Article
Geosciences, Multidisciplinary
Pablo Urra-Tapia, Diego Gonzalez-Vidal, Matthew Miller, Jose Luis Palma
Summary: We conducted the first ambient noise tomography of Villarrica Volcano and obtained a 3D shear-wave velocity model. Using ambient noise from 18 seismic stations recorded between May and July 2014, we measured the Rayleigh wave group velocity by cross-correlating station pairs. The resulting group velocity curves were used to create 2D tomographic maps, which were then locally inverted to obtain an accurate Vs model in depth. Our study revealed velocity variations within the volcano region, reaching a depth of approximately 7.5 km. The resulting 3D shear-wave velocity model provided new insights into the internal structure of the area, including slow velocity anomalies along the volcanic lineament and a negative velocity anomaly southeast of the Villarrica summit, consistent with the proposed magmatic plumbing system.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2023)
Article
Geochemistry & Geophysics
Victor C. Tsai, Korbinian Sager
Summary: This study demonstrates the use of Bayesian inference approach in calculating the expected cross correlation of seismic signals, leading to a better understanding of its relationship with the Green's function. The Bayesian derivation replicates the equipartition result, and with stronger constraints, deviation from the expected Green's function is observed, allowing for more reliable comparison with observations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Mario Z. Ruiz, Francesco Civilini, Cynthia J. Ebinger, Sarah J. Oliva, Mario C. Ruiz, Gabriela Badi, Peter C. La Femina, Jose A. Casas
Summary: Analyzing the changes in physical properties before a volcanic eruption, we identified potential premonitory signals. In particular, we observed a 0.27% decrease in velocity 17 days before the eruption at stations located beneath the north-eastern sector of the volcano. This velocity change may be attributed to dilation caused by an earthquake and degassing of fluids in the rock.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Engineering, Multidisciplinary
Shaohong Xia, Changrong Zhang, Jinghe Cao
Summary: In this study, based on the data recorded by a dense array on an isolated coral island in the South China Sea, we analyzed the ambient noise characteristics and obtained a 3D subsurface structure of the coral island using ambient noise tomography. Our research demonstrates the potential of ambient noise tomography as an economical, efficient, and environmentally friendly method for the geological prospecting of coral reefs.
Article
Multidisciplinary Sciences
Ivan Cabrera-Perez, Jean Soubestre, Luca D'Auria, Jose Barrancos, Alba Martin-Lorenzo, David Martinez van Dorth, German D. Padilla, Monika Przeor, Nemesio M. Perez
Summary: By using Ambient Noise Tomography (ANT), we have successfully constructed a high-resolution seismic velocity model of the first few kilometers of the crust of La Palma island and merged it with a recent local earthquake tomography model. Our findings reveal high-velocity zones in the northern and southern parts of the island, possibly related to plutonic intrusion and old oceanic crust materials. Four low-velocity zones are imaged in the southern part, two of which may be associated with hydrothermal alteration zones beneath the Cumbre Vieja volcanic complex. The comparison of the S-wave velocity model with seismicity recorded during the pre-eruptive phase of the 2021 Tajogaite eruption supports this hypothesis.
SCIENTIFIC REPORTS
(2023)
Article
Geosciences, Multidisciplinary
Raphael S. M. De Plaen, Aurelien Mordret, Raul Arambula-Mendoza, Dulce Vargas-Bracamontes, Victor Hugo Marquez-Ramirez, Thomas Lecocq, Carlos Ariel Ramirez Vazquez, Miguel Gonzalez Amezcua
Summary: In this study, the researchers used high-resolution shear-wave velocity tomography to investigate the internal structure of Volcan de Colima. The results revealed a network of low-velocity anomalies, indicating the potential connection to the volcanic activity history and magma transportation.
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
(2022)
Article
Environmental Sciences
Niels Grobbe, Aurelien Mordret, Stephanie Barde-Cabusson, Lucas Ellison, Mackenzie Lach, Young-Ho Seo, Taylor Viti, Lauren Ward, Haozhe Zhang
Summary: A watershed on the Kaiwi Coast in Hawaii was studied using a combination of ANSWT and SP measurements to investigate groundwater systems. The joint interpretation of SP and seismic data revealed the distribution of groundwater, geological structures, and flow patterns in the region. This innovative methodology showcased the effectiveness of using multiple hydrogeophysical techniques for comprehensive groundwater studies.
WATER RESOURCES RESEARCH
(2021)
Article
Geochemistry & Geophysics
C. Alder, E. Debayle, T. Bodin, A. Paul, L. Stehly, H. Pedersen
Summary: Studying seismic anisotropy in the lithosphere has revealed significant radial anisotropy beneath the Apennines in Europe, differing from previous large-scale studies. This radial anisotropy is attributed to ductile horizontal flow in response to recent and present-day extension in the region.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
XiaoZhuo Wei, Yang Shen, Julia K. K. Morgan
Summary: This study used seismic ambient noise to obtain empirical Green Functions (EGFs) and empirical Green Tensors (EGTs), which contained different modes of Rayleigh waves. By measuring the group velocities of these modes and inverting for group arrival times, two-dimensional group velocity maps and a three-dimensional shear wave velocity model were obtained. These results provide new insights into the structure and growth of the volcanoes on the Island of Hawaii.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Multidisciplinary Sciences
Leiming Zheng, Xiaoping Fan, Peng Zhang, Jingrun Hao, Hao Qian, Tuo Zheng
Summary: This study utilized group-velocity ambient noise tomography to detect and study the structure of the Mufushan-Jiaoshan fault in Zhenjiang area, China. The results showed different characteristics of shear-wave velocity at different depths along the fault, with the gradient zone potentially indicating the location of the main fracture surface.
SCIENTIFIC REPORTS
(2021)
Article
Geosciences, Multidisciplinary
Yesim Cubuk-Sabuncu, Kristin Jonsdottir, Corentin Caudron, Thomas Lecocq, Michelle Maree Parks, Halldor Geirsson, Aurelien Mordret
Summary: Repeated periods of inflation-deflation were detected near Mt. thorn orbjorn-Svartsengi in SW-Iceland from January to July 2020. Seismic ambient noise and interferometry were used to characterize the temporal variations of seismic velocities. The largest velocity drop was observed at the seismic station closest to the inflation source center, and the dv/v variations correlated with deformation measurements over the unrest period, indicating sensitivity to crustal processes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Lise Retailleau, Gregory C. Beroza
Summary: Correlations of the ambient seismic field recorded by seismic stations provide information about wave propagation and sources of scattering. By analyzing correlation functions, sources of signals linked to scattering can be located.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Zhi Guo, Xing Gao
Summary: In this study, the isotropic and azimuthal anisotropic crustal structure of the South China block is imaged using continuous seismic ambient noise recorded by dense permanent seismic stations. The results show the lateral changes in the isotropic crustal structure are consistent with surface geology, while the azimuthal anisotropy reveals more details about the tectonic evolution of the South China block.
Article
Geosciences, Multidisciplinary
J. P. O'Donnell, S. Agrawal, C. M. Eakin, S. Thiel, K. Brand, A. Gorbatov, B. Goleby
Summary: The rocks of southern Australia, veiled by sediment, have recorded over three billion years of Earth's evolution. Geophysical data, including seismic arrays, have been used to uncover the geological structures, resulting in the development of velocity models and the identification of key features such as fault boundaries and low velocity zones. These findings provide insights into the geological history and potential mineral deposits in the region.
Article
Geochemistry & Geophysics
Fabrizio Magrini, Lapo Boschi
Summary: This study evaluates the determination of surface-wave attenuation from ambient-noise data through numerical tests. The directionality of noise sources and the attenuation coefficient in the area of interest were identified from both experimental setups and real recordings. The method shows promise in accurately quantifying surface-wave attenuation at relatively high frequencies.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)