We address the problem of estimating sound speeds (seismic velocities) inside the earth which is necessary for obtaining seismic images in regular Cartesian coordinates. The main goals are to develop algorithms to convert time migration velocities to true seismic velocities, and to convert time-migrated images to depth images in regular Cartesian coordinates. Our main results are three-fold. Fi...

We address the problem of estimating seismic velocities inside the Earth which is necessary for obtaining seismic images in regular Cartesian coordinates. The main goals are to develop algorithms to convert time-migration velocities to true seismic velocities, and to convert time-migrated images to depth images in regular Cartesian coordinates. Our main results are three-fold. First, we establi...

Animals exposed to anthropogenic disturbance make trade-offs between perceived risk and the cost of leaving disturbed areas. Impact assessments tend to focus on overt behavioural responses leading to displacement, but trade-offs may also impact individual energy budgets through reduced foraging performance. Previous studies found no evidence for broad-scale displacement of harbour porpoises exp...

Sopher, D. 2016. Characterization of the structure, stratigraphy and CO2 storage potential of the Swedish sector of the Baltic and Hanö Bay basins using seismic reflection methods. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1355. 85 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-554-9515-2. An extensive multi-channel seismic dat...

Random noise in seismic data affects the signal-to-noise ratio, obscures details, and complicates identification of useful information. We present a new method for reducing random, spike-like noise in seismic data. The method is based on a 1-D stationary median filter (MF) – the 1-D time-varying median filter (TVMF). We design a threshold value that controls the filter window according to chara...

The objectives of this task are to conduct research on seismic hazards, and provide relevant input on the expected levels of these hazards to other tasks. Other tasks requiring this input include those dealing with inventory, fragility curves, rehabilitation strategies and demonstration projects. The corresponding input is provided in various formats depending on the intended use: as peak groun...

The objectives of this task are both to conduct research on seismic hazards, and to provide relevant input on the expected levels of these hazards to other tasks. Other tasks requiring this input include those dealing with inventory, fragility curves, rehabilitation strategies and demonstration projects. The corresponding input is provided in various formats depending on the intended use: eithe...

The increased availability and fidelity of broadband seismic instruments have played a key role in bridging the gap between exploration and global seismic applications. Long gone are the days when global structure mapping and source characterization/monitoring relied on the manual digitization of WWSSN (World-Wide Standard Seismographic Network) analogue records or hours in front of microfiche ...

Performance-based design is an efficient strategy for assessing and reducing the risk that a construction violates some performance requirement. In this paper, a procedure for performance-based assessment of seismic risk is illustrated with reference to a composite steel-concrete frame structure. Such risk is conventionally evaluated in a simplified formulation, i.e. as the mean annual frequenc...