Andy Nowacki
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View article: Seismic waves generated by explosions in, and above, saturated sediments: the Foulness seismoacoustic coupling trials
Seismic waves generated by explosions in, and above, saturated sediments: the Foulness seismoacoustic coupling trials Open
SUMMARY Seismic signals generated by near-surface explosions, with sources including industrial accidents and terrorism, are often analysed to assist post-detonation forensic characterization efforts such as estimating explosive yield. Exp…
View article: How to assess similarities and differences between mantle circulation models and Earth using disparate independent observations
How to assess similarities and differences between mantle circulation models and Earth using disparate independent observations Open
Mantle circulation in the Earth acts to remove heat from its interior and is thus a critical driver of our planet’s internal and surface evolution. Numerical mantle circulation models (MCMs) driven by plate motion history allow us to model…
View article: The sensitivity of lowermost mantle anisotropy to past mantle convection
The sensitivity of lowermost mantle anisotropy to past mantle convection Open
It is widely believed that seismic anisotropy in the lowermost mantle is caused by the flow-induced alignment of anisotropic crystals such as post-perovskite. What is unclear, however, is whether the anisotropy observations in the lowermos…
View article: The sensitivity of lowermost mantle anisotropy to past mantle convection
The sensitivity of lowermost mantle anisotropy to past mantle convection Open
It is widely believed that seismic anisotropy in the lowermost mantle is caused by the flow-induced alignment of anisotropic crystals such as post-perovskite. What is unclear, however, is whether the anisotropy observations in the lowermos…
View article: Magma storage quantified under Aluto volcano, Ethiopia, using probabilistic tomography
Magma storage quantified under Aluto volcano, Ethiopia, using probabilistic tomography Open
Rift volcanoes worldwide present significant hazards to people from eruptions but also provide resources such as geothermal energy. Aluto volcano in the Ethiopian rift is a hotspot for geothermal power exploitations, despite significant pe…
View article: Icequakes at Sermeq Kujalleq, West Greenland, located by combining borehole distributed acoustic sensing and geophones
Icequakes at Sermeq Kujalleq, West Greenland, located by combining borehole distributed acoustic sensing and geophones Open
The rate of ice loss from marine terminating glaciers is governed by both surface runoff and ice dynamics. Although ice loss due to runoff can be relatively easily studied using in-situ and remote sensing methods, ice dynamics are more dif…
View article: Geophysical surveys to inform heat-flow experiments in a fractured chalk aquifer, Berkshire, UK
Geophysical surveys to inform heat-flow experiments in a fractured chalk aquifer, Berkshire, UK Open
Urban geothermal solutions to heating and cooling have developed slowly in the UK, partly due to limited understanding of subsurface heat flow regimes and how stored heat might be sustainably governed within heterogeneous aquifers. Underst…
View article: Clustering distributed acoustic sensing signals via curvelet transform and unsupervised deep learning
Clustering distributed acoustic sensing signals via curvelet transform and unsupervised deep learning Open
Distributed acoustic sensing (DAS), a technology that exhibits great potential for subsurface monitoring and imaging, has been regarded as a preeminent instrument for vibration measurements. In light of the tremendous amount of seismic dat…
View article: The Global DAS Month of February 2023
The Global DAS Month of February 2023 Open
During February 2023, a total of 32 individual distributed acoustic sensing (DAS) systems acted jointly as a global seismic monitoring network. The aim of this Global DAS Month campaign was to coordinate a diverse network of organizations,…
View article: Excavation Damage Zone fracture modelling for seismic tomography: A comparison of explicit fractures and effective medium approaches
Excavation Damage Zone fracture modelling for seismic tomography: A comparison of explicit fractures and effective medium approaches Open
We model the full wavefield produced by a seismic velocity survey and optimise the representation of the fracture zone to best match field waveforms. The velocity survey was part of a mapping study on fractures in the Excavation Damage Zon…
View article: Upper Mantle Structure Beneath the Contiguous US Resolved With Array Observations of SKS Multipathing and Slowness Vector Perturbations
Upper Mantle Structure Beneath the Contiguous US Resolved With Array Observations of SKS Multipathing and Slowness Vector Perturbations Open
Continent‐scale observations of seismic phenomena have provided multi‐scale constraints of the Earth's interior. Of those analyzed, array‐based observations of slowness vector properties (backazimuth and horizontal slowness) and multipathi…
View article: The Memory of the Mantle: The Influence of a Time Varying Flow Field on Present Day Observations of Seismic Anisotropy
The Memory of the Mantle: The Influence of a Time Varying Flow Field on Present Day Observations of Seismic Anisotropy Open
Seismic anisotropy in the lowermost mantle is thought to be caused by the non-random alignment of anisotropic crystals from texturing from the mantle flowfield. Therefore, seismic anisotropy observations are commonly interpreted in the con…
View article: Global Distributed Fibre Optic Sensing recordings of the February 2023 Turkey earthquake sequence.
Global Distributed Fibre Optic Sensing recordings of the February 2023 Turkey earthquake sequence. Open
As part of a global distributed acoustic sensing (DAS) campaign, multiple DAS interrogators (from academia and industry) recorded simultaneously from 1st till 28th February 2023 in different regions of the globe. The objective is to define…
View article: Efficient neural network-based detection of seismicity in fibre optic data from Store Glacier, West Greenland
Efficient neural network-based detection of seismicity in fibre optic data from Store Glacier, West Greenland Open
Seismic surveys are widely used to characterise the properties of glaciers, their basal material and conditions, and ice dynamics. The emerging technology of Distributed Acoustic Sensing (DAS) uses fibre optic cables as seismic sensors, al…
View article: Wavefield distortion imaging of Earth's deep mantle
Wavefield distortion imaging of Earth's deep mantle Open
The seismic wavefield, as recorded at the surface, carries information about the seismic source and Earth's structure along the seismic path, essential for the understanding of the interior of our planet. For 40 years seismic tomography st…
View article: Upper Mantle Structure beneath the Contiguous US Resolved with Array Observations of SKS Multipathing and Slowness Vector Perturbations
Upper Mantle Structure beneath the Contiguous US Resolved with Array Observations of SKS Multipathing and Slowness Vector Perturbations Open
Continent-scale observations of seismic phenomena have provided multi-scale constraints of the Earth’s interior. Of those analysed, array-based observations of slowness vector properties (backazimuth and horizontal slowness) and multipathi…
View article: Distributed Acoustic Sensing in a Greenlandic Outlet Glacier: Developing Machine Learning Approaches to Benefit Cryoseismic Data Analysis
Distributed Acoustic Sensing in a Greenlandic Outlet Glacier: Developing Machine Learning Approaches to Benefit Cryoseismic Data Analysis Open
The recognition of Distributed Acoustic Sensing (DAS) as a valuable tool for glaciological seismic applications is growing. However, besides the logistical challenges of installing fibre-optic cable, the volume of DAS data that can be coll…
View article: Characterising sediment thickness beneath a Greenlandic outlet glacier using distributed acoustic sensing: preliminary observations and progress towards an efficient machine learning approach
Characterising sediment thickness beneath a Greenlandic outlet glacier using distributed acoustic sensing: preliminary observations and progress towards an efficient machine learning approach Open
Distributed Acoustic Sensing (DAS) is increasingly recognised as a valuable tool for glaciological seismic applications, although analysing the large data volumes generated in acquisitions poses computational challenges. We show the potent…
View article: Lithospheric scattering and intrinsic attenuation characterization from a Bayesian energy flux model 
Lithospheric scattering and intrinsic attenuation characterization from a Bayesian energy flux model  Open
<div> <p><span>P waves are often used to calculate the yield of chemical or nuclear explosions in forensic seismology. These estimations often rely on amplitude measurements affected by seismic scattering and attenuation …
View article: Towards imaging flow at the base of the mantle with seismic, mineral physics and geodynamic constraints
Towards imaging flow at the base of the mantle with seismic, mineral physics and geodynamic constraints Open
Perhaps the least ambiguous signal that the mantle is convecting comes from observations of seismic anisotropy---the variation of wave speed with direction---which must arise due to the ordering of material as deformation occurs. Therefore…
View article: Simplified Seismic Modelling of Fractured Rock: How Effective is the Localised Effective Medium Compared to Explicit Representation of Individual Fractures
Simplified Seismic Modelling of Fractured Rock: How Effective is the Localised Effective Medium Compared to Explicit Representation of Individual Fractures Open
Seismic waves can be an effective probe to retrieve fracture properties particularly when measurements are coupled with forward and inverse modelling. These seismic models then need an appropriate representation of the fracturing. The frac…
View article: Small-scale lithospheric heterogeneity characterization using Bayesian inference and energy flux models
Small-scale lithospheric heterogeneity characterization using Bayesian inference and energy flux models Open
SUMMARY Observations from different disciplines have shown that our planet is highly heterogeneous at multiple scale lengths. Still, many seismological Earth models tend not to include any small-scale heterogeneity or lateral velocity vari…
View article: Accounting for Natural Uncertainty Within Monitoring Systems for Induced Seismicity Based on Earthquake Magnitudes
Accounting for Natural Uncertainty Within Monitoring Systems for Induced Seismicity Based on Earthquake Magnitudes Open
To reduce the probability of future large earthquakes, traffic light systems (TLSs) define appropriate reactions to observed induced seismicity depending on each event's range of local earthquake magnitude ( M L ). The impact of velocity u…
View article: Automatic slowness vector measurements of seismic arrivals with uncertainty estimates using bootstrap sampling, array methods and unsupervised learning
Automatic slowness vector measurements of seismic arrivals with uncertainty estimates using bootstrap sampling, array methods and unsupervised learning Open
SUMMARY Horizontal slowness vector measurements using array techniques have been used to analyse many Earth phenomena from lower mantle heterogeneity to meteorological event location. While providing observations essential for studying muc…
View article: Small-scale lithospheric heterogeneity characterization using Bayesian inference&#160;
Small-scale lithospheric heterogeneity characterization using Bayesian inference  Open
<div> <p>Heterogeneities on the scale of the seismic wavelength in the Earth's crust and mantle cause complex wavefield fluctuations in time and amplitude which are known to affect velocity and source inversions, as well as oth…
View article: Application of machine learning methods to identify englacial seismicity in a Distributed Acoustic Sensing dataset from Store Glacier, West Greenland
Application of machine learning methods to identify englacial seismicity in a Distributed Acoustic Sensing dataset from Store Glacier, West Greenland Open
<p>Seismic surveys are widely used to study the properties of glaciers, basal material and conditions, ice temperature and crystal orientation fabric. The emerging technology of Distributed Acoustic Sensing (DAS) uses fibre optic cab…
View article: Small-scale lithospheric heterogeneity characterization using Bayesian inference
Small-scale lithospheric heterogeneity characterization using Bayesian inference Open
Observations from different disciplines have shown that our planet is highly heterogeneous at multiple scale lengths. Still, many seismological Earth models tend not to include any small-scale heterogeneity or lateral velocity variations, …