Connections between intermediate & shallow-focus earthquakes and tectonic faults based on data of CDP seismic survey method

Seismic vulnerability of an urban environment is characterized by the ability of buildings and structures to support seismic events (physical vulnerability) and by the ability of people to behave in a consistent and rational face a major event (social vulnerability). Constantine is a city with moderate seismicity but the level of risk is high because of urban concentration and topography of the site. The seismic risk reduction therefore requires assessing the physical vulnerability of its buildings. It is proposed in this paper an analysis of a group of buildings for residential use located west of the city, consisting mainly of relatively high buildings. Following a survey of a portion of the housing stock of this city, a seismic survey method was applied based on "observations" post-seismic. Vulnerability indicators are statistically related to damage through a vulnerability index "IV" to establish curves of damage (or vulnerability). These are used to estimate the level of damage that is likely resulting in damage cards. The goal is to develop an initial database of some of the housing stock in the Constantine city (knowledge of earthquake hazards, construction defects ...) to be used in the estimation of seismic risk and verification of seismic safety of existing buildings. Keywords: Earthquake hazard; Seismic vulnerability; Constantine city; damage.

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Resolving a velocity inversion at the geotechnical scale using the microtremor (passive seismic) survey method

Exploration Geophysics ◽

10.1071/eg04014 ◽

2004 ◽

Vol 35 (1) ◽

pp. 14-18 ◽

Cited By ~ 37

Author(s):

James C. Roberts ◽

Michael W. Asten

Keyword(s):

Seismic Survey ◽

Survey Method ◽

Velocity Inversion ◽

Passive Seismic

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Mine seismic prediction of tectonic faults by reflected waves using the method of location

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2020-6-0-131-139 ◽

2020 ◽

pp. 131-139

Author(s):

A. V. Antsiferov ◽

A. A. Glukhov ◽

V. A. Antsiferov

Keyword(s):

Data Processing ◽

Phase Synchronization ◽

Seismic Survey ◽

Reflected Waves ◽

Tectonic Faults ◽

Geological Anomaly ◽

First Arrival ◽

Reflecting Boundaries ◽

The Common ◽

Seismic Prediction

The article presents the case-study of geological anomaly delineation by reflected waves in seismic logs of the common excitation point and the common receipt point using a dedicated software. The proposed data processing flow consists in consistent fulfillment of a sequence of stages. Sorting of seismic logs is followed by band and band-elimination filtering, selection of optimal filter passband and identification of interfering axes of phase synchronization of different-nature waves. The axes of phase synchronization of information-bearing waves are identified by the points of the first arrivals. By these points, ellipses are automatically drawn so that their focuses are at the excitation and receipt points while the value of doubled semi-axes is equal to the product of velocity and first arrival time of a wave. The criterion of reflecting boundaries is the distinctive approach or intersection of the ellipses in a local zone of a supposed reflecting boundary. The data processing algorithm allows revealing tectonic faults within a radius to 200 m around a roadhead. Reflecting boundaries at greater distances from roadheads are located on an estimation basis. The developed algorithm and software can be used by geophysical services and specialized geological exploration agencies for processing and analysis of seismic survey data when predicting structure of coal-and-rock masses.

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Integrated Seismic Hazard Analysis Of Southwest Penang Island Through Horizontal-To-Vertical Spectral Ratio And Probabilistic Seismic Hazard Assessment

Bulletin of the Geological Society of Malaysia ◽

10.7186/bgsm71202107 ◽

2021 ◽

Vol 71 ◽

pp. 79-87

Author(s):

Siti Noor Shafiqah Badrolhisham ◽

◽

Abdul Halim Abdul Latiff

Keyword(s):

Seismic Hazard ◽

Hazard Assessment ◽

Ground Motions ◽

Seismic Hazard Assessment ◽

Spectral Ratio ◽

Seismic Survey ◽

Survey Method ◽

Probabilistic Seismic Hazard Assessment ◽

Probabilistic Seismic Hazard ◽

Loose Deposits

Peninsular Malaysia is susceptible to large magnitude earthquakes induced by the regional sources as it is surrounded by countries that are known for their active seismicity. Tremors were felt in Penang Island of Pulau Pinang due to earthquake events in Sumatra, Indonesia in 2005 and 2009. Presence of cracks on buildings in the island was reported caused by the earthquake on 2nd November 2002. The tsunami that hit the island on 26 December 2004 was the aftermath of the Great Sumatra-Andaman earthquake with magnitude 9.1. The investigation of earthquake risks ensures that the effect of earthquake disasters in the inclined region can be reduced effectively. This paper aims to provide a comprehensive seismic hazard assessment in Penang Island by analysing the predominant natural frequency distribution in Balik Pulau through a passive seismic survey method known as horizontal-to-vertical spectral ratio (HVSR) and evaluating the ground motion throughout the island using probabilistic seismic hazard assessment (PSHA) approach. The natural frequencies of Balik Pulau mostly falls in the range of 3 to 4 Hz which is associated with loose deposits and stiff soil layer. The amplification factor extracted from the HVSR curves ranges approximately 4 to 5. The minimum ground motions estimated for a fixed intensity in 50 years for Penang Island is 0.006 g1 and can reach up to 0.025 g. While the minimum ground motions for a fixed return period of 98 years in 50 years is 0.016 g with maximum of 0.035 g.

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A Quantitative Assessment of the Annual Contribution of Platform Down Wearing to Beach Sediment Budget: Happisburgh, England, UK

10.20944/preprints201809.0348.v1 ◽

2018 ◽

Author(s):

Andres Payo ◽

Mike Walkden ◽

Michael A. Ellis ◽

Andrew Barkwith ◽

David Favis-Mortlock ◽

...

Keyword(s):

Sediment Budget ◽

Seismic Survey ◽

Survey Method ◽

Coastal Protection ◽

Volume Data ◽

Beach Sediment ◽

Passive Seismic ◽

Order Of Magnitude ◽

Modelling Environment ◽

Sand And Gravel

Field and numerical investigations at Happisburgh, East coast of England, UK, sought to characterize beach thickness and determine geologic framework controls on coastal change. After a major failure of coastal protection infrastructure, removal of about 1 km of coastal defense along the otherwise protected cliffed coastline of Happisburgh triggered a period of rapid erosion over 20 years of ca. 140 m. Previous sensitivity studies suggested that that beach thickness plays a major role in coastal recession. These studies were limited, however, by a lack of beach volume data. In this study, we have integrated the insights gained from our understanding of the Quaternary geology of the area, a novel non-intrusive passive seismic survey method, and a 3D novel representation of the subsurface source and transportable material into a coastal modelling environment to explore the role of beach thickness on the back wearing and down wearing of the cliffs and consolidated platform, respectively. Results show that beach thickness is non-homogeneous along the study site: we estimate that the contribution to nearshore sediment budget via platform down wearing is of a similar order of magnitude as sediment lost from the beach and therefore non-negligible. We have provided a range of evidence to support the idea that the Happisburgh beach is a relatively thin layer perched on a sediment rich platform of sand and gravel. This conceptualization differs from previous publications, which assumes that the platform was mostly till and fine material. This has direct implication on the regional sediment management of along this coastline. The present study contributes to our understanding of a poorly known aspect of coastal sediment budgeting and outlines a quantitative approach that allows for simple integration of geological understanding for coastline evolution assessments worldwide.

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A Quantitative Assessment of the Annual Contribution of Platform Downwearing to Beach Sediment Budget: Happisburgh, England, UK

Journal of Marine Science and Engineering ◽

10.3390/jmse6040113 ◽

2018 ◽

Vol 6 (4) ◽

pp. 113 ◽

Cited By ~ 4

Author(s):

Andres Payo ◽

Mike Walkden ◽

Michael Ellis ◽

Andrew Barkwith ◽

David Favis-Mortlock ◽

...

Keyword(s):

Sediment Budget ◽

Seismic Survey ◽

Survey Method ◽

Coastal Protection ◽

Volume Data ◽

Beach Sediment ◽

Passive Seismic ◽

Order Of Magnitude ◽

Modelling Environment ◽

Sand And Gravel

Field and numerical investigations at Happisburgh, East coast of England, UK, sought to characterize beach thickness and determine geologic framework controls on coastal change. After a major failure of coastal protection infrastructure, removal of about 1 km of coastal defence along the otherwise protected cliffed coastline of Happisburgh triggered a period of rapid erosion over 20 years of ca. 140 m. Previous sensitivity studies suggest that beach thickness plays a major role in coastal recession. These studies were limited, however, by a lack of beach volume data. In this study, we have integrated the insights gained from our understanding of the Quaternary geology of the area, a novel non-intrusive passive seismic survey method, and a 3D novel representation of the subsurface source and transportable material into a coastal modelling environment to explore the role of beach thickness on the back wearing and downwearing of the cliffs and consolidated platform, respectively. Results show that beach thickness is non-homogeneous along the study site: we estimate that the contribution to near-shore sediment budget via platform downwearing is of a similar order of magnitude as sediment lost from the beach and therefore non-negligible. We have provided a range of evidence to support the idea that the Happisburgh beach is a relatively thin layer perched on a sediment rich platform of sand and gravel. This conceptualization differs from previous publications, which assume that the platform was mostly till and fine material. This has direct implication on regional sediment management along this coastline. The present study contributes to our understanding of a poorly known aspect of coastal sediment budgeting and outlines a quantitative approach that allows for simple integration of geological understanding for coastline evolution assessments worldwide.

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FAULT PLANE RESOLUTION USING THE LOW-FOLD 3D SEISMIC TECHNIQUE OVER WOODADA GAS FIELD, PERTH BASIN, WESTERN AUSTRALIA

The APPEA Journal ◽

10.1071/aj86023 ◽

1987 ◽

Vol 27 (1) ◽

pp. 289

Author(s):

B.J. Evans ◽

G.A. Paterson ◽

S.E. Frey

Keyword(s):

Western Australia ◽

Seismic Data ◽

Joint Venture ◽

Seismic Survey ◽

Survey Method ◽

3D Seismic ◽

Coherent Noise ◽

Gas Field ◽

Single Fold ◽

Processing Techniques

During August 1984, a conventional 2D seismic line and a single fold 3D seismic survey were recorded over the Woodada Gas Field, North Perth Basin, Western Australia. This survey was a joint venture between the Allied Geophysical Laboratories at the University of Houston and the Exploration Seismology Centre's Field Research Laboratory at the Western Australian Institute of Technology. Previous seismic data were so poor that there was confusion about fault orientation and structure in the survey area. In addition, the fault strike direction and extent were unknown at this location. Consequently, 3D seismic acquisition and processing techniques appeared highly applicable to this geological problem.In general, progressive development of seismic data acquisition methods has been towards higher channel, higher multifold 2D and 3D surveys. However, at the Allied Geophysical Laboratories, processing techniques for single-fold 3D data have been developed using model tank data. This processing technique — LO-FOLD 3D — was used to field trial the method, and to test its ability to define faulting between the gas producing well Indoon 1 and dry step-out well Woodada 9. Previous usage of the single-fold 3D survey method was to delineate reefal structures in the Michigan Basin. Beyond this, no published articles discuss the method.With single-fold data, velocity analysis and coherent noise are a problem. Consequently, 2D bin lines through the 3D volume of data were processed in order to improve the signal to noise ratios. The objective was to delineate the fault orientation in the Carynginia Formation, located between 1.3 and 1.5 seconds. Fault delineation was determined from 2D bin lines and time slices, and is interpreted to run diagonally between the two wells.

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