Hardware-aware block size tailoring on adaptive spacetree grids for shallow water waves.

Spacetrees are a popular formalism to describe dynamically adaptive Cartesian grids. Though they directly yield an adaptive spatial discretisation, i.e. a mesh, it is often more efficient to augment them by regular Cartesian blocks embedded into the spacetree leaves. This facilitates stencil kernels working efficiently on homogeneous data chunks. The choice of a proper block size, however, is delicate. While large block sizes foster simple loop parallelism, vectorisation, and lead to branch-free compute kernels, they bring along disadvantages. Large blocks restrict the granularity of adaptivity and hence increase the memory footprint and lower the numerical-accuracy-per-byte efficiency. Large block sizes also reduce the block-level concurrency that can be used for dynamic load balancing. In the present paper, we therefore propose a spacetree-block coupling that can dynamically tailor the block size to the compute characteristics. For that purpose, we allow different block sizes per spacetree node. Groups of blocks of the same size are identied automatically throughout the simulation iterations, and a predictor function triggers the replacement of these blocks by one huge, regularly rened block. This predictor can pick up hardware characteristics while the dynamic adaptivity of the fine grid mesh is not constrained. We study such characteristics with a state-of-the-art shallow water solver and examine proper block size choices on AMD Bulldozer and Intel Sandy Bridge processors

Simulation Of Generation, Propagation And Runup Due To The 26 December 2004 Andaman Tsunami.

Tsunami Andaman 26 Disember 2004 telah membawa kesengsaraan kepada komuniti yang tinggal di kawasan persisiran pantai yang terjejas. The 26 December 2004 Andaman tsunami has resulted in much suffering among affected coastal communities

Seismic Risk Analysis of Revenue Losses, Gross Regional Product and transportation systems.

Natural threats like earthquakes, hurricanes or tsunamis have shown seri- ous impacts on communities. In the past, major earthquakes in the United States like Loma Prieta 1989, Northridge 1994, or recent events in Italy like L’Aquila 2009 or Emilia 2012 earthquake emphasized the importance of pre- paredness and awareness to reduce social impacts. Earthquakes impacted businesses and dramatically reduced the gross regional product. Seismic Hazard is traditionally assessed using Probabilistic Seismic Hazard Anal- ysis (PSHA). PSHA well represents the hazard at a specific location, but it’s unsatisfactory for spatially distributed systems. Scenario earthquakes overcome the problem representing the actual distribution of shaking over a spatially distributed system. The performance of distributed productive systems during the recovery process needs to be explored. Scenario earthquakes have been used to assess the risk in bridge networks and the social losses in terms of gross regional product reduction. The proposed method for scenario earthquakes has been applied to a real case study: Treviso, a city in the North East of Italy. The proposed method for scenario earthquakes requires three models: one representation of the sources (Italian Seismogenic Zonation 9), one attenuation relationship (Sa- betta and Pugliese 1996) and a model of the occurrence rate of magnitudes (Gutenberg Richter). A methodology has been proposed to reduce thou- sands of scenarios to a subset consistent with the hazard at each location. Earthquake scenarios, along with Mote Carlo method, have been used to simulate business damage. The response of business facilities to earthquake has been obtained from fragility curves for precast industrial building. Fur- thermore, from business damage the reduction of productivity has been simulated using economic data from the National statistical service and a proposed piecewise “loss of functionality model”. To simulate the economic process in the time domain, an innovative businesses recovery function has been proposed. The proposed method has been applied to generate scenarios earthquakes at the location of bridges and business areas. The proposed selection method- ology has been applied to reduce 8000 scenarios to a subset of 60. Subse- quently, these scenario earthquakes have been used to calculate three system performance parameters: the risk in transportation networks, the risk in terms of business damage and the losses of gross regional product. A novel model for business recovery process has been tested. The proposed model has been used to represent the business recovery process and simulate the effects of government aids allocated for reconstruction. The proposed method has efficiently modeled the seismic hazard using scenario earthquakes. The scenario earthquakes presented have been used to assess possible consequences of earthquakes in seismic prone zones and to increase the preparedness. Scenario earthquakes have been used to sim- ulate the effects to economy of the impacted area; a significant Gross Regional Product reduction has been shown, up to 77% with an earthquake with 0.0003 probability of occurrence. The results showed that limited funds available after the disaster can be distributed in a more efficient way

Analysis of Tsunami Resonance in Coastal Waters

Recently, extreme tsunami waves generated by submarine earthquake have caused tremendous damages to the coastal cities and ports. Strong seiche oscillations and runups are observed in specific sea areas around the world. When multiple destructive tsunamis caused damage to Japan, Chile, USA, Indonesia, New Zealand, they have been recognized as a potential hazard to Korean coastal communities. Although no frequent impacts to the coast of Korean peninsula, there were some important events in the east of Korea in the past. This study focuses on two historical events and recalculate with different fault and rupture mechanism for prediction considering the recent trend of submarine earthquake. Three-dimensional, time dependent, nonlinear, incompressible, viscous flow calculations were performed of realistic models of tsunami waves interacting with continental slopes and shelves. The present study of the 1983 Akita tsunamis demonstrates the multi-scale resonance along continental coasts. Together with the Nankai tsunami for inland sea, we have confirmed the inland sea resonance surrounded by islands in defining the impact along the coast. The damping action of submerged barriers on tsunami waves was investigated. Significant amounts of the energy of a tsunami were reflected by submerged barriers or coastal boundaries. Coherence and wavelet analyses for deducing a predominant period and time frequency are useful in reasoning the inundation. The resonance modes, which are largely independent of the tsunami source, allow identification of at-risk communities and infrastructure for mitigation of tsunami hazards. The numerical simulation of tsunami waves can provide realistic descriptions of their propagation. Furthermore, understanding of the resonance and the predicted runups for the site of power plant and industrial complex in the east coast of Korea would allow better preparation for the future disasters.Contents ABSTRACT LIST OF TABLES LIST OF FIGURES Chapter1 Introduction 1.1 Background and Objectives 1.2 Major Tsunami Disasters in Korea-Japan Sea Chapter 2 Tsunami Charateristics 2.1 Basic Description 2.2 Excitation of Tsunami Chpater 3 Numerical Simulation 3.1 Governing Equations 3.2 Spherical Coordinate System Model 3.3 Cartesian Coordinate System Model Chapter 4 Resonance Analysis 4.1 Open Coast Analysis 4.2 Inland Sea Analysis Chapter 5 Result and Discussions Reference

Tsunami Hazard Assessment: Best Modeling Practices and State-of-the-Art Technology

NUREG/CR-722

Numerical Studies Of Tectonic And Landslide-Generated Tsunamis Caused By The 1964 Great Alaska Earthquake

Thesis (Ph.D.) University of Alaska Fairbanks, 2011The focus of my thesis is on the complex source mechanism of tsunami waves generated by the MW9.2 1964 Alaska earthquake, the largest instrumentally recorded earthquake in North America. The vertical seafloor displacements produced a trans-Pacific tectonic tsunami that caused loss of life and great damage in Alaska and the west coast of the United States and Canada. In addition to the major tectonic wave, about 20 local tsunamis were generated by submarine mass failures in a number of bays and fjords in south-central Alaska. These locally generated waves caused most of the damage and accounted for 76% of tsunami fatalities. I use numerical modeling to study tectonic and landslide tsunamis of the 1964 earthquake. The first part of the thesis presents numerical analysis of tsunami inundation at Seward and other locations in Resurrection Bay caused by the combined impact of landslide-generated waves and the tectonic tsunami. This study utilizes the recent geological findings of large-scale submarine slope failures in the bay during the 1964 earthquake and confirms the hypothesis that tsunami waves observed in Seward during and immediately after the earthquake resulted from multiple underwater landslides. The analysis of the simulated composite inundation area caused by the two different tsunami sources explains their relative contributions and demonstrates good agreement with observations. The second major topic is the source of the 1964 tectonic tsunami. The results of inundation modeling in Kodiak Island show that tsunami runup in the near field strongly depends on coseismic slip in the Kodiak asperity. I test the hypothesis that splay faults played a major role in tsunami generation and evaluate the extent of the Patton Bay fault using near-field tsunami observations. The new source function of the 1964 tsunami is presented, which includes the effects of the splay fault displacements and the component of the vertical deformation of the sea surface due to horizontal displacements on the megathrust. The results of numerical modeling studies included in this thesis complement the Alaska Tsunami Inundation Mapping Project. This activity provides emergency officials in coastal Alaska with tsunami hazard assessment tools and helps mitigate future tsunami risk

Tsunami Hazard Assessment: Best Modeling Practices and State-of-the-Art Technology

NUREG/CR-722

EXPERIMENTAL AND COMPUTATIONAL ACTIVITIES AT THE OREGON STATE UNIVERSITY NEES TSUNAMI RESEARCH FACILITY

A diverse series of research projects have taken place or are underway at the NEES Tsunami Research Facility at Oregon State University. Projects range from the simulation of the processes and effects of tsunamis generated by sub-aerial and submarine landslides (NEESR, Georgia Tech.), model comparisons of tsunami wave effects on bottom profiles and scouring (NEESR, Princeton University), model comparisons of wave induced motions on rigid and free bodies (Shared-Use, Cornell), numerical model simulations and testing of breaking waves and inundation over topography (NEESR, TAMU), structural testing and development of standards for tsunami engineering and design (NEESR, University of Hawaii), and wave loads on coastal bridge structures (non-NEES), to upgrading the two-dimensional wave generator of the Large Wave Flume. A NEESR payload project (Colorado State University) was undertaken that seeks to improve the understanding of the stresses from wave loading and run-up on residential structures. Advanced computational tools for coupling fluid-structure interaction including turbulence, contact and impact are being developed to assist with the design of experiments and complement parametric studies. These projects will contribute towards understanding the physical processes that occur during earthquake generated tsunamis including structural stress, debris flow and scour, inundation and overland flow, and landslide generated tsunamis. Analytical and numerical model development and comparisons with the experimental results give engineers additional predictive tools to assist in the development of robust structures as well as identification of hazard zones and formulation of hazard plans

Earthquake Early Warning System (EEWs) for the New Madrid Seismic Zone

Part 1: Research in the last decade on Earthquake Early Warning Systems (EEWSs) has undergone rapid development in terms of theoretical and methodological advances in real time data analysis, improved telemetry, and computer technology and is becoming a useful tool for practical real time seismic hazard mitigation. The main focus of this study is to undertake a feasibility study of an EEWS for the New Madrid Seismic Zone (NMSZ) from the standpoint of source location. Magnitude determination is addressed in a separate paper. The NMSZ covers a wide area with several heavily populated cities, vital infrastructures, and facilities located within a radius of less than 70 km from the epicenters of the 1811-1812 earthquakes. One of the challenges associated with the NMSZ is that while low to moderate levels of seismic activity are common, larger earthquakes are rare (i.e. there are no instrumentally recorded data for earthquakes with magnitudes greater than M5.5 in the NMSZ). We also recognize that it may not be realistic to provide early warning for all possible sources as is done on the west coast U.S. and we therefore focus on a specific source zone. We examine the stations within the NMSZ in order to answer the question What changes should be applied to the NMSZ network to make it suitable for earthquake early warning (EEW). We also explore needed changes to the Advanced National Seismic System (ANSS) Earthquake Monitoring System Real Time (AQMS RT) data acquisition system to make it useful for EEW. Our results show that EEW is feasible, though several technical challenges remain in incorporating its use with the present network.Part 2: Increasing vulnerability of metropolitan areas within stable continental regions (SCR), such as Memphis, TN and St. Louis, MO near the New Madrid Seismic Zone (NMSZ), to earthquakes and the very low probability level at which short term earthquake forecasting is possible make an earthquake early warning system (EEWS) a viable alternative for effective real-time risk reduction in these cities. In this study, we explore practical approaches to earthquake early warning (EEWS), and test the adaptability and potential of the real-time monitoring system in the NMSZ. We determine empirical relations based on amplitude and frequency magnitude proxies from the initial four seconds of the P-waveform records available from the Cooperative New Madrid Seismic Network (CNMSN) database for magnitude ????\u3e2.1. The amplitude-based proxies include low pass filtered peak displacement (Pd), peak velocity (Pv), and integral of the velocity squared (IV2), whereas the frequency-based proxies include predominant period (????????), characteristic period (????????), and log average period (????????????????). Very few studies have considered areas with lower magnitude events. With an active EEW system in the NMSZ, damage resulting from the catastrophic event, as witnessed in 1811-1812, may be mitigated in real-time