Seismic modeling is a technique for simulating wave propagation through the subsurface. For a given geological model, seismic modeling allows us to generate snapshots of wave propagation and synthetic data. In my dissertation, for real seismic events I have chosen to implement the finite-difference modeling technique. When adequate discretization in space and time is possible, the finite-difference technique is by far one of the most accurate tools for simulating elastic-wave propagation through complex geological models. In recent years, a significant amount of work has been done in our group using 2D finite-difference modeling. For complex salt structures which exploration and pro- duction industries meet today, 2D finite-difference modeling is not sufficient to study subsalt imaging or the demultiple of subsalt models. That is why I have developed a 3D finite-difference modeling code. One of the key challenges that I have met in developing the 3D finite-difference code is to adapt the absorbing boundary conditions. Absorbing boundary conditions are needed to describe the infinite geological models by limited computing domain. I have validated the 3D finite-difference code by comparing its results with analytic solutions. I have used 3D finite-difference program to generate data corresponding to 3D complex model which describes salt and subsalt structures of Gulf of Mexico. The resulting data include reflections, diffractions and other scattering phenomena. I have also used finite-difference program in anisotropic context to show that we can effectively predict shear-wave splitting and triplication in the data. There are new sets of events that are not directly recorded in seismic data, they have been called virtual events. These events are turning to be as important as real events in modern data processing. Therefore we also have to learn how to model them. Unfortunately, they cannot yet be modeled directly from finite-difference. Here I will describe how to model these events by using cross correlation type representation theorem. As illustration of how important of virtual events for seismic data process- ing, I also described an internal multiple attenuation technique which utilized virtual events.

Tourism industry is one of the hardest hits by the COVID-19 pandemic outbreak, Event industry as an important stakeholder of tourism has been fiercely damaged globally. In this study the impact of COVID-19 pandemic on the event industry businesses in Sweden, their methods of coping with this situation and the recovery plans will be evaluated. Further some predictions about the future trends and possible transformations of the industry have been made. This research has been conducted qualitatively and by gathering data from both primary and secondary sources provided a very broad reference for the researcher. Restrictions in Sweden started with a 500-person limit then the figures went down to 50 people, followed by 8 people, afterwards 300 and finally 8 people limit again. Commercially, it has been difficult to conduct business due to the massive uncertainty brought on by COVID-19 for all the companies in the event industry in Sweden. Cancelling or postponing events caused huge revenue losses, redundancies, closing businesses etc. limitations and uncertainties brought by COVID-19 pandemic forced some innovative companies to start rethinking their event packages. By upskilling staff and digital investing in building the needed infrastructures, many event companies could step into the virtual and hybrid events landscape. Meanwhile , Small to medium-sized companies suffered the most in terms of tackling the situation due to limited resources and severity of the situation. The forceful hiatus to hold-on till going back to normal has been the best solution for those who were not able to come up with coping strategies. Clearly by the mass vaccine distribution, the event industry will gradually go back to its normal status quo, while virtual on demand and hybrid events will stay as important components of the industry.The result of this study reveals the value of resiliency and being prepared that will help companies to survive during crisis situations. But after all, although this pandemic is a disruption that caused many challenges for the event industry. But, at the same time it brought many dynamic opportunities for the sector to slowly evolve and develop.

This research was conducted to find out more about the willingness to pay for online concerts both during the Covid-19 pandemic and in the future. Secondary data was collected in form of literature in order to perform primary research. The primary research consisted of a quantitative online survey to collect data on a specific case study, which covered an online concert by the German band Feuerschwanz in the beginning of 2021. The research picked up the connection between concerts and tourism, the concert experience as well as co-creation, the relevance of onlinec oncerts and willingness to pay as central themes. To analyze the data, descriptive and inferential statistics were used to find potential trends and differences. In the findings it could be seen that online concerts are commonly appreciated and have a future prospect. Further, it was seen that both material and non-material elements can enhance the willingness to pay for online concerts and that the major reasons for attending online concerts are being a fan and the lack of live concerts during the pandemic. This research successfully contributed to fill a research gap that is existing due to the only recent emergence of online concerts in this scope. It can further be used to help artists and organizers when planning online concerts, and it gives a perspective about a possible future that includes online concerts.