fakultät für geowissenschaften

The investigation of the impact of Global Change on the basic resources on which life, and man, depends, is the main objective of the environmental science community at the beginning of the 21st century. Advances in information technology, new methods of spatially distributed data retrieval and increased understanding of the physical, chemical and biological processes in the Earth system facilitate integrative models of the dynamic processes under change. Together with the integration of deep actors models from social and economical sciences into a common model framework, scenario runs based on inputs from Regional Climate Models (RCMs) and constrained by prognoses of the future developments in demography, economy and human behaviour are now possible. The objective of the integrative project GLOWA-Danube is the development of such a modelling system and its application on the mesoscale catchment of the Upper Danube river with an area of about 77,000 km2. The decision support system DANUBIA is designed for plausible predictions of the impact of changes in climate, human behaviour and land use on the future of the water and related matter cycles. DANUBIA is able to assist knowledge-based management decisions, by predicting the effects of adaptation and mitigation strategies on the natural resources of the Upper Danube basin. The closure of the water, energy, nitrogen and carbon cycles in the soil-vegetation-atmosphere system relies on the adequate representation of all processes involved and their interaction. To close the energy cycle in the soil-vegetation-atmosphere system and provide valuable input data for biochemical models of soil nitrogen and carbon transformation, this thesis presents the Soil Heat Transfer Module (SHTM) together with an energy balance algorithm of the soil surface for regional scale simulations. SHTM combines simplified physical algorithms for the computation of the actual temperature in the upper soil layers and a dynamic lower boundary condition to represent Climate Change conditions. Changes in soil moisture and soil freezing are explicitly taken into account. The surface ground heat flux as the driving force of the model is provided by an explicit solution of the soil surface energy balance and a snow-soil coupling algorithm, respectively. This thesis shows, that the soil temperature and energy balance modules developed as extensions of PROMET (PROcesses of Matter and Energy Transfer) are ready to bridge the gap between regional scale (up to 100,000 km2) application and the requirement of physical process models in predictive, coupled modelling systems like DANUBIA.

The aim of this work is to develop an experimental method to measure in-plane surface properties on the nanometer scale by torsional resonance mode atomic force microscopy and to understand the underlying system dynamics. The invention of the atomic force microscope (AFM) and the advances in development of new AFM based techniques have significantly enhanced the capability to probe surface properties with nanometer resolution. However, most of these techniques are based on a flexural oscillation of the force sensing cantilever which are sensitive to forces perpendicular to the surface. Therefore, there is a need for highly sensitive measurement methods for the characterization of in-plane properties. To this end, scanning shear force measurements with an AFM provide access to surface properties such as friction, shear stiffness, and other tribological surface properties with nanometer resolution. Dynamic atomic force microscopy utilizes the frequency response of the cantilever-probe assembly to reveal nanomechanical properties of the surface. The frequency response function of a cantilever in torsional motion was investigated by using a numerical model based on the finite element method (FEM). We demonstrated that the vibration of the cantilever in a torsional oscillation mode is highly sensitive to lateral elastic (conservative) and visco-elastic (non-conservative) in-plane material properties, thus, mapping of these properties is possible in the so-called torsional resonance mode AFM (TR-mode). The theoretical results were then validated by implementing a frequency modulation (FM) detection technique to torsion mode AFM. This method allows for measuring both conservative and non-conservative interactions. By monitoring changes of the resonant frequency and the oscillation amplitude, we were able to map elastic properties and dissipation caused by the tip-sample interaction. During approach and retract cycles, we observed a slight negative detuning of the torsional resonance frequency, depending on the tilt angle between the oscillation plane and the surface before contact to the HOPG surface. This angle leads to a mixing of in-plane (horizontal) and out-of-plane (vertical) sample properties. These findings have a significant implication for the imaging process and the adjustment of the microscope and may not be ignored when interpreting frequency shift or energy dissipation measurements. To elucidate the sensitivity of the frequency modulated torsional resonance mode AFM (FM-TR-AFM) for the energy dissipation measurement, different types of samples such as a compliant material (block copolymer), a mineral (chlorite) and a macromolecule (DNA) were investigated. The measurement of energy dissipation on these specimens indicated that the TR-AFM images reveal a clear difference for the domains which have different mechanical properties. Simultaneously a topographic and a chemical contrast are obtained by recording the detuning and the dissipation signal caused by the tip-surface interaction. Using FM-TR-AFM spectroscopically, we investigated frequency shift versus distance curves on the homopolymer polystyrene (PS). Depending on the molecular weight, the frequency detuning curve displayed two distinct regions. Firstly, a rather compliant surface layer was probed; secondly, the less mobile bulk of the polymer was sensed by the oscillatory motion of the tip. The high sensitivity of this technique to mechanical in-plane properties suggests that it can be used to discriminate different chemical properties (e.g. wetting) of the material by simultaneously measuring energy dissipation and surface topography.

The central questions of this thesis are concerned with the investigation of vegetation related landsurface parameters under the impact of changing climate conditions. The spatial extent of the study is limited to the borders of the Upper Danube drainage basin, according to the requirements of the cooperative Project GLOWA-Danube (Global change of the Hydrological Cycle), funded by the German Ministry of Education and research (BMB+F). Current publications are indicating that the dynamic behaviour of the vegetation cover often is inadequately accounted for in studies that are investigating the impacts of climate change with respect to the landsurface water cycle. In order to enable a dynamic feedback between the animate land cover and the atmosphere, which might be sensitive enough to trace active reactions of the vegetation cover on changing climatic conditions, the physically based land surface process model PROMET (Process of Radiation Mass and Energy Transfer Model) was enhanced by an explicit description of the growth activity of different plant types. The introduced model approach was tested against measured data for a variety of parameters. The different validation efforts all returned good to very good results. It therefore can be stated that the model soundly demonstrated its capability concerning the precise reproduction of a variety of structural landsurface variables on different scales under observed climatic conditions. An application of the model to the calculation of climate scenarios therefore seems appropriate. In order to enable comparability with international research approaches, the internationally acknowledged global change scenarios developed by the Intergovernmental Panel on Climate Change (IPCC), are basically applied. The moderate A1B emissions scenario, which is based on the assumption of a balanced future development of different energy technologies, was selected and modified by a regional impact factor that is assumed to apply to the local situation of the Upper Danube catchment. Being applied to the regionally adapted IPCC A1B climate scenario, the model returned clear statements, projecting a possible future development of selected landsurface parameters within the Upper Danube area. Concerning the phenological behaviour of forest trees, the model simulated a strong trend towards earlier incidence of the leaf emergence of deciduous as well as of the mayshoot of coniferous trees, contributing to a significant elongation of the vegetation period. These longer phases of active growth in combination with the rising temperatures and the elevated supply of atmospheric carbon dioxide led to an increase of biological activity in the model results that manifested in increasing rates of biomass accumulation for the Upper Danube area. The increased biological activity in combination with the strong decrease of summer precipitation, which was assumed in the climate scenario, again led to an escalating frequency of drought stress events in the Upper Danube Basin. Not only the average count of water stress events per year was modelled to increase, but also a spatial extension of the regions that are affected by drought stress was mapped by the model. This general increase of water stress and the significant decrease of summer precipitation entailed a slight decline of the transpiration and evapotranspiration of the Upper Danube area in the scenario results. The modelled decline of the summer precipitation also resulted in a noticeable decrease of the modelled average discharge rates at the main gauge of the basin. The base flow rates during the summer months thereby are likely to be primarily affected. Since the model results for the scenario period featured temporal and spatial variations and standard deviations that were closely matching the statistics of the reference period, while at the same time they showed clear trends though they were avoiding extreme realizations, the scenario assumptions can be considered to be reliable. The baseline scenario, which was spot-checked for a set of reference proxels, did not return any trends as expected, indicating that the observed future trends are not of systematic origin. The further development of the introduced model approach is an appealing challenge, which might considerably contribute to the improvement of computer aided decision support systems. It can be assumed that the progress of the development of physically based models due to a more profound understanding of the processes on one hand and the sophistication and refinement of the model algorithms that result from the increase of knowledge on the other, may contribute to the development of reliable systems, that will be able to sustainably assist humanity with the handling of future environmental challenges. The author gratefully acknowledges the finacial support of the German Research Foundation (DFG) in the frame of the project "Coupled Analysis of Vegetation Chlorophyll and Water Content Using Hyperspectral, Bidirectional Remote Sensing".

Monitoring of large conservation areas has to be accomplished to fulfil the reporting commitment of the European FFH Directive. Aim of this project was to develop a new monitoring approach for area-wide mapping on a stand level. This approach was based on the combination of numerical methods in vegetation ecology with imaging spectroscopy. The study took place in the FFH conservation area Murnauer Moos, Upper Bavaria. The imagery had been gathered using the imaging spectrometer HyMap™. In order to develop maps that include spatial information on vegetation types as well as on transitions, crisp field and image classifications were combined with fuzzy methods in field and image data analysis. With Non-metric Multidimensional Scaling (NMS) ordination technique for the pre-processing of vegetation data and Partial Least Squares (PLS) regression for extrapolation, we took account of occurring mixed stands and gradual vegetation transitions. In contrast, crisp supervised image classifications are suited to assign clear categories, which are also needed in management practice. Certain emphasis was given to the different possibilities of ground data classification and endmember selection. Different applications of endmember determination to Spectral Angle Mapper (SAM) classification and Multiple Endmember Spectral Mixture Analysis (MESMA) were compared. Synthesis maps for monitoring were produced that deliver two-fold information on pixel basis: vegetation type membership on the one side, stand position in the context of the continuous field of the vegetation on the other. Hence, ecotones can be monitored within habitats. This study shows that with the use of high spatial and spectral resolution of the imagery, this information is given in the same spatial detail for a large area, and the quality of the given details is measurable.

The possibility of using accurate numerical methods to simulate seismic wavefields on unstructured meshes for complex rheologies is explored. In particular, the Discontinuous Galerkin (DG) finite element method for seismic wave propagation is extended to the rheological types of viscoelasticity, anisotropy and poroelasticity. First is presented the DG method for the elastic isotropic case on tetrahedral unstructured meshes. Then an extension to viscoelastic wave propagation based upon a Generalized Maxwell Body formulation is introduced which allows for quasi-constant attenuation through the whole frequency range. In the following anisotropy is incorporated in the scheme for the most general triclinic case, including an approach to couple its effects with those of viscoelasticity. Finally, poroelasticity is incorporated for both the propagatory high-frequency range and for the diffusive low-frequency range. For all rheology types, high-order convergence is achieved simultaneously in space and time for three-dimensional setups. Applications and convergence tests verify the proper accuracy of the approach. Due to the local character of the DG method and the use of tetrahedral meshes, the presented schemes are ready to be applied for large scale problems of forward wave propagation modeling of seismic waves in setups highly complex both geometrically and physically.

A homogeneous design for landfill bodies is generally agreed. However the manner in which waste is deposited may result in a sequence of layers that causes inhomogeneity. The goal of this research was to investigate the influences of such inhomogeneities on long-term leaching of highly soluble salts and ecotoxic species. This long-term leaching of was observed for 25 months. Laboratory column tests and field experiments (test bodies and lysimeters) were performed with municipal solid waste incineration residues. Laboratory columns were irrigated with tap water. Control field experiments were exposed to natural precipitation. Due to the fact that municipal solid waste incineration residues are continually landfilled on monofills, the percolating landfill-leachates are highly saline. Therefore extended experiments were carried out and these were treated with saline solutions: either solely or in addition to natural precipitation. Highly saline irrigation-media artificial leachates produced in the lab, actual landfill leachate or a concentrate from reverse osmosis was used, depending on the experiment. Besides irrigation, the application of residues, as the top or intermediate layers, provided continuous supply of highly saline solutions. Commonly, column experiments are conducted under water-saturated conditions. For this research however, unsaturated conditions were chosen to understand real landfill conditions. All experiments were performed as parallel experiments. One test had a uniform-grain setup and acted as a control. The application of a fine-grained bottom ash layer within a column filled mainly with coarse-grained bottom ash provided the inhomogeneous setup. Grain size changeover as a barrier layer within a column should change the permeability along the profile of the column. In some cases the barrier layer was compacted. The results of long-term the solid sample and leachate investigations pointed out that the application of a barrier layer by means of grain size changeover had mainly physical effects. With the control experiment, water contents of solid samples increased in general from the top of the experiments to the basis. In contrast, the following was observed for the application of a barrier layer:  impounding of leachate,  slowdown of leachate percolation time,  increased water retention capacity. Mainly the zone within the barrier layer showed the highest water content. A general observation was that the setting beneath the barrier layer was much drier. Another observation was that irrigation with saline water enhances water retention within the column. Additionally model experiments with plastic shots pointed out that the irrigation with small amount of water intensifies the physical effect of the barrier layer. Unsaturated water conditions which are common in landfills together with reduced permeability provide the basis for salt accumulations around the zone of the fine grained ash layer. An investigation on the distribution of the elements along the profile showed that impounding of the leachate at the barrier layer is linked to higher eluate soluble species concentrations: the tendency of accumulation was observable especially for the zone within and beneath the barrier layer and in the near-bottom samples for the control as well as extended experiments. Concerning a uniform setup the salt distribution along the profile was homogeneous up to gradual. In general the observations indicated that the application of a barrier layer by means of grain size changeover impounds the leachate. Thus, increased concentrations of different species of saline solutions in combination with changing water contents within the layers caused precipitation of the highly soluble salts out of the pore solution. The formation of salt accumulations is time-dependent. Most of the chemical and mineralogical progressions occurred only after a longer period:  tendencies for the leachate progression changed several times during the long term,  different processes depend on the pH-value (e.g. if the pH-value decreases Ca-concentrations will increase) and  this supports the vital importance of long term leaching. A main conclusion is that unsaturated conditions in combination with physical and chemical processes provide conditions conducive for salt accumulations around the zone of the barrier layer. The effects of inhomogeneities because of compaction and/or grain size changeover, as investigated in this research, furnish an explanation for actual observations at the Waldering monofill. In a particular filler part a salt horizon of several meters was encountered. This highly saline layer consists mainly of Halite and Sylvite. Hence there is the possibility that salt accumulations up to salt horizon are generated even in a humid climate. In principle the MSWI-residues afford high contents of saline species. Due to the application of a barrier layer the following advantages can be derived for landfill operations:  due to their high water retention capacity, salt accumulations cause little amounts of leachate,  high water retention capacity combined with the intensifying effect of salty crusts within the zone of the fine grained ash layer provides strong buffering concerning rainstorms.

Die vorliegende Arbeit behandelt Fragen aus dem interdisziplinären Gebiet der Nanowissenschaften durch Untersuchungen mittels Rastertunnelmikroskopie und Computerchemie. Sie steht im Kontext der Entwicklung nanotechnologischer Herstellungsverfahren, die sich auf die "bottom-up"- Fertigungsstrategie beziehen. Diese Strategie verfolgt das Ziel, aus einzelnen elementaren Bausteinen (z.B. Molekülen) grössere funktionelle Strukturen und Systeme kontrolliert zusammenzusetzen. Kern dieser Arbeit ist die Vorstellung eines neuartigen Strukturbildungsprozesses auf molekularer Ebene und die Erschliessung dessen Potentials. Für diesen Prozess wird der Begriff "supramolekulare Festphasenbenetzung" vorgeschlagen. Damit wird ausgedrückt, dass die Ergebnisse als eine neue Bedingung für supramolekulare, spontane Strukturbildung (engl. self-assembly) interpretiert werden, die bei Raumtemperatur an der Grenze zwischen zwei festen Phasen stattfindet. Das vorgestellte Modell beschreibt diesen Prozess durch Nanokristalle, die – in einer Matrix suspendiert – bei Kontakt mit einer Kristalloberfläche ein Verhalten zeigen, das trotz vorhandener Festkörpereigenschaften (kristalline Ordnung) dem Verhalten flüssiger Tropfen bei der Benetzung von Oberflächen verwandt ist. Darauf aufbauend wird das technologische Potential des neuen Prozesses erschlossen: 1. Adsorbatstrukturen von einer Reihe organischer Halbleiter werden erstmals beschrieben. Damit wird zudem gezeigt, dass sich durch supramolekulare Festphasenbenetzung unlösliche Halbleitermoleküle sehr einfach und unter Umgebungsbedingungen geordnet adsorbieren lassen – ein Ergebnis, das sonst nur mit grossen Aufwand (z.B. Molekularstrahlepitaxie im Vakuum) möglich wäre. 2. Ein Erklärungsmodell wird entwickelt, mit dem sich die bislang unverstandene Möglichkeit molekularer Datenspeicherung mittels PTCDA- Moleküle theoretisch erklären und auf weitere, unter (1) vorgestellte Moleküle erweitern lässt. 3. Die Entwicklung eines Nanofabrikationskonzeptes wird vorgestellt, das eine lokale Kontrolle des Wachstums von Nanostrukturen ermöglicht. Der Vorteil gegenüber einer klassischen, Molekül für Molekül durchgeführten Nanostrukturierung liegt darin, dass durch die Spitze eines Rastertunnelmikroskops allein die Information über Wachstumsrichtungen in das System lokal einzubringen ist, die eigentliche Bildung der Strukturen jedoch durch selbständig ablaufende und somit qualitativ und zeitlich hoche¢ziente Wachstumsprozesse stattfindet ("geführtes Wachstum"). Damit lässt sich die bisherige Beschränkung von self-assembly auf streng periodische Strukturen durchbrechen und die vordefinierte Bildung komplexer Strukturen erreichen. 4. Ein Verfahren wird vorgestellt, das eine lokale Adsorption von Molekülen zu geordneten Schichten innerhalb einer Lage fremder Moleküle erlaubt und somit den Aufbau heterogener Adsorbatschichten ermöglicht.

In this thesis I advance the integration of mineral thermodynamics into convection modeling. I have compiled a thermodynamic model of mantle mineralogy in the five component CFMAS system (CaO-FeO-MgO-Al2O3-SiO2), including mineral phases that occur close to typical chemical models of the mantle and reasonable mantle temperatures. In this system I have performed a system Gibbs free energy minimization, including pure end-member phases and a non-ideal formulation for solid solutions. Solid solutions were subdivided into discrete pseudocompounds and treated as stoichiometric phases during computation of chemical equilibrium by the simplex method. I have complemented the thermodynamic model with a model of shear wave properties [Stixrude and Lithgow-Bertelloni, 2005] to obtain a full description of aggregate elastic properties (density, bulk and shear moduli) that provide a useful basis for the consideration of seismic and geodynamic models of the Earth's mantle. By using this new thermodynamic database for the mantle I have coupled the resulting density dynamically (through the buoyancy term) with mantle convection models. I have linked the database with a high-resolution 2-D convection code (2DTERRA), dynamically coupling the thermodynamic model (density) with the conservation equations of mantle flow. The coupled model is run for different parameterisations of viscosity, initial temperature conditions, and varying internal vs. external heating. A common feature of all the models is that the convecting flow creates a characteristic discontinuity of temperature around 660 km depth in order to compensate for the entropy change due to the phase transitions. I have studied the importance and the possible consequences of such a thermal regime on the excess temperature of plumes and on the transition zone thickness. The thermodynamic mantle mineralogy model provides the conversion of the temperature field into seismic velocities so that predictions from mantle convection can be compared to seismic observations in terms of radial profiles or lateral variations. This approach allows us to predict a number of seismic observables from the convection model, all of which agree remarkably well with observations from seismic tomography.

Deterministic earthquake scenario simulations are playing an increasingly important role in seismic hazard and risk estimation. The numerical calculation of the complete 3D wavefield in the observed frequency band for a seismically active basin remains a computationally expensive task. This expense restricts seismologists either to calculating source models with homogeneous media (e.g., Gallovic and Brokesoová, 2004, 2007a,b), or to calculating single source scenario in 3D media (e.g., Olsen and Archuleta, 1996; Olsen, 2000; Ewald et al., 2006) while the complex effects of the media and the source on the ground motion are getting more and more attention. At the same time, with the development of the instrument, ground rotation introduced by an earthquake becomes a more and more important topic. Our aim is to provide a tool with which we can calculate a large number of different finite-source scenarios for a particular fault or fault system located in a 3D structure which will enable us to estimate ground motion (translation and rotation) variations due to source and 3D structure. In order to avoid having to run numerical expensive 3D code for each kinematic source scenario we propose the concept of “numerical Green’s functions” (NGF): a large seismic fault is divided into sub-faults of appropriate size for which synthetic Green’s functions at the surface of the seismically active area are calculated and stored. Consequently, ground motions from arbitrary kinematic sources can be simulated for the whole fault or parts of it by superposition. To demonstrate the functionalities of the method a strike-slip NGF data base was calculated for a simplified vertical model of the Newport-Inglewood fault in the Los Angeles basin. As a first example, we use the data base to estimate variations of surface ground motion (e.g., peak ground velocity (PGV)) due to hypocentre location for a given final slip distribution. The results show a complex behavior, with dependence of absolute PGV and its variation on asperity location, directivity effect and local under-surface structure. Hypocentral depth may affect peak ground velocity in a positive or negative way depending on the distance from the fault and the receiver location with respect to basin structure. Finite-fault source inversions reveal the spatial complexity of earthquake slip over the fault plane. In this study, several possible earthquake scenarios of Mw 7.0 are simulated with different quasi-dynamic finite source models for the Newport-Inglewood fault in the Los Angeles basin. We investigate the effects of the various slip histories on peak ground velocities and the related variations in ground motion prediction for our study area. The results confirm that the fault perpendicular components of motion are dominated by directivity effects while the fault parallel component is influenced both by the slip distribution and the basin structure. There are theoretical considerations suggesting that observations/calculations of the rotation part of earthquake-induced ground motions may provide additional information for earthquake risk hazard analysis after reports on rotational effects on structures (like twisting of tombstones or statues). For the first time, we carry out a systematic study of earthquake scenario simulations in 3D media with a specific focus on the rotational part of the motions. We simulate several M7 earthquakes with various hypocentre locations and slip histories on the Newport-Inglewood fault embedded in the 3D Los Angeles Basin. We investigate source and basin structure effects on the rotational components of ground motion (e.g., peak ground rotation rates and their variation, horizontal gradients) and compare with the effects on translations. Igel et al. (2005) shows a similarity of the observed waveforms between transverse acceleration and the vertical rotation rate in the teleseismic range benefiting from the recently developed ring laser instruments. The vertical rotation rate is found to be surprisingly similar to the horizontal translations in waveform which is explained with the plane wave propagation in the global range. That condition could not be hold any more in the near-field range, but some information could be extracted from the comparison between the translations and the rotation rate. As a final application, we investigate the source-dependent variations on rotational ground motions and compare with the results for translations. The thesis is structured as follows: Chapter 1: An insight into the present standard procedures carried out in the Seismic Hazard Assessment (SHA) is shown and then the different methodologies for predicting ground motions are described and compared, which are working individually or cooperate with each other. In recent years, one of those methods – deterministic calculations have been used widely and its consumption both in terms of CPU time and memory motivated the development of one new tool. We name that tool Numerical Green’s Function (NGF) method. Chapter 2: An introduction to the different solutions of the wave propagation is given and the state-of-the-art technologies are described. We will introduce in detail the techniques adopted. We show how to implement the source, how to solve the wave propagation problem, and how to efficiently absorb the energies outgoing from the working area, or reflect them at the free surface boundary. To correctly account for the rupture process, which has been found to be the most important contributor to the ground motion in the near-source region, different tools are developed which can be divided into two groups: kinematic description and dynamic description of the source. These two descriptions are briefly compared. Then we focus on the “quasi-dynamic” method developed by Guatteri et al. (2004) which combines, to some extent, the two different approaches. This method is used to provide us the rupture processes we will consider. Chapter 3: Green’s function stands for the response on the surface due to an impulse dislocation at the source. A large earthquake rupture can be represented with a group of impulse dislocations, and thus the ground motion on the surface can be achieved by the superposition of its Green’s functions. In this chapter, we follow the representation theorem published in Aki and Richards (2002) to give the theoretical basis of that method and briefly describe the two groups of that method: composite method and integral method. Finally we introduce our new method – Numerical Green’s Function, present the basic equations and analyze its relationship with the representation theorem and empirical Green’s function method. Chapter 4: Discretization of the fault plane into elements and assumption the source parameters identical inside each element will introduce errors in the calculated seismic motions and these errors are expected to depend on some few parameters such as the fault geometry, the rupture velocity, the sub-fault size, the cut-off frequency for low-pass filtering the ground motions, the directivity effect, etc.. In this chapter we design a hypothetic velocity structure and investigate how the errors introduced by the fault discretization will change with those parameters. The results are considered to provide some clues for our next step – selecting a seismic active fault and discretizing it into pieces with optimal sizes for which the Green’s functions will be calculated and stored. Chapter 5: The working area of this study, the Newport Inglewood fault embedded in the Los Angeles basin is introduced. The Los Angeles basin is chosen as our working area because of the high seismicity and that the most reliable information about the subsurface structure could be achieved. One active fault, the Newport-Inglewood fault inside this region is considered as a possible place where an M7.4 earthquake could happen in the future decades. Also its near vertical straight fault plane facilitates the implementation of this fault into the finite difference method. After choosing the fault and velocity structure, we re-address the optimal size of sub-fault by simulating a few M7 earthquakes and investigate the peak ground velocity and the waveform difference introduced by the different discretizations. The importance of the directivity effect on the ground motion in the near-source region has been recognized and is one of the main targets of the next generation of the attenuation relationship. A brief introduction to the physics of wave propagation is given in order to make the following discussions and illustrations of our results understandable for readers without previous knowledge. We analyze the different directivity effect supposed to happen between different component, or different kinds of motion (translation and rotation). Chapter 6: This chapter addresses the problem of the variations of surface ground motion (e.g., peak ground velocity) due to hypocentre location for a given final slip distribution. A complex behavior about the dependence of absolute PGV and its variation on asperity location, directivity effect and local structure is presented. Hypocentral depth may affect PGV in a positive or negative way depending on the distance from the fault and the location with respect to the basin structure. The directivity effect is found to control the seismic motion generation for a specific final slip distribution. Chapter 7: Inversions of the spatial and temporal evolution of earthquake slip on fault planes provide compelling evidence that fault displacement is spatially variable at all resolvable scales. Investigations of strong ground motion also indicate the spatial variability of the rupture velocity. This source physics complexity appeals for thorough description of the source process when calculating seismic motion. The method developed before hand allows efficient simulation of arbitrary slip histories. In this chapter, we investigate how the various slip histories affect peak ground velocities and the related variations in ground motion prediction for our study area. The fault perpendicular components of motion are confirmed to be dominated by directivity effects while the fault parallel component is influenced both by the slip distribution and the basin structure. Chapter 8: The rotational motions excited by earthquakes are believed to be capable of providing more information for the aim of earthquake hazard analysis. But to the present time, those information are hard to be acquired. The first reason is that the spacing of the accelerograph recording sites is too large to get the indirect rotational motion measurement from the accelerograph recordings. The second reason is that the small amplitude of the rotational motion is beyond the recording capability of the present instruments. At the present time, the answers lie in the numerical simulation. In this section, for an M7.0 earthquake which is considered to happen on the Newport-Inglewood fault embedded in the Los Angeles basin, different parameters responsible for the ground rotation variation, like the hypocentre location, directivity effect and slip history, are systematically investigated. In the teleseismic range where plane wave assumption can be made, Igel et al. (2005) investigates the relationship between the translation and the rotation in terms of the amplitude ratio and waveform similarity. In this section, we find the waveform similarity between one horizontal acceleration and the vertical rotation rate even in the near-source region. We also calculate the amplitude ratio between the acceleration and the rotation rate and compare the results with the medium properties. That ratio is found to be somehow correlative to the basin depth. Chapter 9: The most important results in this work are briefly summarized. Future promising prospectives are also described. Appendix A: The individual peak ground velocity distributions corresponding to the varying hypocentres of the grid presented in chapter 6 are presented as a table for better illustration in case of interest. Three components of velocity and rotation rates are summarized here. Appendix B: The peak ground velocity distributions are grouped into different tables corresponding to the varying slip histories (chapter 7). Three components of velocity and rotation rate are summarized here.