Delineating a shallow fault zone and dipping bedrock strata using multichannal analysis of surface waves with a land streamer

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. A39-A42 ◽  
Author(s):  
Julian Ivanov ◽  
Richard D. Miller ◽  
Pierre Lacombe ◽  
Carole D. Johnson ◽  
John W. Lane
Keyword(s):  
Surface Waves ◽  
Fault Zone ◽  
Large Scale ◽  
Seismic Source ◽  
Geologic Mapping ◽  
Lower Shear ◽  
Weight Drop ◽  
Secondary Fractures ◽  
Masw Method ◽  
A Site

The multichannel analysis of surface waves (MASW) seismic method was used to delineate a fault zone and gently dipping sedimentary bedrock at a site overlain by several meters of regolith. Seismic data were collected rapidly and inexpensively using a towed 30-channel land streamer and a rubberband-accelerated weight-drop seismic source. Data processed using the MASW method imaged the subsurface to a depth of about [Formula: see text] and allowed detection of the overburden, gross bedding features, and fault zone. The fault zone was characterized by a lower shear-wave velocity [Formula: see text] than the competent bedrock, consistent with a large-scale fault, secondary fractures, and in-situ weathering. The MASW 2D [Formula: see text] section was further interpreted to identify dipping beds consistent with local geologic mapping. Mapping of shallow-fault zones and dipping sedimentary rock substantially extends the applications of the MASW method.

Wavelet analysis of the temporal-spatial distribution in the Eurasia seismic belt

2017 ◽  
Vol 15 (03) ◽  
pp. 1750018 ◽  
Author(s):  
Wenfeng Zheng ◽  
Xiaolu Li ◽  
Lirong Yin ◽  
Zhengtong Yin ◽  
Bo Yang ◽  
...  
Keyword(s):  
Fault Zone ◽  
Compact Support ◽  
Large Scale ◽  
Temporal Distribution ◽  
Seismic Energy ◽  
Research Area ◽  
Earthquake Activity ◽  
Seismic Zone ◽  
Seismic Belt ◽  
Earthquake Fault

Due to the growing frequency of earthquakes, safeties of human lives and properties are facing serious threats. However, the research in the field of spatial-temporal distribution of earthquake is quite a few. In this paper, we use wavelet model to analyze the spatial-temporal distribution of earthquakes. Because the spatial-temporal distribution of earthquake activity is closely related to the distribution of the earthquake fault zone, we analyze large-scale earthquake clusters by selecting the Eurasia seismic belt and the surrounding region as the research area. From the perspective of the time domain, the results show that the seismic energy of the earthquake fault zone presences compact support or similar compact support distribution, suggesting that the seismic zone exists a relatively quiet period and active stage. This indicate that the seismic zone is periodical. The period of strong earthquakes above normal and less than normal is different by time changes. The cycles of earthquakes are different due to different regions and different geological and geographical environment.

scholarly journals Evaluation of Various Perimeter Barrier Products

2021 ◽  
Author(s):  
Rabin Bhattarai ◽  
◽  
Yufan Zhang ◽  
Jacob Wood ◽  
◽  
...  
Keyword(s):  
Large Scale ◽  
Sediment Concentration ◽  
Department Of Transportation ◽  
Vegetative Cover ◽  
Buffer Strip ◽  
Erosion Rates ◽  
Sediment Removal ◽  
Loam Soil ◽  
A Site ◽  
Large Scale Tests

Construction activities entail substantial disturbance of topsoil and vegetative cover. As a result, stormwater runoff and erosion rates are increased significantly. If the soil erosion and subsequently generated sediment are not contained within the site, they would have a negative off-site impact as well as a detrimental influence on the receiving water body. In this study, replicable large-scale tests were used to analyze the ability of products to prevent sediment from exiting the perimeter of a site via sheet flow. The goal of these tests was to compare products to examine how well they retain sediment and how much ponding occurs upstream, as well as other criteria of interest to the Illinois Department of Transportation. The products analyzed were silt fence, woven monofilament geotextile, Filtrexx Siltsoxx, ERTEC ProWattle, triangular silt dike, sediment log, coconut coir log, Siltworm, GeoRidge, straw wattles, and Terra-Tube. Joint tests and vegetated buffer strip tests were also conducted. The duration of each test was 30 minutes, and 116 pounds of clay-loam soil were mixed with water in a 300 gallon tank. The solution was continuously mixed throughout the test. The sediment-water slurry was uniformly discharged over an 8 ft by 20 ft impervious 3:1 slope. The bottom of the slope had a permeable zone (8 ft by 8 ft) constructed from the same soil used in the mixing. The product was installed near the center of this zone. Water samples were collected at 5 minute intervals upstream and downstream of the product. These samples were analyzed for total sediment concentration to determine the effectiveness of each product. The performance of each product was evaluated in terms of sediment removal, ponding, ease of installation, and sustainability.

3D elastic full-waveform inversion of surface waves in the presence of irregular topography using an envelope-based misfit function

Geophysics ◽  
2018 ◽  
Vol 83 (1) ◽  
pp. R1-R11 ◽  
Author(s):  
Dmitry Borisov ◽  
Ryan Modrak ◽  
Fuchun Gao ◽  
Jeroen Tromp
Keyword(s):  
Surface Wave ◽  
Objective Function ◽  
Surface Waves ◽  
Large Scale ◽  
Body Wave ◽  
Waveform Inversion ◽  
Full Waveform Inversion ◽  
S Wave ◽  
Near Surface ◽  
Full Waveform

Full-waveform inversion (FWI) is a powerful method for estimating the earth’s material properties. We demonstrate that surface-wave-driven FWI is well-suited to recovering near-surface structures and effective at providing S-wave speed starting models for use in conventional body-wave FWI. Using a synthetic example based on the SEG Advanced Modeling phase II foothills model, we started with an envelope-based objective function to invert for shallow large-scale heterogeneities. Then we used a waveform-difference objective function to obtain a higher-resolution model. To accurately model surface waves in the presence of complex tomography, we used a spectral-element wave-propagation solver. Envelope misfit functions are found to be effective at minimizing cycle-skipping issues in surface-wave inversions, and surface waves themselves are found to be useful for constraining complex near-surface features.

A risk-reduction framework for urban cultural heritage: a comparative study on Italian historic centres

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Francesca Giuliani ◽  
Rosa Grazia De Paoli ◽  
Enrica Di Miceli
Keyword(s):  
Cultural Heritage ◽  
Social Life ◽  
Large Scale ◽  
Qualitative Assessment ◽  
Content Type ◽  
Heritage Sites ◽  
Step Procedure ◽  
Response And Recovery ◽  
A Site ◽  
Key Resources

PurposeThe purpose of this paper is to present and validate a large-scale methodology for risk assessment and management in cultural heritage sites, taking into account their specific tangible or intangible values. Emphasis is given to historic centres that are key resources in building resilience to disasters but are also highly vulnerable due to several factors, such as the characteristics of the built environment, the community and social life, the lack of risk awareness and maintenance and finally the poor regulatory framework for their management and valorisation.Design/methodology/approachThe multi-step procedure starts from the assessment of the attributes of cultural heritage in order to identify priorities and address the analysis. Then, it evaluates the primary and secondary hazards in the area, the vulnerabilities and threats of the site and the impacts of the chain of events. Finally, it allows for calibrating a site-specific set of mitigation, preparedness, response and recovery measures.FindingsThe application to two case studies in the Italian peninsula, the historic centres of San Gimignano and Reggio Calabria, allows for identifying research gaps and practical opportunities towards the adoption of common guidelines for the selection of safety measures.Originality/valueBy providing a qualitative assessment of risks, the research points out the potentialities of the methodology in the disaster risk management of cultural heritage due to its capacity to be comprehensive and inclusive towards disciplines and professionals.

The Natural and Constructed Landscape of Salinas de los Nueve Cerros, Guatemala

2020 ◽  
pp. 39-60
Author(s):  
Brent K. S. Woodfill ◽  
Marc Wolf
Keyword(s):  
Large Scale ◽  
Scale Production ◽  
Oxbow Lakes ◽  
Ancient Maya ◽  
Salted Fish ◽  
Local Elite ◽  
Large Scale Production ◽  
Salt Flats ◽  
Salt Industry ◽  
A Site

Chapter 3, presented by Brent K. S. Woodfill and Marc Wolf, introduces Salinas de los Nueve Cerros, a site located at the highland-lowland nexus in western Guatemala, best known as being the largest of the ancient Maya saltworks in the southern lowlands. The site’s natural and constructed monumental landscape defined not only the city’s layout but also its economy and political structure. The most obvious of the saltworks were the brine stream and salt flats, but the salt industry changed the landscape in other ways—it was fueled by fires that needed a constant supply of firewood and allowed for the large-scale production of other commodities including dried, salted fish, which were harvested in large quantities from the Chixoy River and associated streams and oxbow lakes. All of these resources appear to have been tightly controlled by the local elite, who marked their presence with large administrative and public ritual structures.

scholarly journals An Audit of Perioperative Blood Transfusions in a Regional Hospital to Rationalise a Maximum Surgical Blood Ordering Schedule

2018 ◽  
Vol 46 (5) ◽  
pp. 498-503
Author(s):  
R. M. Blank ◽  
S. P. Blank ◽  
H. E. Roberts
Keyword(s):  
Large Scale ◽  
Major Amputation ◽  
Joint Arthroplasty ◽  
Blood Transfusions ◽  
Local Data ◽  
Preoperative Testing ◽  
Site Specific ◽  
Retrospective Audit ◽  
A Site ◽  
Cross Matching

Appropriate preoperative blood typing and cross-matching is an important quality improvement target to minimise costs and rationalise the use of blood bank resources. This can be facilitated using a maximum surgical blood ordering schedule (MSBOS) for specific operations. It is recommended that individual hospitals develop a site-specific MSBOS based on institutional data, but this is challenging in non-tertiary centres without electronic databases. Our aim was to audit our perioperative blood transfusions to develop a site-specific MSBOS. A retrospective audit of blood transfusions in surgical patients in our regional referral hospital was conducted using five years’ coded administrative data. Procedures with higher transfusion rates warranting preoperative testing (type and screen with or without subsequent cross-matching) were identified. There were about 15,000 eligible surgical procedures performed in our institution over the audit period. The need for preoperative testing was identified for only a few procedures, namely laparotomy, bowel resection, major amputation, joint arthroplasty, hip/femur fracture and humerus surgery, and procedures for obstetric complications. We observed a reduction in transfusion rates over time for total joint arthroplasty. The use of coding data represents an efficient method by which centres without electronic anaesthesia information management systems can conduct large-scale audits to develop a site-specific MSBOS. This would represent a significant improvement for hospitals that currently base preoperative testing recommendations on expert opinion alone. As many procedures in regional centres have very low transfusion rates, hospitals with a similar case mix to ours could consider selectively auditing higher-risk operations where local data is most likely to alter testing recommendations.

scholarly journals Biases in Thorpe-Scale Estimates of Turbulence Dissipation. Part I: Assessments from Large-Scale Overturns in Oceanographic Data

2015 ◽  
Vol 45 (10) ◽  
pp. 2497-2521 ◽  
Author(s):  
Benjamin D. Mater ◽  
Subhas K. Venayagamoorthy ◽  
Louis St. Laurent ◽  
James N. Moum
Keyword(s):  
Large Scale ◽  
Companion Paper ◽  
Open Ocean ◽  
Luzon Strait ◽  
Length Scale ◽  
Ensemble Averaging ◽  
Tidal Period ◽  
Thorpe Scale ◽  
Order Of Magnitude ◽  
A Site

AbstractOceanic density overturns are commonly used to parameterize the dissipation rate of turbulent kinetic energy. This method assumes a linear scaling between the Thorpe length scale LT and the Ozmidov length scale LO. Historic evidence supporting LT ~ LO has been shown for relatively weak shear-driven turbulence of the thermocline; however, little support for the method exists in regions of turbulence driven by the convective collapse of topographically influenced overturns that are large by open-ocean standards. This study presents a direct comparison of LT and LO, using vertical profiles of temperature and microstructure shear collected in the Luzon Strait—a site characterized by topographically influenced overturns up to O(100) m in scale. The comparison is also done for open-ocean sites in the Brazil basin and North Atlantic where overturns are generally smaller and due to different processes. A key result is that LT/LO increases with overturn size in a fashion similar to that observed in numerical studies of Kelvin–Helmholtz (K–H) instabilities for all sites but is most clear in data from the Luzon Strait. Resultant bias in parameterized dissipation is mitigated by ensemble averaging; however, a positive bias appears when instantaneous observations are depth and time integrated. For a series of profiles taken during a spring tidal period in the Luzon Strait, the integrated value is nearly an order of magnitude larger than that based on the microstructure observations. Physical arguments supporting LT ~ LO are revisited, and conceptual regimes explaining the relationship between LT/LO and a nondimensional overturn size are proposed. In a companion paper, Scotti obtains similar conclusions from energetics arguments and simulations.

RECUPERATION, TRANSFORMATION AND THE TRANSCENDENCE OF MAJOR OVER MINOR IN THE FINALE OF HAYDN’S STRING QUARTET OP. 76 NO. 1

2008 ◽  
Vol 5 (1) ◽  
pp. 27-50 ◽  
Author(s):  
FLOYD GRAVE
Keyword(s):  
Eighteenth Century ◽  
String Quartet ◽  
Large Scale ◽  
A Site ◽  
Tonal System

ABSTRACTWhen the French critic Bernard Germain Lacépède identified minor harmony with inner pain, restlessness and torment (La poétique de la musique, 1785), he was recognizing what had evolved as a lopsided dichotomy within the tonal system: rather than viewing major and minor as equivalent, mutually defining opposites, later eighteenth-century musicians often viewed the latter as a site of disturbing associations and thus potentially problematic as the foundation for large-scale instrumental compositions. Against this backdrop, it is notable that Haydn ended most of his later minor-key works in major, and in the finales of his quartets Op. 76 Nos 1–3 he exploits modal reversal as a special theme by having each begin in minor before undergoing an artfully contrived switch to major. Because the tonality of two of these quartets was major to begin with, Nos 1 in G and 3 in C, this entailed a double reversal: from major to minor as the finale began, from minor to major at a crucial moment prior to the end. The finale of Op. 76 No.1 surpasses the others of this group in tonal range, intricate play of symmetries and palpable connections to its preceding movements. Crowning it is a coda that turns the movement’s stark opening unison into a cheerful rustic tune. Thus opening theme and coda, although diametrically opposed in topic and imagery, are heard to share the same underlying identity. The result may be read as a vividly evoked musical subject whose vicissitudes trace a path from darkness to light, from turmoil and confusion to a state of pastoral joy and contentment.

Sign in / Sign up

Export Citation Format

Share Document