Education

Diploma in Mathematics at Freie Universität Berlin. Diploma Thesis Title: 'Clusteranalyse in Netzwerken – Am Beispiel des Variational Bayesian Expectation Maximization Algorithmus'.

Current project with GeoSim (since 01.10.11)

‘Modelling of Seismic Activity via Network and Time Series Analysis’ at Freie Universität Berlin, Department of Mathematics and Computer Science, Institute of Mathematics.

Supervisors: Christof Schütte (FU Mathematics), Frank Scherbaum (UP Geophysics).

The aim of my work is to achieve a better understanding of the dynamics of seismic activity by using a scalefree modelation of earthquakes via a network approach. For capturing the dynamics of seismic activity in such a network, it has to be coarse grained and analyzed mathematically for introducing, in a second step, fitting methods from time series analysis.

With this approach, a mathematical model which will allow probability based short term predictions of seismic activity is to be developed.

Education

BSc Geology, Master in Project Management and MSc in Marine and Coastal Geology.

Current project with GeoSim (since 01.10.11)

'Probabilistic tsunami hazard assessment for Central America' at department 2.5, GFZ. I use statistical techniques and tsunami modeling to determine main tsunamigenic sources, and to quantify tsunami hazard along Middle America Trench.

Supervisors: Andrey Babeyko (GFZ 2.5), Matthias Holschneider (UP Mathematics)

Conference abstracts 

N. Zamora (2012), Validation of Hyflux2 numerical code: Nias earthquake 2005, in Tsunami Symposium, edited, Ispra, Italy.

N. Zamora (2012), 1. Seismotectonic and geodynamic data for tsunami modeling in Central America. 2. Tsunami hazard along Nicoya Peninsula., in INQUA Active Tectonics Workshop, edited, Morelia, Mexico.

N. Zamora (2012), Tsunami potential along Nicoya peninsula and first results of tsunami risk perception in Tamarindo community., in Field work in Nicoya Peninsula Costa Rica and work at University of Costa Rica, edited, Along Nicoya Península and San José, Costa Rica.

Education

Diploma in Mathematics (2010) at Free University Berlin.

Current project with GeoSim (since 01.01.2012)

'Variational methods for rate- and state-dependent friction models' at Free University Berlin.

Supervisors: Ralf Kornhuber (FU Mathematics), Onno Oncken (GFZ 3.1).

Rate- and state-dependent friction laws can be used to model the tribological behaviour of a number of materials. They have, so far, been met with little interest from the mathematical community. The aim of this project is to embed problems of rate- and state-dependent friction in a variational framework, in order to open them to modern analytical tools as well as fast and robust numerical algorithms.

Conference abstract

Pipping, E. (2012), Variational methods for rate- and state-dependent friction models, in GeoMod, edited, Lausanne, Switzerland.

Education

Diplom in Physics (2011) at RWTH Aachen University. Diploma thesis at Department Nonlinear Dynamics of Laser Processing, NLD, and Fraunhofer Institute for Laser Technology, ILT. Thesis title: 'Analysis of Gas Flows in Laser Cutting Processes with Discontinuous-Galerkin-Methods'.

Current project with GeoSim (since 01.10.2011)

'Numerical modeling and analysis of breaking gravity waves using the One-Dimensional Turbulence model' at the 'Juniorprofessur for flow modeling', BTU Cottbus and the Institute of Mathematics, Department of Mathematics and Computer Sciences, Freie Universtät Berlin.

Supervisors: Heiko Schmidt (BTU Cottbus), Rupert Klein (FU Mathematics)

The energy and momentum deposition through breaking atmospheric gravity waves need to be described in weather and climate models. A 3D turbulence model called ODTLES, based on the stochastic One-Dimensional Turbulence (ODT) model is able to describe the fully developed turbulent spectrum from gravity wave length down to Kolmogorov scale with moderate computing demand. The goal is to use these models stand-alone and coupled with other solvers.

Conference abstracts

C. Glawe, (2012), Stochastic Methods in Fluid Mechanics, in Workshop at "Centre International des Sciences Mecaniques", edited, Udine.

C. Glawe, (2012), Iterative Solvers and Parallelisation, in Workshop at "Hochleistungsrechenzentrum Stuttgart" (High Performance Computing Centre Stuttgart), edited, Stuttgart.

C. Glawe, R. Klein, K. Alan, and H. Schmidt (2012), Towards the simulation of gravity waves using the One-Dimensional Turbulence model, in European Geosciences Union General Assembly, edited.

Education

BA. and MSc. (2011) in Experimental and Theoretical Physics at the University of Cambridge.

Current project with GeoSim (since 01.11.2011)

'Improvement of seismicity models based on Coulomb stress interactions and rate-state dependent friction'

Supervisors: Sebastian Hainzl (GFZ 2.1), Frank Roth (GFZ 2.1)

Physics based aftershock models consider changes in the stress field caused by a mainshock (Coulomb stress), combined with the frictional response of the surrounding faults (Rate-and-State friction). Several sources of uncertainties are present in Coulomb stress calculations, such as errors in the slip models and the choice of receiver faults: one goal of my project is to improve forecast models by correctly accounting for these uncertainties. While Coulomb stress is widely recognized as playing a role in aftershock triggering, the relative effect of co-seismic and post-seismic slip is subject of debate: the model is therefore extended to include an arbitrary (time dependent) stressing history, and the impact of afterslip on the forecasted seismicity is analyzed.

Conference abstracts

C. Cattania  and S. Hainzl (2012), Uncertainties in Coulomb Rate-and-State seismicity models: effects of receiver fault orientation, in IUGG conference, edited, Edimburgh.

C. Cattania, S. Hainzl, and F. Roth (2012), Towards more realistic Coulomb-Rate-and-State seismicity models: effect of receiver fault orientation and afterslip in Fall Meeting, AGU, edited, pp. S54B-03, San Francisco, California.

Education

Geoecology and Geophysics at University of Potsdam. Diploma of Geoecology in 2011.

Current project with GeoSim (since 1.10.2011)

'Sensitivity studies in probabilistic seismic hazard analysis (PSHA).' Institute of Earth and Environmental Sciences, University of Potsdam.

Supervisors: Frank Scherbaum (UP Geophysics), Prof. Dr. Sebastian Reich (UP Mathematics)

Seismic hazard analysis is an important task for reducing the consequences due to devastating earthquakes in vulnerable regions worldwide. The appropriate method for the assessment is probabilistic seismic hazard analysis (PSHA).

PSHA treats ground motion as a random variable and takes into account all possible earthquake occurrences and ground motion scenarios. Therefore, the probabilistic approach enables a complete quantitative consideration of uncertainty. The outcome is a hazard curve quantifying the annual rate of exceedance (or its reciprocal: return period) for different levels of a selected ground motion parameter, such as peak ground acceleration (PGA) or spectral acceleration (SA).

PSHA is based on input assumptions about several parameters, for example characterizing the relative frequencies of occurrence of different earthquakes (e.g. a-value, b-value), the distribution of epicenters or hypocenters (e.g. zonation) and the attenuation and scaling of the amplitude of ground motions (e.g. fc, kappa). It is not always obvious how and to what extent these parameters influence the shape of the hazard curve. In order to determine the impact of individual parameters and also to identify those uncertainties that can be reduced, each PSHA should be accompanied by a sensitivity study. Due to the lack of appropriate tools, this is currently not the case.

The aim of this dissertation is to approach sensitivity analyses in PSHA in a theoretically sound and systematic way, providing quantitative estimates of sensitivity with respect to every relevant parameter.

The approach in favor is known as 'adjoint model' which has been widely used within complex meteorological and oceanographic simulation models to asses the parameter driven uncertainty in model predictions. The goal of the thesis is to implement the 'adjoint model' approach for PSHA and explore its potential for large scale seismic hazard problems.

Education

M.Tech (Computational Seismology) Indian Institute of Technology Kharagpur, India. Title of the master thesis: “Deterministic Seismic Hazard Assessment in India & Adjoining Regions and A Probabilistic Pilot Study in Gujarat, Western India.”

Current project with GeoSim (since 1.10.2011)

‘Regionally adaptable Ground Motion Prediction Equations’ at the Institute of Earth and Environmental Sciences, University of Potsdam.

Supervisors: Frank Scherbaum (UP Geophysics), Sebastian Reich (UP Mathematics)

The precise prediction of ground motion for future earthquake scenarios is a key issue in seismic hazard analysis. In this context empirical Ground Motion Prediction Equations (GMPEs) are used. The GMPEs are derived by regression analysis from observed ground motion data such as peak ground acceleration (PGA) or response spectral values against a chosen set of predictor values. There are many regions in the world where the number of the earthquake recordings are not sufficient in quantity and quality to generate endemic GMPEs particularly in intra-plate regions e.g. Gujarat western India. As a result GMPEs have to be imported from other regions. That requires modification to accommodate changes in source and path characteristics such as stress drop, quality factor, and kappa values between the host region and the target region. The idea for my PhD thesis is to generate GMPEs with a different approach using the linear system theory. I will use the Random Vibration Theory (RVT) to calculate the response spectrum from Fourier spectrum and duration model of ground motion. The changes in stress drop, kappa, and quality factor values will be accommodated by adding an appropriate frequency response function in Fourier spectrum model. Consequently the Fourier spectrum model will be combined with the duration model to give the modified response spectrum model. Since the Fourier spectrum model is considered as representing, the actual physics of the process, pertaining to some assumptions. Therefore the proposed research work is believed to add new insights in seismic hazard analysis by developing a response spectrum model through Fourier spectrum model.

Conference abstracts

S. Singh Bora, (2012), OralGround Motion Prediction: A Fourier Spectrum Approach, GEOSIM Fall Workshop, Golm

S. Singh Bora, F. Scherbaum, N. Kuehn and P. Stafford (2013), Fourier Spectral- and Duration Models for the Generation of Response Spectra Adjustable to Different Source-, Path- and Site conditions, SSA Annual Meeting, Salt Lake City, USA. Winner of best student poster award (top 10%)

Education

Diplom in mathematics at Freie Universität Berlin. Thesis title: "Numerical methods for the linear advection equation: Plateaus vs. Extrema"

Current project with GeoSim: (since 01.10.2011)

"Advanced finite volume schemes numerics for advection dominated problems" at the Institute of Mathematics, Department of Mathematics and Computer Sciences, Freie Universtät Berlin

Supervisors: Rupert Klein (FU Mathematics), Uwe Ulbrich (FU Meteorology)

The goal of my work is to compare existing numerical methods, find improvements or develope new ones, that yield satisfying results for solving geophysical problems - in particular advection dominated problems.

Education

MSc in Geology at the University of the Philippines Diliman, Quezon City

Current project with GeoSim (since 01.10.11)

‘Hydrologic simulations using rainfall radar data for flood forecasting in Marikina River Basin, Philippines’ at the Hydrology and Climatology group, Institute of Earth and Environmental Science, Potsdam University.

Supervisors: Axel Bronstert (UP Hydrology), Ralf Kornhuber (FU Berlin)

Improving flood preparedness through early warning systems is a necessity for countries like the Philippines where flooding is frequent. Particularly for river basins that host huge settlements such as the Marikina River Basin (MRB), an early flood forecast can potentially reduce the hazards associated with floods. The MRB has an area of 535 km2, and for huge typhoons such as Ketsana in 2009 the reaction time is four to five hours. For an early warning system, a hydrological model will be implemented which is capable of producing flood forecasts that can give a lead within the reaction time of the basin. The model uses a flexible modeling framework, the framework Eco-Hydrological Simulation Environment (ECHSE), in order to consider specific hydrological processes in the catchment. Beyond, I will evaluate the potential of rainfall radar data as precipitation forcing—a novel application in the Philippines as a new network of C- and S-band radars is just being implemented. For this purpose, the new Open-Source radar processing library wradlib will be employed.

Conference abstracts

C. Abon, (2012), Hydrologic simulations using rainfall radar data for flood forecasting in Marikina River Basin, Philippines, in EGU 2012, edited, Vienna, Austria.

Education

Diploma in Geography at the University of Bonn in 2009. Thesis: "Regionalization of runoff data in Norway."

Current project with GeoSim (since 01.04.2012)

“Uncertainties in climate change impacts on hydrological extremes”, Hydrology and Climatology Group, Institute for Earth and Environmental Science, University of Potsdam

Supervisors: Axel Bronstert (UP Hydrology), Sebastian Reich (UP Mathematics), Deborah Lawrence (external, Norwegian Water Resources and Energy Directorate)

Projections on the hydrologic impacts of climate change at the catchment scale are highly uncertain – especially for extremes. Uncertainties emerge from various sources and accumulate throughout the model chain, beginning with large scale Global Circulation Models estimating changes in climate variables based on emission scenarios, over dynamical or statistical downscaling techniques intending to adjust this information to smaller scales, and finally to the hydrological models which introduce uncertainties due to model parameterization and model structure. This study will simulate changes in flood frequency in selected Norwegian catchments due to climate change and focus on the uncertainties that are affiliated with these projections. A special emphasis will be on the uncertainties that arise from statistical downscaling techniques and hydrologic model parameterizations.

Conference abstract

K. Vormoor and T. Skaugen (2012), Temporal disaggregation of daily meteorological grid data, in EGU General Assembly, edited, Vienna.