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Publication date: 15 February 2025

Source: Earth and Planetary Science Letters, Volume 652

Author(s): Pascal M. Kruttasch, Karen Ziegler, Julian-Christopher Storck, Nicolas D. Greber, Aryavart Anand, Klaus Mezger

Publication date: 15 February 2025

Source: Earth and Planetary Science Letters, Volume 652

Author(s): Qian Liu, Laura F. Robinson, Erica Hendy, Joseph A. Stewart, Tao Li, Tianyu Chen, Timothy D.J. Knowles

Publication date: 15 February 2025

Source: Earth and Planetary Science Letters, Volume 652

Author(s): Mingqing Zhu, Deguo Zhang, Peng Liang, Xiaoping Yang

Publication date: 1 January 2025

Source: Advances in Space Research, Volume 75, Issue 1

Author(s): Lu Liu, Hong Deng, Junwei Luo, Weiwei Wang, Jiafu Liu

Methane from the destroyed Nord Stream pipelines spread over a large part of the southern Baltic Sea and remained for several months. This is according to a study by researchers from the University of Gothenburg and the Voice of the Ocean research foundation.

With the increase in climate change, global precipitation estimates have become a necessity for predicting water-related disasters like floods and droughts, as well as for managing water resources. The most accurate data that can be used for these predictions are ground rain gauge observations, but it is often challenging due to limited locations and sparse rain gauge data.

Earth, being 71% covered in water, is influenced by the ocean and its movements. In the Atlantic Ocean, a system of connected currents, called the Atlantic Meridional Overturning Circulation (AMOC), moves water throughout the world's oceans powered by a combination of winds and ocean density. It not only distributes the ocean's heat, moisture, and nutrients, but regulates the Earth's climate and weather.

As the atmosphere continues to fill with greenhouse gases from human activities, many proposals have surfaced to "geoengineer" climate-saving solutions, that is, alter the atmosphere at a global scale to either reduce the concentrations of carbon or mute its warming effect.

Author(s): A. Curcio, M. L. Berlanga, N. Boudjema, E. Chiadroni, A. Cianchi, A. Del Dotto, D. Francescone, M. Galletti, V. Horny, A. Huerta, A. Mostacci, J. A. Pérez-Hernández, M. Petrarca, I. Rodriguez, C. Salgado-López, F. Stocchi, P. Tomassini, I. Vladisavlevici, M. D. Frias, M. Ferrario, and G. Gatti

The duration of incoherent XUV pulses down to the femtoseconds (fs) can be retrieved through a statistical analysis of the modulations on the observed radiation spectrum. Uncorrelated shot-noise fluctuations in the pulse temporal profile result in incoherent radiation showing a multispike spectrum w…

[Phys. Rev. E 111, L013201] Published Wed Jan 15, 2025

Abstract

This study addresses the frequent convergence issues of satellite clocks within regional network, with a particular focus on the multifrequency advantages using data from 25 uniformly distributed reference stations across China. Experimental results demonstrate that incorporating the third frequency significantly enhances the accuracy of BDS-3 clock solutions, reducing the root mean square (RMS) by 44.5%. Additionally, employing a 2-min smoothing interval, multifrequency inclusion increases the wide-lane (WL) fixing rate by 30.4% at low elevation angles, which in turn leads to a marked improvement in narrow-lane (NL) ambiguity resolution. By leveraging phase-wide-lane observations, the stable wide-lane phase bias enables the continuous generation of inter-frequency clock bias (IFCB), ensuring reliable cyclic sequence construction even when satellites exit the observed region. The effectiveness of regional observable specific bias (OSB) on ambiguity resolution at the user level is highlighted, and over 95% of GPS, BDS-3, and Galileo NL fractional biases below 0.15 cycles could be achieved. Furthermore, the single-epoch convergence rates of multi-constellation precise point positioning (PPP) reach horizontal 91.9% and vertical 84.5% for multifrequency, a substantial improvement over the dual-frequency, which does not exceed 25%.

SummaryThe 1929 Grand Banks earthquake (Mw 7.1) generated a large landslide that broke submarine cables near the source area. A large tsunami was generated by the large landslide that killed 28 people on the southern coast of the Burin Peninsula, Canada. The tsunami was also observed at a tide gauge in Halifax, Canada. In this study, the initial landslide mass distribution was estimated by fitting the first pulse of the tsunami waveform observed at Halifax and the timings of the submarine cable break with those computed values. A deep-sea landslide tsunami computation method was developed by modifying a previously developed Tsunami Squares method with a different friction term and an effect of deep water. The results showed that the tsunami waveform and timing of the cable break were well explained by the tsunami computed from the initial landslide mass volume of about 450 km3 located along the continental slope near the source area. The method developed to compute deep-sea landslide tsunamis should be useful for studying other types of landslide tsunamis.

SummaryWe conduct a comprehensive comparison of Ice Mass Balance (IMB) estimates for Greenland derived from satellite observations of ice Surface Elevation Changes (SEC), gravity and GNSS observations. Our analysis integrates data from the ICESat and CryoSat-2 satellite altimetry missions, augmented by optical stereo-imagery for peripheral glaciers, and GRACE satellite gravimetry mission, spanning the 2003-2008 and 2011-2015 periods. We also consider three firn densification models (FDM) and five Glacial Isostatic Adjustment (GIA) models for correcting the datasets for these effects when necessary. Our results reveal significant differences among FDM corrections applied to SEC observations, with particularly large variations in IMB estimates reaching up to 90 Gt/yr. To address this, we develop an innovative method for estimating equivalent firn corrections to the ice elevation observations, based on a least-squares fit of filtered ice SEC observations to GRACE mass-change estimates. This approach is both simple and independent from climate models assumptions and shows minimal sensitivity to GIA model differences. Using this method, we estimate IMBs for Greenland at -217.6 ± 15.7 Gt/yr for 2003-2008 and -253.2 ± 18.8 Gt/yr for 2011-2015. Importantly, these values indicate an acceleration of the thinning rate, not consistently captured by the IMB estimates inferred from the ice SEC observations corrected by FDMs. Finally, we compute elastic ground deformation induced by ice mass change during 2011-2015, using the four proposed mass-variation distributions and compare the predicted vertical velocities with GNSS observations in Greenland, accounting for all GIA models. While all models are consistent with most of the GNSS-derived uplift rates, they cannot fully explain the observed vertical velocities, especially in the South-East Greenland, which confirms the need to refine our understanding of GIA contributions in this region.

SummaryIn this study, we adopt a horizontally layered model consisting of air, seawater and undersea porous rock and develop an analytically-based method to calculate the seismic and EM fields generated by undersea earthquakes. We conduct numerical simulations to investigate the characteristics of the EM response at the receivers located at the seafloor, in the seawater near the sea surface and in the air, respectively. The results show that two kinds of EM signals can be identified in the EM records at these receivers, namely, the early EM wave (seismic-to-EM conversion at the seafloor interface) arriving before the seismic waves and the coseismic EM fields with apparent speeds of the seismic waves. The EM signals observed at the seafloor are mostly stronger than those observed in the seawater and air near the sea surface. The method is applied to simulating the EM response to the 2022 Mw 7.3 earthquake that took place in the sea near Fukushima, Japan. At a receiver with 76 km epicentral distance at the seafloor, the predicted coseismic electric and magnetic signals reach 2 μV/m and 2 nT, respectively, which are within the detectability of the current EM equipment. This suggest a possibility to monitor the EM disturbances associated with undersea earthquakes and use them to serve the earthquake early warning, helping to mitigate the societal impact of large earthquakes.

Nature Geoscience, Published online: 15 January 2025; doi:10.1038/s41561-025-01641-3

Author Correction: An ongoing satellite–ring cycle of Mars and the origins of Phobos and Deimos

Nature Geoscience, Published online: 15 January 2025; doi:10.1038/s41561-024-01626-8

Photochemical modelling suggests that H2 outgassing from crustal hydration could have supported transient warming episodes on early Mars in a CO2-rich atmosphere with abrupt transitions to cold climate states in a CO-rich atmosphere.

A hidden world teeming with life lies below beach sands. New Stanford-led research sheds light on how microbial communities in coastal groundwater respond to infiltrating seawater.

New research has tracked the evolution of a glacier lake dammed by a glacier surge using satellite images, to help better understand its life cycle and the hazard it presents to nearby communities.

Author(s): M. W. C. Dharma-wardana, Dennis D. Klug, Hannah Poole, and G. Gregori

Recent cutting-edge experiments have provided in situ structure characterization and measurements of the pressure (P), density (ρ¯), and temperature (T) of shock compressed silicon in the 100 GPa range of pressures and up to ∼10000K. We present first-principles calculations in this P,T,ρ¯ regime to …

[Phys. Rev. E 111, 015205] Published Tue Jan 14, 2025

Nature Geoscience, Published online: 14 January 2025; doi:10.1038/s41561-024-01624-w

Near-daily sampling of volcanic ash during a three-month eruption reveals shifts in mantle-derived liquid magma (melt) composition, highlighting its potential as a monitoring and forecasting tool. These shifts align with the amplitude of volcanic tremor, a persistent seismic signal, suggesting a link between magma viscosity, shallow bubble escape dynamics, and tremor changes.

SummaryLow-frequency laboratory measurements provide direct access to the elastic properties of samples within the seismic frequency band, offering calibration data for seismic survey analysis. Additionally, µCT imaging can quantify actual saturations and provides insights into phase distributions at the pore scale. To conduct laboratory triaxial measurements at seismic frequencies while simultaneously imaging the rock interior, we developed an X-ray transparent low-frequency apparatus. Our apparatus determines rock mechanical properties at seismic frequencies (0.5–150 Hz) and strain amplitudes (10−7–10−5), measuring Young’s modulus, Poisson’s ratio, and attenuation. In addition P- and S-wave velocities at ultrasonic frequencies are measured. We conducted imbibition-drainage experiments to assess the effect of saturation and patch size on seismic and ultrasonic elastic properties in sandstone. Additional tests with liquid and gaseous CO2 reveal the impact of partial CO2-gas saturation. The imbibition-drainage experiment demonstrated that P-wave velocity at ultrasonic frequencies was elevated during drainage and reduced during imbibition. Drainage caused patchy saturation, while imbibition resulted in uniform saturation. This implies that ultrasonic measurements, with wavelengths comparable to the pore fluid patch size, are likely influenced by scattering. In contrast, low-frequency measurements, where the wavelength surpasses the patch size, capture effective medium properties and therefore are not affected by scattering effects. The results of the CO2 test suggest that low-frequency measurements can detect even low gas saturations (4% gaseous CO2). In contrast, ultrasonic velocity measurements primarily reflect the response of the fully saturated sample at low gas saturations and do not indicate a reduction in velocity. Identifying fluid-solid interactions and estimating saturation via µCT imaging is crucial, especially with minimal gas presence. Our combined approach allows precise determination of elastic properties at seismic frequencies and shows the importance of low-frequency over ultrasonic measurements.