Tsunamis are one of the most catastrophic natural hazards that can devastate coastal regions. Most common mechanisms that generate tsunamis are undersea earthquakes and submarine landslides. However, in enclosed basins, such as fjords, reservoirs, and lakes, subaerial landslides can also generate devastating tsunamis with similar or worse consequences, because of a more efficient wave generation. Here, we present the validation of a three-dimensional (3D) numerical model, TSUNAMI3D, by comparing numerical results with a set of subaerial landslide laboratory experiments carried out in the large tsunami wave basin at the Oregon State University (OSU). Results obtained from the laboratory experiments show that subaerial landslides generate highly non-linear waves with complex wave patterns and runup, challenging existing numerical models. The 3D numerical model is first verified with a commercial code, FLOW3D, to obtain a compromise between the model’s spatial-time resolution accuracy and computational cost. Second, the 3D numerical model and the commercial code are validated with a set of OSU laboratory experiments comprising three different layouts or basin configurations, namely, fjord, curved headland, and basin-wide. Simplified material rheology and key parameters required for modeling subaerial landslides are defined. Numerical models’ relative errors are estimated and analyzed, and the models’ limitations are discussed. In general, numerical models’ relative errors are found to be acceptable in most of the validation tests except those tests located close to the wave generation region. Validation results confirm that the 3D numerical models with simplified landslide rheology can be used to understand and reproduce the complex non-linear wave propagation and runup generated by subaerial landslides. Thus, TSUNAMI3D can help assess tsunami hazards in communities located in proximity to potential subaerial landslides. Also, the set of physical experiments can be used for further numerical validation efforts, helping tsunami organizations, e.g., the National Tsunami Hazard Mitigation Program, to amend existing or develop better numerical models and thus, improve inundation/evacuation mapping products that would save lives and property.

This paper describes a fast non-linear shallow water solver (NSW) on a grid comprising of cells of various shapes. The NSW model is solved using a positivity preserving, finite volume based shock capturing algorithm. Temporal calculations use the TVD (Total Variation Diminishing) 2 nd order Runge-Kutta explicit scheme. The solver accurately preserves the steady “C” state of the NSW model. The NSW solver is implemented on the GPGPUs (General-Purpose computing on Graphical Processing Units) using Nvidia’s CUDA (Compute Unified Device Architecture) programming library. The model has been successfully verified and validated against analytical, experimental and field cases. The model can be used for simulating tsunami simulations on telescoping grids, fluvial and pluvial floods, storm surge inundations and dam break flooding with a variety of mixed shape grids

Landslides of subaerial and submarine origin may generate tsunamis with locally extreme amplitudes and runup. While the landslides themselves are dangerous, the hazards are compounded by the generation of tsunamis along coastlines, in enclosed water bodies, and off continental shelves and islands. Tsunamis generated by three-dimensional deformable granular landslides were studied on planar and conical hill slopes in the three-dimensional NEES tsunami wave basin at Oregon State University based on the generalized Froude similarity. A unique pneumatic landslide tsunami generator (LTG) was deployed to control the kinematics and acceleration of the naturally rounded river gravel and cobble landslides to simulate broad ranges of landslide shapes and velocities along the slope. Lateral and overhead cameras are used to measure the landslide shapes and kinematics, while acoustic transducers provide the shape of the subaqueous deposits. The subaerial landslide shape is extracted from the camera images as the landslide propagates under gravity down the hill slope, and surface reconstruction of the landslide is conducted using the stereo particle image velocimetry (PIV) system on the conical hill slope. Subaerial landslide surface velocities are measured with a planar PIV system on the planar hill slope and stereo PIV system on the conical hill slope. The submarine deposits are characterized by the runout distances and the deposit thickness distributions. Larger cobbles are observed producing hummock type features near the maximum runout length. These unique laboratory landslide experiments serve to validate deformable landslide models as well as provide the source characteristics for tsunami generation.

On 12 January 2010, a magnitude M w 7.0 earthquake occurred 25 km west–southwest of Haiti’s capital Port-au-Prince causing an estimated 316,000 fatalities, thereby exceeding any previous loss of life from a similar size earthquake. In addition, tsunami waves triggered by the earthquake caused at least three fatalities at Petit Paradis due to a complete lack of tsunami awareness. The International Tsunami Survey Team (ITST) was deployed within weeks of the event and covered the greater Bay of Port-au-Prince and more than 100 km of Hispaniola’s southern coastline. The collected survey data include more than 21 tsunami heights along with observations of coastal land level change. Maximum tsunami heights of 3 m have been measured for two independently triggered tsunamis.

[1] In the paper ‘‘Physical modeling of tsunamis generated by three-dimensional deformable granular landslides’’ by Mohammed and Fritz (Journal of Geophysical Research, 117, C11015, doi: 10.1029/ 2011JC007850, 2012), the exponent of the landslide Froude number appearing in equation (3f) was printed incorrectly; i.e., the minus sign had been omitted. The correct form of the equation that defines the attenuation rate for the second wave crest amplitude of the tsunami wave generated by deformable granular landslide is given in equation (3f).

On March 11, 2011, a magnitude Mw 9.0 earthquake occurred off the coast of Japan's Tohoku region causing catastrophic damage and loss of life. The tsunami flow velocity analysis focused on two survivor videos recorded from building rooftops at Kesennuma Bay along Japan's Sanriku coast. A terrestrial laser scanner was deployed at the locations of the tsunami eyewitness video recordings. The tsunami current velocities through the Kesennuma Bay are determined in a four step process. The LiDAR point clouds are used to calibrate the camera fields of view in real world coordinates. The motion of the camera during recordings was determined. The video images were rectified with direct linear transformation. Finally a cross‐correlation based particle image velocimetry analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields. The measured maximum tsunami height of 9 m in the Kesennuma Bay narrows were followed by maximum tsunami outflow currents of 11 m/s less than 10 minutes later.

Tsunamis generated by deformable granular landslides are physically modeled in a three‐dimensional tsunami wave basin based on the generalized Froude similarity. The dynamic landslide impact characteristics were controlled by means of a novel pneumatic landslide generator. The wave amplitudes, periods, and wavelengths are related to the landslide parameters at impact with the landslide Froude number being a dominant parameter. Between 1 and 15% of the landslide kinetic energy at impact is converted into the wave train energy. The wave amplitudes decay in radial and angular directions from the landslide axis. The first wave crest mostly travels with speeds close to the theoretical approximation of the solitary wave speed. The measured tsunami wave profiles were either of the nonlinear oscillatory or nonlinear transition type depending primarily on the landslide Froude number and relative slide thickness at impact. The generated waves range from shallow to deep water depth regimes, with the majority being in the intermediate water depth regime. Wave characteristics are compared with other two‐ and three‐dimensional landslide tsunami studies and the results are discussed.

Landslide generated tsunamis are particularly hazardous in enclosed water bodies. Topographical and bathymetric features can either dissipate or enhance the generated waves leading to potentially extensive damages. To study the effect of such features landslide generated tsunami experiments were conducted in physical scale models representing fjords, headlands and farfield hill slopes. A pneumatic landslide tsunami generator deploys unconfined deformable granular landslides on a hill slope which impact the water surface and thereby generate tsunami waves. The instrumentation setup includes multiple cameras, particle image velocimetry, acoustic transducers and an array of wave gauges. Landslide measurements are made to characterize the source properties. The wave profile recordings with and without the topographic features provide insights into their effects on the tsunami wave characteristics. A fjord setup traps and distributes the wave energy along the fjord slopes in the channel, while a headland captures only part of the energy and radiates the rest into the open basin.

On 12 January 2010 a magnitude Mw 7.0 earthquake occurred 25 km west-southwest of Haiti's Capital of Port-au-Prince, which resulted in more than 230,000 fatalities thereby more than doubling any previous loss of life from a similar size earthquake. In addition tsunami waves triggered by the earthquake caused at least 3 fatalities at Petit Paradis. The international tsunami survey team (ITST) was deployed within days of the event and covered the greater Bay of Port-au-Prince and more than 100 km of Hispaniola's southern coastline. Field observations are compared to numerical modeling results.

Subaerial and submarine landslides can trigger tsunamis with locally high amplitudes and runup, which can cause devastating effects in the near field region such as the 1958 Lituya bay, Alaska, 1998 Papua New Guinea and 2006 Java tsunamis. Tsunami generation by submarine and subaerial landslides were studied in the three dimensional NEES (George E. Brown, Jr. Network for Earthquake Engineering Simulation) tsunami wave basin (TWB) at Oregon State University based on the generalized Froude similarity. A novel pneumatic landslide generator was deployed to control the granular landslide geometry and kinematics. Measurement techniques such as particle image velocimetry (My), multiple above and underwater video cameras, multiple acoustic transducer arrays (MTA), as well as resistance wave and runup gauges were applied. The experimental data provided new insights on landslide deformation as it impacts the water surface, penetrates the water and finally deposits on the bottom of the basin. The influence of the landslide volume, shape and the impact speed on the generated tsunami waves were extensively studied. The instantaneous surface velocity fields measured using the PIV gave insight into the kinematics of the landslide and wave generation process. At high impact velocities, flow separation occurred on the slide shoulder resulting in a hydrodynamic impact crater. The measured wave profiles yielded information on the wave propagation and attenuation. The measured wave speed of the leading wave reaches the theoretical solitary wave celerity while the trailing waves are slower in nature. Attenuation functions of the leading wave crest amplitude, the wave length and the time period were obtained to study the wave behavior in the near field and far field regions. The measured wave data serves the validation and advancement of 3-dimensional numerical landslide tsunami and prediction models.

On July 10, 1958, an earthquake M-w 8.3 along the Fairweather fault triggered a major subaerial landslide into Gilbert Inlet at the head of Lituya Bay on the southern coast of Alaska. The landslide impacted the water at high speed generating a giant tsunami and the highest wave runup in recorded history. The mega-tsunami runup to an elevation of 524 m caused total forest destruction and erosion down to bedrock on a spur ridge in direct prolongation of the slide axis. A cross section of Gilbert Inlet was rebuilt at 1:675 scale in a two-dimensional physical laboratory model based on the generalized Froude similarity. A pneumatic landslide tsunami generator was used to generate a high-speed granular slide with controlled impact characteristics. State-of-the-art laser measurement techniques such as particle image velocimetry (PIV) and laser distance sensors (LDS) were applied to the decisive initial phase with landslide impact and wave generation as well as the runup on the headland. PIV provided instantaneous velocity vector fields in a large area of interest and gave insight into kinematics of wave generation and runup. The entire process of a high-speed granular landslide impact may be subdivided into two main stages: (a) Landslide impact and penetration with flow separation, cavity formation and wave generation, and (b) air cavity collapse with landslide run-out and debris detrainment causing massive phase mixing. Formation of a large air cavity - similar to an asteroid impact - in the back of the landslide is highlighted. A three-dimenional pneumatic landslide tsunami generator was designed, constructed and successfully deployed in the tsunami wave basin at OSU. The Lituya Bay landslide was reproduced in a three-dimensional physical model at 1:400 scale. The landslide surface velocities distribution was measured with PIV. The measured tsunami amplitude and runup heights serve as benchmark for analytical and numerical models.