Inversion algorithm development for passive electromagnetic detection of line sources: Prototyping a submarine power cable tracking system

The position of installed submarine power cables is often not accurately known for several reasons. The precise knowledge of the cable position is important for the maintenance process and necessitates the need for cable tracking systems. Current systems are in many cases imprecise and have a short sensing distance, limited to a few meters. A...

A multi-pole perfectly matched layer (PML) absorber for finite-difference time-domain (FDTD) seismic modeling in 2D

The multi-pole PML (MPML) is tested on models that simulate seismic waves traveling through the subsurface. Using a recursive integration technique a stretching function consisting of the sum of multiple stretching functions is implemented in the velocity-stress finite difference time domain wave equations. The MPML is implemented in both the...

Exploring Gravitational Waves Recordings with Machine Learning Techniques

The study of Gravitational Waves (GWs) opened a new window of possibilities to improve our understanding of the Universe. GWs provide suitable astronomical messengers for studying events that were not possible before through electromagnetic radiation, or in other cases complementing their observations. Ground-based interferometers like LIGO have...

Ice discharge estimation of the Jakobshavn glacier (Greenland) from 2010 until 2016 using satellite altimetry and satellite gravimetry in combination with RACMO

The Jakobshavn glacier was responsible for approximately 1 mm eustatic sea level rise in the period of 2000 to 2010 [Howat et al. 2011]. As such, the Jakobshavn glacier became one of the largest outlet glaciers in Greenland [Joughin et al. 2004]. Ice flow velocities within the same period reached over 10 km/yr with strong seasonal variation ...

The effect of mechanical stratigraphy on fracture pattern evolution and permeability in faulted carbonates - insights from analogue sandbox models

Dilatant fractures and faults in carbonate rocks play an important role as fluid path for many applications. However, multidimensional characterization of these fractures remains a challenge due to structural complexity in multiscale. The progressive deformation of dilatant fracture in normal fault system from physical models are imaged in 3D...

Full waveform inversion in a MCMC framework

Full-waveform inversion within a deterministic framework commonly uses gradient-based methods to minimize a least-squares error function. Due to the non-linearity of the problem, this function has several local minima. To avoid them, it is necessary to start the optimization procedure from a good initial model. Within a probabilistic framework,...

Marchenko Inversion

Marchenko inversion is a new way to invert seismic or electromagnetic data recorded during geophysical surveys. The inversion method uses Marchenko theory. This is a recent development which enables the retrieval of Green's functions at any place in the subsurface. A non-recursive Marchenko inversion method has already been introduced but in...

Structural Wave Propagation in Unconsolidated Granulates

Unconsolidated granulates exhibit complex, nonlinear behaviour when subjected to dynamic forces. The presence of granular contacts gives this type of material a relatively low stiffness and provides hysteretic energy losses. These features make unconsolidated granulates suitable for railway ballast as it provides dissipation of vibrational...

Pressure and Velocity Fields Retrieval Based on a New Normalization Option and 1D Model-Free Primaries Retrieval from Marine Data: New Marchenko-type Equations with Two-Way Wavefields at the Receiver Level

The Marchenko method is being developed to compute redatuming operators from the reflection response based on a new normalization option at the data level. These operators can be used to retrieve the two-way focusing functions in terms of pressure and velocity, respectively, without effects from the ghost, and free-surface and internal multiples...

From Seismology to Bridge Monitoring: Coda Wave Interferometry

Concrete is the most widely used building material in the world and its stability assessment is of utmost importance for society. Ultrasonic measurements are one tool for investigation of concrete stability. The goal of those measurements is the derivation of damage sensitive parameters. The way ultrasound diffuses through concrete is affected...

Quantification of acquisition uncertainties in seismic wavefield deghosting

Marine seismic acquisition is troubled with several factors of noise that can deteriorate seismic data. Marine seismic data are recorded with towed streamers that acquire the desired upgoing wavefields containing information of the geology beneath. The upgoing wavefield will travel past the streamer/hydrophone to be reflected at the sea surface...