Preprints
Search for earthquake (578 results)
Directional Peak Factors of Strong-Motion Response Spectra: A Stochastic Field Representation on the Circle
Published: 2026-02-20
Subjects: Civil and Environmental Engineering, Civil Engineering, Engineering, Structural Engineering
Directional variability in horizontal earthquake ground motions is often addressed using orientation-independent intensity measures obtained by rotating the two horizontal components and summarizing the resulting response spectra. In contrast, the stochastic structure of directional peak factors, which connect second-order response measures to extreme response levels, has received limited [...]
Rotation-Invariant Ground-Motion as Directional Selection Operators: A Closed-Form Framework for RotD Response Spectra
Published: 2026-02-20
Subjects: Civil and Environmental Engineering, Civil Engineering, Structural Engineering
Horizontal earthquake ground motion is inherently two-dimensional, yet most engineering applications rely on scalar intensity measures. Rotation-invariant response spectra such as RotD50, MaxRotD50, and RotD100 are widely used to remove dependence on sensor orientation. They are often treated as direction-free scalars, which they are not. In this study, directional pseudo-spectral acceleration is [...]
A preliminary seismic catalog for the Mozambique Channel
Published: 2026-02-12
Subjects: Geophysics and Seismology, Tectonics and Structure
The Mozambique Channel is a 1,600-km long, 950 – 1,000-km wide deep-water arm of southwestern Indian Ocean, located between Mozambique and Madagascar Island. The channel hosts the offshore continuation of the East African Rift System, an active divergent plate boundary that has propagated from the African continent, across Mesozoic continental rifted margins, into Mesozoic oceanic lithosphere. [...]
Evidence of a ULVZ near Vanuatu from Sdiff postcursors
Published: 2026-02-06
Subjects: Geophysics and Seismology
Thin anomalous structures known as ultra-low velocity zones (ULVZs) have been found on the core-mantle boundary (CMB) and have extreme velocity reductions. These features are detected due to their effect on seismic waves that travel through them, typically producing precursors or postcursors. In this study we use postcursors to shear core-diffracted waves (Sdiff+) that sample the CMB near Vanuatu [...]
Elevated in-situ Vp/Vs preceding hydraulic-fracturing-induced earthquakes
Published: 2026-02-04
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Effective management of seismic hazard in geo-energy development demands real-time estimates of subsurface fault instability. However, real-time monitoring of pore pressure change during subsurface fluid injection remains challenging. Here, we present a novel high-resolution, non-tomographic monitoring strategy that tracks the ratio of seismic wave speeds (Vp/Vs) as a proxy for pore pressure [...]
Analyzing volcanic-like earthquakes with distributed acoustic sensing using a short segment of the Tongan seafloor telecommunications cable
Published: 2026-01-30
Subjects: Volcanology
The 2022 Hunga Tonga-Hunga Haʻapai (HTHH) eruption highlighted the need for monitoring submarine volcanoes. Distributed Acoustic Sensing (DAS), utilizing existing seafloor cables offers a promising solution. We analyze a one-week DAS dataset recorded in February 2023, one year after the eruption, using a 30-km segment of the domestic telecommunication cable in Tonga. The previous study (Nakano et [...]
Do 3D Dynamic Rupture Models Capture the Variability in Long-Period Velocity Pulses? Insights from the 2023 Mw 7.8 Kahramanmaraş Earthquake
Published: 2026-01-28
Subjects: Physical Sciences and Mathematics
Capturing ground motion variability, especially in near-fault long-period velocity pulses, is a key challenge for seismic hazard assessment. Empirical methods often rely on simplified assumptions and may not fully capture the non-linear interplay of source, path, and site effects. Physics-based dynamic rupture simulations offer a self-consistent alternative, but their ability to reproduce [...]
Estimation of Near-Surface Density using Vertical Gravity Gradients in Central and Western Japan
Published: 2026-01-22
Subjects: Earth Sciences
The Vertical Gravity Gradient (VGG), derived from the difference between terrestrial and airborne gravity data, highlights shallow density contrasts. We estimated the near-surface density structure of Central and Western Japan using VGGs derived from terrestrial data within 3 km of airborne flight lines. We constructed an inversion model on a 1/7-degree grid to estimate surface density and a [...]
A detailed picture of Haiti’s seismicity given by deep learning and template matching
Published: 2026-01-20
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics
Haiti regularly experiences destructive earthquakes, but seismic monitoring in the region has historically been limited. Recent deployments of citizen-hosted RaspberryShake seismometers and temporary seismic deployment following the 2021 Mw 7.2 earthquake provide new data to study the region’s seismotectonics. However, high noise levels at many stations, in particular the RaspberryShake ones, [...]
The Coupling Cloud: A community database of megathrust kinematic coupling models
Published: 2026-01-14
Subjects: Earth Sciences
Kinematic coupling models inverted from geodetic data are widely used to evaluate how slip deficit is distributed along subduction megathrusts during the interseismic period, and are central to earthquake and tsunami hazard assessment. Yet, existing coupling models differ widely in methodology and inputs, lack common community standards, and are scattered across publications and repositories. [...]
Role of Lithospheric and Upper-Mantle Heterogeneities in Controlling Intraplate Seismicity in Central and Southeastern Brazil
Published: 2026-01-11
Subjects: Earth Sciences, Geology, Geophysics and Seismology
Seismicity in Central and Southeastern Brazil is spatially heterogeneous, with active zones showing little correspondence to major geological provinces, a pattern typical of many intraplate settings worldwide. While previous studies have explored possible controls using geophysical observations, the relative roles of crustal and upper-mantle heterogeneities in shaping the regional stress fields [...]
Modeling Lithospheric Radioactivity Influence on Atmospheric Electric Properties relative to Earthquakes
Published: 2026-01-04
Subjects: Physical Sciences and Mathematics
This study presents a mathematical exploration of the atmospheric electric field components resulting from radon-induced ionization, with implications in the study of earthquake phenomena. By formalizing the general solution to the proposed equations with given boundary conditions, the research offers a comparative analysis of electric parameters across different radon concentrations and radii of [...]
The 1935 Guyana event and the 1908 Tunguska event
Published: 2026-01-03
Subjects: Education, Physical Sciences and Mathematics
This paper is a continuation of a series of works, devoted to various aspects of the 1908 Tunguska event. In 1935 a remarkable event took place in Guyana (at that time British Guiana). A meteor was seen and a large area of devastated forest was discovered. The main source for information on this event was an article published in an astronomical magazine in 1939. The 1939-article provided [...]
Multi-frequency Teleseismic P-wave Back-projection of the 2025 Mw 8.8 Kamchatka Peninsula Earthquake
Published: 2025-12-27
Subjects: Earth Sciences
A great megathrust earthquake with moment magnitude Mw 8.8 struck off the Kamchatka Peninsula on July 29, 2025, generating a Pacific-wide tsunami and rupturing a segment of the Kuril–Kamchatka subduction zone that has repeatedly hosted M9-class earthquakes. We apply multi-frequency teleseismic P-wave back-projection (BP) analysis using six frequency bands spanning 0.003–2.0 Hz to investigate the [...]
Large Earthquakes: a Way of Formation and Prediction
Published: 2025-12-26
Subjects: Geophysics and Seismology, Tectonics and Structure
It is believed that the accumulation of small fractures (small earthquakes) in the crust is one of many ways for the formation of large fractures (large earthquakes). In such cases, the temporal variations in the accumulation number of small earthquakes can be used to predict future seismic activity in the region. To do so, a structural system of the crust is constructed using the logarithmic [...]