strong>Abstract.</strong> Rare earth elements (REEs) play a pivotal role in the ongoing energy and mobility transition challenges. Given their critical importance, governments worldwide and especially from the European Union, are actively promoting the exploration of REE resources. In this context, alkaline magmatic rocks (including trachytes, phonolites, syenites, melteigites and ijolites), carbonatites and their associated weathering products were subjected to a preliminary evaluation as potential targets for REE exploration on Fuerteventura Island (Canary Archipelago, Spain) based on mineralogical and geochemical studies. These lithologies show significant REE concentrations. However, only carbonatites exhibit the potential to host economically viable REE mineral deposits. REE concentrations in carbonatites of up to 10,301.83 ppm REY (REEs plus yttrium) have been detected, comparable to other locations hosting significant deposits of these critical elements worldwide. Conversely, alkaline magmatic rocks and the resulting weathering products display limited REE enrichment. Notably, REEs in carbonatites are associated with primary accessory phases such as REE-bearing pyrochlore and britholite, and secondary monazite. The carbonatites of Fuerteventura hold promise as prospective REE deposits within a non-conventional geological setting (oceanic island). However, due to intricate structural attributes and possible land use constraints, additional future detailed investigations are imperative to ascertain their genuine economic viability as substantial REE resources.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Earthquakes triggered by the subsurface undrained response to reservoir-impoundment at Irapé, Brazil","authors":"Haris Raza, George Sand França, Eveline Sayão, Victor Vilarrasa","doi":"10.5194/egusphere-2024-166","DOIUrl":"https://doi.org/10.5194/egusphere-2024-166","url":null,"abstract":"<strong>Abstract.</strong> The necessity to reduce carbon emissions to mitigate climate change is accelerating the transition from fossil fuels to renewable energy sources. Specifically, hydropower, in particular, has emerged as a prominent and safe renewable energy source but entails reservoir-triggered seismicity (RTS). This phenomenon causes significant challenges for safe reservoir management. Irapé, in Brazil, is a prominent RTS site where seismicity surged after reservoir filling, with a maximum event of magnitude 3.0 in May 2006, just six months after the start of reservoir impoundment. Despite more than a decade has passed since the seismicity occurred, the factors governing these earthquakes and their connection to subsurface rock properties remain poorly understood. Here, we attempt to understand the potential causes of RTS at Irapé dam, which is the highest dam in Brazil with 208 m, and the second highest in South America. Permeability and porosity measurements of cylindrical cores from hard and intact rock samples, which have been extracted near the RTS zone, by pitting 10 cm from the surface, reveal a low-permeability rock. Porosity values range from 6.340 to 14.734 %. Only 3 out of the 11 tested samples present permeability higher than the lowest measurable value of the apparatus (0.002 mD), with the highest permeability being 0.0098 mD. The undrained response of the low-permeability rock placed below the reservoir results in an instantaneous increase in pore pressure and poroelastic stress changes due to elastic compression, which brings potential faults located below the reservoir closer to failure conditions. According to our analytical calculations, the increase in 136 m of the reservoir-water level caused a 0.54 MPa pore pressure buildup at the depth of the Magnitude 3.0 earthquake, i.e., 3.88 km, resulting in an increase of 0.82 MPa in the vertical effective stress and a decrease of 0.34 MPa in the horizontal effective stress. These changes resulted in an increase in the deviatoric stress that led to fault destabilization, causing the RTS. The laboratory measurements and analytical calculations corroborate the hypothesis that the initial seismic activity was induced by the undrained subsurface response to the reservoir loading at Irapé.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140005482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Increased metamorphic conditions in the lower crust during oceanic transform fault evolution","authors":"Peter Haas, Myron F. H. Thomas, Christian Heine, Jörg Ebbing, Andrey Seregin, Jimmy van Itterbeeck","doi":"10.5194/egusphere-2024-425","DOIUrl":"https://doi.org/10.5194/egusphere-2024-425","url":null,"abstract":"<strong>Abstract.</strong> Oceanic transform faults connect the segments of active spreading ridges that slide past each other. In a classical view, transform faults are considered as conservative, where no material is added or destroyed. Recent studies, however, suggest that the crust in the transform fault region is deformed during different episodes. We combine high resolution 3D broadband seismic data with shipborne potential field data to study ancient fault zones in Albian-Aptian aged oceanic crust in the eastern Gulf of Guinea offshore S<span>ã</span>o Tomé and Príncipe. The crust in this region is characterized by a thin, high-reflective upper crust, which is underlain by a thick, almost seismically transparent unit that comprises localized dipping reflectors, previously interpreted as extrusive lava flows. This layer defines the target area for inversion and forward modelling of the potential field data. The picked seismic horizons are used as geometrical boundaries of the crustal model. First, we perform a lateral parameter inversion for the lower crust, which provides vertical columns of density and magnetic susceptibility. Second, we sort the estimated values using a clustering approach and identify five groups with common parameter relationships. Third, we use the clustered lower crustal domains to define a consistent 3D model of the study area that aligns with the seismic structure and geological concepts, preferred to the simple inversion of the first step. The final model shows anomalous low susceptibility and medium to high density close to the buried fracture zones, which reflects increasing pressure and temperature conditions accompanied by a change of metamorphic facies. Our model indicates enhanced tectonic activity with an extensional component during the formation of oceanic crust that culminates in the transform region. These results are in line with recent studies and strengthen the impressions of a non-conservative character of ridge-transform intersections.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139980781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combining crosshole and reflection borehole-GPR for imaging controlled freezing in shallow aquifers","authors":"Peter Jung, Götz Hornbruch, Andreas Dahmke, Peter Dietrich, Ulrike Werban","doi":"10.5194/egusphere-2024-257","DOIUrl":"https://doi.org/10.5194/egusphere-2024-257","url":null,"abstract":"<strong>Abstract.</strong> During test operation of a geological latent heat storage system as a potential option in the context of heat supply for heating and cooling demands a part of a shallow quaternary glacial aquifer at the “TestUM” test site is frozen. To evaluate the current thermal state in the subsurface the dimension of the frozen volume has to be known. With the target being too deep for high resolution imaging from the surface, the use of borehole Ground-Penetrating-Radar (GPR) is assessed. For imaging and monitoring of a vertical freeze-thaw boundary, crosshole zero-offset and reflection measurements are applied. The freezing can be imaged in ZOP, but determination of ice body size is ambiguous, because of lacking velocity information in the frozen sediment. Reflection measurements are able to image the position of the freezing boundary with an accuracy determined through repeated measurements of ±0.1 <em>m</em>, relying on the velocity information from ZOP. We found, that the complementary use of ZOP and reflection measurements make for a fast and simple method, to image freezing in geological latent heat storage systems. Problematic is the presence of superimposed reflections from other observation wells and low signal-to-noise ratio. The use in multiple observation wells allows for an estimation of ice body size. A velocity model derived from zero-offset profiles (ZOP) enabled to extrapolate geological information from direct-push based logging and sediment cores to a 3D-subsurface model.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139980630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highlights on mantle deformation beneath the Western Alps with seismic anisotropy using CIFALPS2 data","authors":"Silvia Pondrelli, Simone Salimbeni, Judith M. Confal, Marco Malusà, Anne Paul, Stephane Guillot, Stefano Solarino, Elena Eva, Coralie Aubert, Liang Zhao","doi":"10.5194/egusphere-2024-468","DOIUrl":"https://doi.org/10.5194/egusphere-2024-468","url":null,"abstract":"<strong>Abstract.</strong> There are still open questions about the deep structure beneath the Western Alps. Seismic velocity tomographies show the European slab subducting beneath the Adria plate, but all these images did not clarify completely about the possible presence of tears, slab windows or detachments. Seismic anisotropy, addressed as an indicator of mantle deformation and studied using data recorded by dense networks, may shed some light about the location and orientation of mantle flow at depth. Using the large amount of shear wave splitting and splitting intensity measurements available in the Western Alps, collected through the CIFALPS2 temporary seismic network, together with already available data, highlight some new patterns, filling the gaps left by previous studies. Instead of the typical seismic anisotropy pattern parallel to the entire arc of the Western Alps, this study supports the presence of a differential contribution along the belt, only partly related to the European slab retreat. A nearly NS anisotropy pattern beneath the external Alps, direction that cuts the morphological features of the belt, is clearly found with the new CIFALPS2 measurements. It is however confirmed that the asthenospheric flow from Central France toward the Tyrrhenian Sea, is turning around the southern tip of the European slab.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139921242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of faults on the remote stress state","authors":"Karsten Reiter, Oliver Heidbach, Moritz O. Ziegler","doi":"10.5194/se-15-305-2024","DOIUrl":"https://doi.org/10.5194/se-15-305-2024","url":null,"abstract":"Abstract. The impact of faults on the contemporary stress field in the upper crust has been discussed in various studies. Data and models clearly show that there is an effect, but so far, a systematic study quantifying the impact as a function of distance from the fault is lacking. In the absence of data, here we use a series of generic 3-D models to investigate which component of the stress tensor is affected at which distance from the fault. Our study concentrates on the far field, located hundreds of metres from the fault zone. The models assess various techniques to represent faults, different material properties, different boundary conditions, variable orientation, and the fault's size. The study findings indicate that most of the factors tested do not have an influence on either the stress tensor orientation or principal stress magnitudes in the far field beyond 1000 m from the fault. Only in the case of oblique faults with a low static friction coefficient of μ=0.1 can noteworthy stress perturbations be seen up to 2000 m from the fault. However, the changes that we detected are generally small and of the order of lateral stress variability due to rock property variability. Furthermore, only in the first hundreds of metres to the fault are variations large enough to be theoretically detected by borehole-based stress data when considering their inherent uncertainties. This finding agrees with robust stress magnitude measurements and stress orientation data. Thus, in areas where high-quality and high-resolution data show gradual and continuous stress tensor rotations of >20∘ observed over lateral spatial scales of 10 km or more, we infer that these rotations cannot be attributed to faults. We hypothesize that most stress orientation changes attributed to faults may originate from different sources such as density and strength contrasts.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139945535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal structure of the southern Caribbean and northwestern South America: implications for seismogenesis","authors":"Ángela María Gómez-García, Álvaro González, Mauro Cacace, Magdalena Scheck-Wenderoth, Gaspar Monsalve","doi":"10.5194/se-15-281-2024","DOIUrl":"https://doi.org/10.5194/se-15-281-2024","url":null,"abstract":"Abstract. The seismogenesis of rocks is mainly affected by their mineral composition and in situ conditions (temperature and state of stress). Diverse laboratory experiments have explored the frictional behaviour of the rocks and rock-forming minerals most common in the crust and uppermost mantle. However, it is debated how to “upscale” these results to the lithosphere. In particular, most earthquakes in the crust nucleate down to the crustal seismogenic depth (CSD), which is a proxy for the maximum depth of crustal earthquake ruptures in seismic hazard assessments. In this study we propose a workflow to upscale and validate those laboratory experiments to natural geological conditions relevant for crustal and upper-mantle rocks. We used the southern Caribbean and northwestern South America as a case study to explore the three-dimensional spatial variation of the CSD (mapped as D90, the 90 % percentile of hypocentral depths) and the temperatures at which crustal earthquakes likely occur. A 3D steady-state thermal field was computed for the region with a finite-element scheme using the software GOLEM, considering the uppermost 75 km of a previously published 3D data-integrative lithospheric configuration, lithology-constrained thermal parameters, and appropriate upper and lower boundary conditions. The model was validated using additional, independent measurements of downhole temperatures and heat flow. We found that the majority of crustal earthquakes nucleate at temperatures less than 350 ∘C, in agreement with frictional experiments of typical crustal rocks. A few outliers with larger hypocentral temperatures evidence nucleation conditions consistent with the seismogenic window of olivine-rich rocks, and can be due to either uncertainties in the Moho depths and/or in the earthquake hypocentres or the presence of ultramafic rocks within different crustal blocks and allochthonous terranes accreted to this complex margin. Moreover, the spatial distribution of crustal seismicity in the region correlates with the geothermal gradient, with no crustal earthquakes occurring in domains with low thermal gradient. Finally, we find that the largest earthquake recorded in the region (Mw=7.1, Murindó sequence, in 1992) nucleated close to the CSD, highlighting the importance of considering this lower-stability transition for seismogenesis when characterizing the depth of seismogenic sources in hazard assessments. The approach presented in this study goes beyond a statistical approach in that the local heterogeneity of physical properties is considered in our simulations and additionally validated by the observed depth distribution of earthquakes. The coherence of the calculated hypocentral temperatures with those expected from laboratory measurements provides additional support to our modelling workflow. This approach can be applied to other tectonic settings worldwide, and it could be further refined as new, high-quality hypocentral locations and heat flow an","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Naturally fractured reservoir characterization in heterogeneous sandstones: insight for Uranium In Situ Recovery (Imouraren, Niger)","authors":"Maxime Jamet, Gregory Ballas, Roger Soliva, Olivier Gerbeaud, Thierry Lefebvre, Christine Leredde, Didier Loggia","doi":"10.5194/egusphere-2024-435","DOIUrl":"https://doi.org/10.5194/egusphere-2024-435","url":null,"abstract":"<strong>Abstract.</strong> This study delves into the characterization of a complex reservoir, the Tchirezrine II sandstone unit in North Niger, crucial for potential Uranium In Situ Recovery (ISR) in a naturally fractured and faulted context. Employing a multifaceted approach, including well log data, optical borehole imagery, and hydrogeological tests, alongside satellite-based lineament analysis, this study provides a comprehensive understanding of the structures and its impact on fluid flow. Lineament analysis reveals scale-dependent patterns, consistent with spatially homogeneous joint networks restricted to mechanical units, as well as nearly scale-invariant patterns, better corresponding to spatially heterogeneous fault networks. Various deformation structures are detected from borehole imagery, including Mode I fractures, cataclastic deformation bands, and brecciated-cataclastic fault cores. The Tchirezrine II reservoir displays heterogeneous porosity and permeability related to its fluviatile sedimentary context. These data differ from traditional porosity-permeability relationship obtained in sandstone reservoir matrix but are instead consistent with Nelson’s classification, emphasizing the impact of deformation structures on such petrophysical properties. Hydrological tests have been implemented into a zone of E-W trending deformation structures, revealing a strong permeability anisotropy of this heterogeneity. This strong E-W anisotropy is consistent with the presence of the observed E-W structures, i.e. with a drain behaviour of Mode I open fractures and a sealing behaviour of both cataclastic bands and fault rocks. Considering implications for ISR mining, this study allows discussing the interplay between fractures, faults, and fluid flow properties. It suggests that a well pattern perpendicular to the main permeability orientation can attenuate channelled flow, thus improving contact of the leach solution with the mineralized matrix. These results provide an integrated approach and multi-scale characterization of Naturally<strong> </strong>Fractured Reservoir (NFR) properties in sandstone, offering a basis for optimization of NFR production such as ISR development.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linked and fully coupled 3D earthquake dynamic rupture and tsunami modeling for the Húsavík–Flatey Fault Zone in North Iceland","authors":"Fabian Kutschera, Alice-Agnes Gabriel, Sara Aniko Wirp, Bo Li, Thomas Ulrich, Claudia Abril, Benedikt Halldórsson","doi":"10.5194/se-15-251-2024","DOIUrl":"https://doi.org/10.5194/se-15-251-2024","url":null,"abstract":"Abstract. Tsunamigenic earthquakes pose considerable risks, both economically and socially, yet earthquake and tsunami hazard assessments are typically conducted separately. Earthquakes associated with unexpected tsunamis, such as the 2018 Mw 7.5 strike-slip Sulawesi earthquake, emphasize the need to study the tsunami potential of active submarine faults in different tectonic settings. Here, we investigate physics-based scenarios combining simulations of 3D earthquake dynamic rupture and seismic wave propagation with tsunami generation and propagation. We present time-dependent modeling of one-way linked and 3D fully coupled earthquakes and tsunamis for the ∼ 100 km long Húsavík–Flatey Fault Zone (HFFZ) in North Iceland. Our analysis shows that the HFFZ has the potential to generate sizable tsunamis. The six dynamic rupture models sourcing our tsunami scenarios vary regarding hypocenter location, spatiotemporal evolution, fault slip, and fault structure complexity but coincide with historical earthquake magnitudes. Earthquake dynamic rupture scenarios on a less segmented fault system, particularly with a hypocenter location in the eastern part of the fault system, have a larger potential for local tsunami generation. Here, dynamically evolving large shallow fault slip (∼ 8 m), near-surface rake rotation (± 20∘), and significant coseismic vertical displacements of the local bathymetry (± 1 m) facilitate strike-slip faulting tsunami generation. We model tsunami crest to trough differences (total wave heights) of up to ∼ 0.9 m near the town Ólafsfjörður. In contrast, none of our scenarios endanger the town of Akureyri, which is shielded by multiple reflections within the narrow Eyjafjörður bay and by Hrísey island. We compare the modeled one-way linked tsunami waveforms with simulation results using a 3D fully coupled approach. We find good agreement in the tsunami arrival times and location of maximum tsunami heights. While seismic waves result in transient motions of the sea surface and affect the ocean response, they do not appear to contribute to tsunami generation. However, complex source effects arise in the fully coupled simulations, such as tsunami dispersion effects and the complex superposition of seismic and acoustic waves within the shallow continental shelf of North Iceland. We find that the vertical velocity amplitudes of near-source acoustic waves are unexpectedly high – larger than those corresponding to the actual tsunami – which may serve as a rapid indicator of surface dynamic rupture. Our results have important implications for understanding the tsunamigenic potential of strike-slip fault systems worldwide and the coseismic acoustic wave excitation during tsunami generation and may help to inform future tsunami early warning systems.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global seismic energy scaling relationships based on the type of faulting","authors":"Quetzalcoatl Rodríguez-Pérez, F. Ramón Zúñiga","doi":"10.5194/se-15-229-2024","DOIUrl":"https://doi.org/10.5194/se-15-229-2024","url":null,"abstract":"Abstract. We derived scaling relationships for different seismic energy metrics for earthquakes around the globe with MW > 6.0 from 1990 to 2022. The seismic energy estimations were derived with two methodologies, the first based on the velocity flux integration and the second based on finite-fault models. In the first case, we analyzed 3331 reported seismic energies derived by integrating far-field waveforms. In the latter methodology, we used the total moment rate functions and the approximation of the overdamped dynamics to quantify seismic energy from 231 finite-fault models (Emrt and EO, EU, respectively). Both methodologies provide compatible energy estimates. The radiated seismic energies estimated from the slip models and integration of velocity records are also compared for different types of focal mechanisms (R, reverse; R-SS, reverse–strike-slip; SS, strike-slip; SS-R, strike-slip–reverse; SS-N, strike-slip–normal; N, normal; and N-SS, normal–strike-slip), and then used to derive converting scaling relations among the different energy types. Additionally, the behavior of radiated seismic energy (ER), energy-to-moment ratio (ER/M0), and apparent stress (τα) for different rupture types at a global scale is examined by considering depth variations in mechanical properties, such as seismic velocities, rock densities, and rigidities. For this purpose, we used a 1-D global velocity model. The ER/M0 ratio is, based on statistical t tests, largest for strike-slip earthquakes, followed by normal-faulting events, with the lowest values for reverse earthquakes for hypocentral depths < 90 km. Not enough data are available for statistical tests at deeper intervals except for the 90 to 120 km range, where we can satisfactorily conclude that ER/M0 for R-SS and SS-R types is larger than for N-type faulting, which also conforms to the previous assumption. In agreement with previous studies, our results exhibit a robust variation in τα with the focal mechanism. Regarding the behavior of τα with depth, our results agree with the existence of a bimodal distribution with two depth intervals where the apparent stress is maximum for normal-faulting earthquakes. At depths in the range of 180–240 km, τα for reverse earthquakes is higher than for normal-faulting events. We find the trend EU > Emrt > EO for all mechanism types based on statistical t tests. Finite-fault energy estimations also support focal mechanism dependence of apparent stress but only for shallow earthquakes (Z < 30 km). The slip distribution population used was too small to conclude that finite-fault energy estimations support the dependence of average apparent stress on rupture type at different depth intervals.","PeriodicalId":21912,"journal":{"name":"Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.4,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139769853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}