E. Shalev

Duke University

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P. E. Malin

Applied Spectral Imaging (United States)

B. Voight

Pennsylvania State University

G. S. Mattioli

The University of Texas at Arlington

D. Hidayat

Politeknik STMI Jakarta

A. T. Linde

Carnegie Institution for Science

R. S. J. Sparks

University of Bristol

Derek Elsworth

Pennsylvania State University

Christina Widiwijayanti

Earth Observatory of Singapore

M. Paulatto

Imperial College London

T. A. Minshull

National Oceanography Centre

Cooperative Institutions

United States Geological Survey

Montserrat Volcano Observatory

Pennsylvania State University

University of Cambridge

University of Bristol

Duke University

University of Auckland

Stanford University

University of Oxford

California Institute of Technology

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On the stability of P-wave tomography at Loma Prieta: A comparison of parameterizations, linear and nonlinear inversions

Bulletin of the Seismological Society of America (1992)

Jonathan M. Lees E. Shalev

We investigate the stability of tomographic analysis by comparing the results of two different methods of parameterizing the three-dimensional P -wave velocity variations in the vicinity of the 1989 Loma Prieta earthquake. A block inversion is implemented using 55 by 45 by 10 blocks of 1 km width and varying thickness to a depth of 25 km below the surface. Linear and nonlinear analysis are presented. The nonlinear analysis is achieved by iterating over three-dimensional raytracing and earthquake relocation relative to current three-dimensional models until solutions show only small improvements. A second parameterization is achieved by using cubic B-spline functions to span the space of the model, which is rotated by 46.5°. Nonlinear results are presented with several different starting models illustrating the robustness of the technique to the initial conditions. All the nonlinear results produced essentially the same final model, which was structurally the same as the model obtained by linear analysis using a reasonable starting model.

Nonlinear model

10.1785/bssa0820041821

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Citations (21)

Prototype PBO instrumentation of CALIPSO project captures world‐record lava dome collapse on Montserrat Volcano

Eos (2004)

G. S. Mattioli S. R. Young B. Voight R. Steven J. Sparks

This article is an update on the status of an innovative new project designed to enhance generally our understanding of andesitic volcano eruption dynamics and, specifically the monitoring and scientific infrastructure at the active Soufrière Hills Volcano (SHV), Montserrat. The project has been designated as the Caribbean Andesite Lava Island Precision Seismo‐geodetic Observatory known as CALIPSO. Its purpose is to investigate the dynamics of the entire SHV magmatic system using an integrated array of specialized instruments in four strategically located ∼200‐m‐deep boreholes in concert with several shallower holes and surface sites. The project is unique, as it represents the first, and only such borehole volcano‐monitoring array deployed at an andesitic stratovolcano.

Stratovolcano

Lava dome

10.1029/2004eo340001

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Citations (26)

Observing the San Andreas Fault at Depth

AGUFM (2005)

William L. Ellsworth Stephen H. Hickman Mark D. Zoback Earl Davis L. S. Gee

Source

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Citations (6)

Pyroclastic Flow Generated Tsunami Waves Detected by CALIPSO Borehole Strainmeters at Soufriere Hills, Montserrat During Massive Dome Collapse: Numerical Simulations and Observations

AGUFM (2004)

E. J. van Boskirk B. Voight P. Watts Christina Widiwijayanti G. S. Mattioli

Dome (geology)

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Citations (1)

San Andreas Fault Branching at SAFOD From Fault Guided Wave Mapping and P-wave Tomography

AGU Fall Meeting Abstracts (2005)

P. E. Malin E. Shalev

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Citations (0)

Upper crustal structure of an active volcano from refraction/reflection tomography, Montserrat, Lesser Antilles

Geophysical Journal International (2009)

M. Paulatto T. A. Minshull Brian Baptie S. M. Dean J. O. S. Hammond

To better understand the volcanic phenomena acting on Montserrat, the SEA-CALIPSO seismic experiment (Seismic Experiment with Airgun-source – Caribbean Andesitic Lava Island Precision Seismo-geodetic Observatory) was conducted in 2007 December with the aim of imaging the upper crust and the magmatic system feeding the active Soufriére Hills Volcano. The 3-D survey covered an area of about 50 × 40 km and involved the deployment of 247 land stations and ocean-bottom seismometers (OBSs). A subset of the data, recorded by four OBSs and four land stations on a southeast to northwest line, has been analysed, and traveltimes have been inverted to obtain a 2-D seismic velocity model through the island. Inverted phases include crustal and sediment P waves and wide-angle reflections. The resulting velocity model reveals the presence of a high velocity body (3.5–5.5 km s-1) beneath the island, with highest velocities beneath the Soufriére and Centre Hills, corresponding primarily to the cores of these volcanic edifices, built of a pile of andesite lava domes and subsequent intrusions. In the offshore region, velocities in the surficial sediment layer vary from 1.5 to 3.0 km s-1, consistent with a mainly calcareous and volcaniclastic composition. A wide-angle reflector is observed at a depth of ∼1200 m below the seabed, and appears to deepen beneath the island. The upper crust beneath this reflector has velocities of 4.0–6.0 km s-1 and is inferred to correspond to plutonic and hypabyssal rocks and sedimentary material of the old arc. The high velocity region beneath the island, extends into the crust to a depth of at least 5 km, and is believed to be caused by an intrusive complex, possibly of intermediate composition. A low velocity zone, as would be expected in the presence of an active magma chamber, was not observed perhaps due to the limited resolution beneath ∼5 km depth. Our results so far provide the first wide-angle seismic constraints on the upper crustal structure of the island to a depth of 10 km, and will help understanding the processes that drive volcanism at Montserrat and other island arc volcanoes.

Lava dome

10.1111/j.1365-246x.2009.04445.x

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Citations (70)

Seismic Velocity/Temperature Correlations and a Possible New Geothermometer: Insights from Exploration of a High-Temperature Geothermal System on Montserrat, West Indies

Energies (2014)

G. Ryan E. Shalev

In 2013, two production wells were drilled into a geothermal reservoir on Montserrat, W.I. (West Indies) Drilling results confirmed the main features of a previously developed conceptual model. The results confirm that below ~220 °C there is a negative correlation between reservoir temperature and seismic velocity anomaly. However, above ~220 °C there is a positive correlation. We hypothesise that anomalous variations in seismic velocity within the reservoir are controlled to first order by the hydrothermal mineral assemblage. This study suggests a new geophysical thermometer which can be used to estimate temperatures in three dimensions with unprecedented resolution and to indicate the subsurface fluid pathways which are the target of geothermal exploitation.

Geothermal exploration

Thermometer

Anomaly (physics)

Seismic velocity

10.3390/en7106689

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Citations (16)

Fresh-saline water interface response to pumping saline groundwater for desalination; evidence from desalination plant in Almeria (Spain)

AGUFM (2019)

Shaked Stein Fernando Sola E. Shalev Yoseph Yechieli Orit Sivan

Saline water

Produced water

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Citations (0)

Cubic B-splines: Strategies of translating a simple structure to B-spline parameterization

Bulletin of the Seismological Society of America (1993)

E. Shalev

Brief Report| October 01, 1993 Cubic B-splines: Strategies of translating a simple structure to B-spline parameterization Eylon Shalev Eylon Shalev Department of Geology Duke UniversityDurham, North Carolina 27706 Search for other works by this author on: GSW Google Scholar Bulletin of the Seismological Society of America (1993) 83 (5): 1617–1627. https://doi.org/10.1785/BSSA0830051617 Article history received: 11 Aug 1992 first online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Eylon Shalev; Cubic B-splines: Strategies of translating a simple structure to B-spline parameterization. Bulletin of the Seismological Society of America 1993;; 83 (5): 1617–1627. doi: https://doi.org/10.1785/BSSA0830051617 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of the Seismological Society of America Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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10.1785/bssa0830051617

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Citations (8)

Cubic B-splines tomography at Loma Prieta

Bulletin of the Seismological Society of America (1998)

E. Shalev Jonathan M. Lees

Abstract A high-resolution tomographic study, using cubic B-splines parameterization and employing a systematic approach to the choosing of appropriate damping and smoothing parameters, provided a three-dimensional P-wave velocity map of the Loma Prieta area. Used in the inversion were 11,977 high-quality raypaths from 844 aftershocks of the 1989 Loma Prieta earthquake. The velocity model exhibits a low-velocity feature between the San Andreas and Zayante-Vergeles faults in the top 10 km of the crust. This low-velocity feature is interpreted as a sedimentary unit exposed to the northwest and separated from the Salinian block by the Zayante-Vergeles fault. Below 10 km, no consistent change is observed between the Salinian and the Franciscan blocks. There appears to be a high correlation of aftershock activity and localized high-velocity anomalies southeast of the Loma Prieta mainshock. Whereas this anomaly may represent brittle rocks associated with a fault-zone asperity that failed after the mainshock, there is evidence to suggest it may be a body of serpentinite. The serpentinite exhibits high velocities and is potentially less competent than surrounding country rock, thus providing a sector along the fault more likely to be associated with many smaller earthquakes or creep behavior.

Asperity (geotechnical engineering)

Upper crust

10.1785/bssa0880010256

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Citations (10)