role of narrow mountains in large scale organization of asian monsoon convection abstract the asian summer monsoon is organized into distinct convection centers but the mechanism for this organization is not well understood analysis of new satellite observations reveals that narrow mountain ranges are an important organizing agent anchoring monsoon convection centers on the windward side the bay of bengal convection in particular features the heaviest precipitation on its eastern coast because of orographic lifting as the southwest monsoon impinges on the coastal mountains of myanmar also known as burma this is in contrast to the widely held view that this convection is centered over the open ocean as implied by coarse resolution datasets a view that would require an entirely different explanation for its formation narrow in width and modest in height 1 km these mountains are hardly mentioned in conceptual depictions of the large scale monsoon and poorly represented in global climate models the numerical simulations of this study show that orographic rainbands are not a

runup of granular landslide generated tsunamis on planar coasts and conical islands large scale physical model experiments of tsunamis generated by granular landslides and volcanic flank collapses are conducted to study the wave runup on both the hill slope laterally adjacent to the landslide and an opposing hill slope a pneumatic landslide tsunami generator was deployed on planar and convex conical hill slopes to simulate deformable landslides with various geometries and kinematics on the landslide hill slope maximum runup and rundown were observed in the landslide impact region followed by adjacent second maxima after the lateral waves were fully formed the runup and rundown decayed asymptotically from the second maxima in the conical island scenario a localized runup amplification was measured on the lee side of the island outside the landslide impact region the effects of the landslide granulometry on the lateral wave runup are minimal the lateral wave runup on the planar hill slope was generally larger than on the convex conical hill slope outside the landslide impact region the convex conical hill slope traps less lateral wave energy the zeroth mode of the edge wave dispersion relation matched the first and second lateral waves on the planar hill slope and the first wave on the convex conical hill slope predictive equations for the laterally propagating wave characteristics are derived and a method to predict the runup on an opposing hill slope is presented the predictive wave and runup equations are benchmarked against the 2007 landslide generated tsunami in chehalis lake british columbia canada

landslide generated tsunamis runup at the coast of a conical island new physical model experiments 1 this paper presents new physical model experiments on tsunamis generated by landslides at the coast of a conical island the experiments have been carried out in a large wave tank the radius of the island coastline and the falling height of the landslide have been varied during the experimental campaign the landslide is reproduced by a solid body shaped as a half of an ellipsoid tsunami runup is measured using special wave gauges a detailed analysis of the runup along the coastline is presented with special attention to the role of each wave in the packet and to the evolution of the envelope of the first group of waves

twin tsunamis triggered by the 12 january 2010 haiti earthquake 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

a numerical study of the run up generated by three dimensional landslides 1 a large set of numerical experiments are designed to examine the maximum run up generated by three dimensional 3 d submerged and subaerial solid body landslides a depth integrated numerical model is utilized allowing for the efficient simulation of landslides in shallow and intermediate water six dimensionless parameters are introduced the slide thickness the slide wave number a slide shape parameter the horizontal aspect ratio of the slide the specific gravity of the slide mass and the slope of the beach six sets of simulations are first presented wherein one of the six dimensionless parameters are singularly varied this allows for the identification of parameter dependence on maximum run up after combining the dependencies a number of relationships appear most notably a very clear division between the near and far field is observed where here the far field is defined as the region displaced from the projection of the landslide on the nearby beach where edge waves may dominate the wave pattern for submerged slides a nondimensional estimation of the maximum run up just landward of the slide is found as well as the location and magnitude of the secondary run up peak this secondary peak is due to the propagation of edge waves and is in some cases larger than the peak immediately landward of the slide the results presented in this paper may be useful for preliminary hazard assessment where a simple and quick estimation of the maximum run up height and locations are required additionally the formulas developed will be particularly beneficial to those developing 3 d landslide experiments

on the effect of the water body geometry on landslide tsunamis physical insight from laboratory tests and 2d to 3d wave parameter transformation preliminary landslide tsunami hazard assessment is commonly based on empirical equations derived from wave channel 2d or wave basin 3d experiments the far field wave in 2d can easily be an order of magnitude larger than in 3d the present study systematically investigates the effect of the water body geometry on the wave characteristics in the near and far field subaerial landslide tsunami tests were conducted relying upon both a 2d and a 3d physical model undertaken with identical boundary conditions the test parameters included two water depths three rigid slides as well as various slide release positions empirical equations for 3d offshore and laterally onshore wave properties are presented and compared with previous work a direct comparison of the wave features reveals that the waves decay in 2d 3d onshore and 3d offshore with x 0 30 r 0 67 and r 1 0 where x 2d and r 3d describe the distance from the impact zone in 2d four wave types are observed whereas only the two least non linear types were observed in 3d this finding is further analysed with wavelet spectra for a large slide froude number f relative slide thickness s and relative slide mass m the 3d wave heights in the slide impact zone can be as large as in 2d however for small f s and m the 3d waves are considerably smaller both in the near and far field a novel method is presented and validated to transform data from 2d studies to 3d this method may have favourable implications on preliminary landslide tsunami hazard assessment

shelf resonance and impact of near field tsunami generated by the 2010 chile earthquake 1 the 2010 chile earthquake of mw 8 8 generated a destructive tsunami in the near field that resulted in warnings across the pacific numerical modeling shows trapping and amplification of the energy over the continental shelf and slope a spectral analysis of the computed surface elevation reveals resonance oscillations with periods up to 129 min along the central chile coast the temporal and spectral data provides an explanation for the long period waves recorded by dart buoys and the prolonged wave activities and belated impacts reported by residents and survey teams the present study of the 2010 chile tsunami together with those of the 2006 kuril and 2009 samoa tsunamis has directly associated shelf resonance with impacts on insular and continental coasts and provided a tool to identify at risk localities in tsunami hazard assessment

offshore propagation of coastal precipitation abstractthis work focuses on the seaward propagation of coastal precipitation with and without mountainous terrain nearby offshore of india diurnal propagation of precipitation is observed over the bay of bengal on the eastern side of the bay a diurnal but nonpropagating signal is observed near the west coast of burma this asymmetry is consistent with the inertio gravity wave mechanism perturbations generated by diurnal heating over the coastal mountains of india propagate offshore amplify in the upwind direction and dissipate in the downwind direction relative to the steering wind owing to critical level considerations a linear model is applied to evaluate sensitivity to gravity waves as these affect deep moist convection and propagation analyses are performed for various heating depths mountain widths stability coriolis effect background mean wind and friction calculations reveal how these factors affect the amplitude dissipation initiation phase and propagation speed of the diurnal

bottom stress estimates from vertical dissipation rate profiles on the continental shelf abstract measurements of the near bottom distribution of the turbulent dissipation rate on the continental shelf west of vancouver island are used to calculate bottom stress a free failing vertical profiler with microstructure shear probes was used to measure the dissipation rate from near the surface to within 0 15 m of the bottom the shear probes measure velocity gradients at scales within the viscous subrange of the turbulence and therefore directly measure the rate at which kinetic energy is dissipated by viscosity friction velocities are computed from the formula uast z where the dissipation rate is measured in the constant stress layer the technique is more reliable than estimates of the dissipation rate obtained by fitting spectral slopes to velocity spectra at scales in the inertial subrange near bottom current measurements indicate that the bottom stress values obtained from the turbulent measurements are well correlated with the current magnitude an estimate of the drag coeff

three dimensional experiments on landslide generated waves at a sloping coast abstract this paper describes new three dimensional experiments on water waves generated by landslides the landslide is reproduced by a rigid elliptical body sliding along an inclined plane slope of 1 3 1 vertical 3 horizontal the generated water waves are free to propagate both offshore and alongshore since the plan dimensions of the used wave tank are of at least one order of magnitude larger than the width of the landslide which can be considered to be a scale of the wave length the experimental study has been carried out reproducing both subaerial and partially submerged landslides the wave generation process is studied by means of video records of the near field flow and measurement of the landslide movement the properties of the waves propagating along the coast are described on the basis of runup gauges the waves observed during the experiments always present first a crest and then a trough as the first wave propagates away from the generation area the crest tends to become smaller than the trough and the maximum runup along the coast is given by the second or by the third wave an important feature is that the observed runup along the coast firstly grows with the distance from the generation area it reaches a maximum value at about two times the width of the landslide and then decreases an estimate of the celerity at which the waves propagate along the coast is given on the basis of gauge measurements it results that the crests propagate faster than the troughs and the wave period increases

landslide tsunamis propagating along a plane beach a forced two horizontal dimension analytical model is developed to investigate the distinguishing physical features of landslide induced tsunamis generated and propagating on a plane beach the analytical solution is employed to study the wave field at small times after the landslide motion starts at larger times the occurrence of transient edge waves travelling along the shoreline is demonstrated showing the differences with the transient waves propagating over a bottom of constant depth results are satisfactorily compared with available experimental data finally the validity of non forced numerical models is discussed

the propagation and diurnal cycles of deep convection in northern tropical africa the propagation and diurnal cycle of organized convection in northern tropical africa are examined using five years 1999 2003 of digital infrared imagery for may august reduced dimension techniques are used to document the properties of cold clouds proxies for deep convection and precipitation large scale environments are diagnosed from global analyses organized convection in africa consists of coherent sequences or episodes which span an average distance of about 1000 km and last about 25 h a substantial fraction of events exhibits systematic propagation at regional to continental scales while undergoing decay and regeneration episodes with 36 h duration and 1472 km span recur at a one per day interval most episodes have phase speed of 10 20 m s 1 which is faster than most african easterly waves convective episodes tend to initiate in the lee of high terrain consistent with thermal forcing from elevated heat sources average diurnal frequency maxima result from the superposition of local diurnal maximum with the delayed phase arrival of systems propagating from the east propagation occurs with moderate low to mid tropospheric shear which varies with the african easterly jet migration and west african monsoon phases frequent deep convection occurs with local shear maxima near high terrain for the peak monsoon period and for 10 w 10 e where easterly waves and convective systems are frequent 35 of cold cloud episodes occur east of the wave trough compared with about 24 to the west based on the coherent behaviour of organized propagating convection inferences may be made regarding the prediction of precipitation beyond one or two days copyright 2008 royal meteorological society

wavenumber frequency analysis of landslide generated tsunamis at a conical island part ii eof and modal analysis abstract in this paper the empirical orthogonal function eof method is applied to extract from the experimental data related to landslide tsunamis around the coast of a conical island the spatial modes that contribute to the wave field for each mode the wavenumber and the frequency are calculated by analyzing the shape along the coast and the time function the relevant modes are then compared with those obtained through numerical eigenanalysis of the long wave equation around the considered island it was possible to associate each eof mode with some eigenvectors and the corresponding eigenfrequencies both on the basis of the spatial shape the wavenumber calculated along the coast and the frequency results confirm that landslide generated waves propagate along the coast as trapped edge waves and the zero th order mode is the most important further of exploring the physics it is believed that this paper can be of use as some of the most relevant and straightforward techniques for modal identification are applied to the same problem and dataset

f k analysis of noress array and single station data to identify sources of near receiver and near source scattering abstract f k analyses of short period recordings of both u s and soviet underground nuclear explosions at the eskdalemuir eka scotland array indicate arrivals from a local source about 15 km due northwest of the array use of residual seismograms derived by subtracting the beamed record from each array channel confirmed the presence of the same scatterer the secondary seismic source appears to be short period surface waves due to the scattering of incident p waves at a nearby deep valley known as moffat water in agreement with key s 1967 earlier results similar analyses of the noress norway array data from u s and soviet nuclear shots also indicate secondary arrivals suggesting a local near surface scatterer about 25 30 km south west of the array in the region of lake mjosa thus short aperture array data can be useful in identifying and locating sources of near receiver scattering f k analyses of short period recordings of both explosion and earthquake sources at the high frequency noress array indicate secondary arrivals from a near receiver source about 25 30 km southwest of the array f k power difference plots obtained by subtracting after normalization the f k power versus slowness estimates for the initial p window from those for the later windows provided nearly identical results the secondary seismic source appears to be short period surface waves rg generated by the scattering of incident p waves in the region of lake mjosa 27 km sw of noress where there is about 1 km of relief from the bottom of the lake to the top of an adjacent hill

physical modeling of tsunamis generated by three dimensional deformable granular landslides 1 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

a modal decomposition method for the analysis of long waves amplification at coastal areas abstract this paper presents a model for the evaluation of long waves amplification at coastal areas based on a modal decomposition method it is able of modelling the growth and the decay of the natural modes of the area under investigation and their contribution to the total wave field the model is an improvement of that developed by bellotti et al 2012b that was able of calculating the frequencies and the shapes of the natural modes but not their amplification under the action of forcing waves three test cases are used for the validation and to show the capabilities of the model the first considers the long waves resonance into a long and narrow harbour bay over a constant water depth it is a case for which a high degree of wave trapping into the semi enclosed coastal area is induced by the specific shape of the coastline the second test deals with the propagation of a group of edge waves along a straight coast with a constant sloping bottom generated in proximity of the shoreline by a special wave maker the model in this case properly evaluates what are the edge waves modes that contribute to the total wave field the third case involves the interaction of a solitary wave with a conical island for which laboratory data are available in this test a low degree of trapping exists but it is interesting for the present aims as the propagation of the waves around the island is expected to occur under the form of wave modes partially trapped by the bathymetry i e edge waves excited by the transient wave arriving from offshore on the basis of the tests results it is shown what is the role of the more relevant natural modes in the formation of the total surface elevation

edge wave and non trapped modes of the 25 april 1992 cape mendocino tsunami the 25 april 1992 cape mendocino earthquake generated a tsunami characterized by both coastal trapped edge wave and non trapped tsunami modes that propagated north and south along the u s west coast both observed and synthetic time series at crescent city and north spit are consistent with the zero order edge wave mode solution for a semi infinite sloping beach depth profile wave amplitudes at crescent city were about twice that observed at north spit in spite of the fact that the source region was three times farther from crescent city than north spit the largest observed amplitude was due to an edge wave which arrived almost three hours after the initial onset of the tsunami since such waves are highly localized nearshore this suggests that the enhanced responsiveness at crescent city is at least partly due to local dynamic processes furthermore the substantially delayed arrival of this wave which was generated at the southern end of the cascadia subduction zone has significant implications for hazard mitigation efforts along the entire u s west coast specifically this study demonstrates that slow moving but very energetic edge wave modes could be generated by future large tsunamigenic earthquakes in the csz and that these might arrive unexpectedly at coastal communities several hours after the initial tsunami waves have subsided

laboratory experiments of tsunami runup on a circular island laboratory experiments of a 7 2 m diameter conical island were conducted to study three dimensional tsunami runup the 62 5 cm tall island had 1 on 4 side slopes and was positioned in the center of a 30 m wide by 25 m long flat bottom basin solitary waves with height to depth ratios ranging from 0 05 to 0 20 and source lengths ranging from 0 30 to 7 14 island diameters were tested in water depths of 32 and 42 cm twenty seven capacitance wave gages were used to measure surface wave elevations at incident and four radial transects on the island slope maximum vertical runup measurements were made at 20 locations around the perimeter of the island using rod and transit a new runup gage was located on the back or lee side of the island to record runup time series

shear instabilities in the longshore current a comparison of observation and theory abstract low frequency 0 01 hz oscillations in the surf zone longshore current with wavelengths too small 300 m to be surface gravity waves were observed during the 1986 superduck experiment at duck north carolina the observations suggest that these oscillations are dynamically linked to the mean longshore current in the surf zone leading bowen and holman to propose that the observed oscillations are manifestations of a shear instability in the longshore current in this paper field data from both the superduck experiment a barred beach and the l980 nsts experiment at leadbetter beach santa barbara california a plane beach are used to compare quantitatively the model of bowen and holman which is extended to include the effects of dissipation due to bottom friction with observation observed frequency cyclic wavenumber f k spectra constructed from alongshore arrays of velocity measurements made in about 1 5 2 m of water in the trough of the bar at superduck and in about 1 m at nsts

broadband f k analysis of array data to identify sources of local scattering f k analyses of short period recordings of both u s and soviet underground nuclear explosions at the eskdalemuir eka scotland array indicate arrivals from a local source about 15 km due northwest of the array use of residual seismograms derived by subtracting the beamed record from each array channel confirmed the presence of the same scatterer the secondary seismic source appears to be short period surface waves due to the scattering of incident p waves at a nearby deep valley known as moffat water in agreement with key s 1967 results similar analyses of the noress norway array data from u s and soviet nuclear shots also indicate secondary arrivals suggesting a local near surface scatterer about 25 30 km southwest of the array in the region of lake mjosa thus short aperture array data can be useful in identifying and locating sources of near receiver scattering

field observations of surf beat 1 progressive edge waves nineteen biaxial electromagnetic current meters have been used to determine the longshore and on offshore structure of currents at surf beat periods 1 4 min the sensors formed two linear arrays a long shore array within the surf zone and an on offshore array stretching from the shoreline to well beyond the breaker line analysis of the longshore current components yields a clear picture of progressive low mode edge waves with frequency wave number dispersion relations which are in remarkably good agreement with predictions some separation of edge wave modes is found with mode zero energy dominating in the frequency band 0 006 and 0 011 hz and mode one between 0 015 and 0 025 hz on offshore currents present a rather different picture which while not inconsistent with the longshore currents suggests that other sources of energy are also important to the on offshore currents these include standing edge waves probably formed by reflections at nearby scripps canyon and motions which are nonresonantly forced by incoming wave groups

tsunami trapping near circular islands trapping of long water waves that are induced by submarine earthquakes and that attack circular islands is studied by applying a theoretical model tinti andvannini 1994 that is based on the linear shallow water approximation the solution is computed as the superposition of the eigenmodes of the water basin the tsunami trapping is seen in terms of the capability of the source to excite the trapped eigenmodes of the basin the bottom depth dependence around the island is shown to be quite important in determining the trapping capability of the island a depth profile that is downwardly concave as the distance from the island coasts increases is substantially more efficient in amplifying the incoming waves and in trapping their energy than a profile exhibiting an upward concavity

lituya bay landslide impact generated mega tsunami 50th anniversary on july 10 1958 an earthquake mw 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

landslide tsunamis propagating around a conical island an analytical forced two horizontal dimension model is derived to investigate landslide tsunamis propagating around a conical island lying on a flat continental platform separation of variables and laplace transform are used to obtain the free surface elevation in the whole domain and the runup at the shoreline in terms of confluent heun functions the main properties of these functions and their asymptotic behaviour for large parameters are investigated expression of the transient leading wave travelling offshore is also derived the distinguishing physical features of landslide tsunamis propagating in a round geometry are then pointed out and compared with those of landslide tsunamis propagating along a straight coast analytical results satisfactorily agree with available experimental data

forecasting impulse waves generated by subaerial landslides 1 subaerial landslides falling into reservoirs or open seas generate impulsive water waves that are usually referred to as a class of tsunami waves it is important to study landslide generated waves occurring both in closed water basins where the waves interact with the shorelines and eventually the dam and in open seas where the generated waves can travel and deliver devastating damages hundreds of kilometers away in order to gain insight on subaerial landslide generated waves the italian national dam office recently funded an experimental and numerical research program geared to better understand and forecast tsunamis waves this paper introduces the experimental work which has been carried out in order to define empirical formulations able to forecast the principal features of the generated waves in a three dimensional water body as a function of the landslide movement wave types observed during the experiments are here characterized using a wavelet analysis approach new forecasting formulations named rid formulas are defined on the basis of the experimental study and tested using an artificial neural network model results are finally compared to those presented in past experimental studies

the landslides and tsunamis of the 30th of december 2002 in stromboli analysed through numerical simulations on the 30th of december 2002 two tsunamis were generated only 7 min apart in stromboli southern tyrrhenian sea italy they represented the peak of a volcanic crisis that started 2 days before with a large emission of lava flows from a lateral vent that opened some hundreds of meters below the summit craters both tsunamis were produced by landslides that detached from the sciara del fuoco this is a morphological scar and is the result of the last collapse of the northwestern flank of the volcanic edifice that occurred less than 5 ka b p the first tsunami was due to a submarine mass movement that started very close to the coastline and that involved about 20 106 m3 of material the second tsunami was engendered by a subaerial landslide that detached at about 500 m above sea level and that involved a volume estimated at 4 9 106 m3 the latter landslide can be seen as the retrogressive continuation of the first failure the tsunamis were not perceived as distinct events by most people they attacked all the coasts of stromboli within a few minutes and arrived at the neighbouring island of panarea 20 km ssw of stromboli in less than 5 min the tsunamis caused severe damage at stromboli

wavenumber frequency analysis of the landslide generated tsunamis at a conical island abstract in this paper we investigate the propagation of tsunamis generated by landslides around the coast of an island to understand the propagation and trapping mechanisms of the waves records of shoreline displacement have been processed using the wavenumber frequency analysis k f we identify the dispersion relation followed by the waves that propagate alongshore it appears that the 0th order edge wave mode is the only one relevant for shoreline run up furthermore it is shown that the edge wave dispersion relation is a quantitative tool to estimate the phase and group wave celerities a very good agreement is found when comparing the wave celerities as calculated from the experimental records against those predicted by the edge wave theory furthermore the analysis of the tsunami around the island has been carried out by means of the two dimensional k f using as input data a high space resolution dataset of free surface elevations it is found that other modes both trapped 1st order edge waves and non trapped free radiating waves occur during the propagation

numerical modelling of landslide tsunami propagation in a wide range of idealised water body geometries abstract large landslide tsunamis are caused by mass movements such as landslides or rock falls impacting into a water body research of these phenomena is essentially based on the two idealised water body geometries i wave flume 2d laterally confined wave propagation and ii wave basin 3d unconfined wave propagation the wave height in 2d and 3d differs by over one order of magnitude in the far field further the wave characteristics in intermediate geometries are currently not well understood this article focuses on numerical landslide tsunami propagation in the far field to quantify the effect of the water body geometry the hydrodynamic numerical model swash based on the non hydrostatic non linear shallow water equations was used to simulate approximate linear stokes cnoidal and solitary waves in 6 different idealised water body geometries this includes 2d 3d as well as intermediate geometries consisting of channels with diverging side walls the wavefront length was found to be an excellent parameter to correlate the wave decay along the slide axis in all these geometries in agreement with green s law and with diffraction theory in 3d semi theoretical equations to predict the wave magnitude of the idealised waves at any desired point of the water bodies are also presented further simulations of experimental landslide tsunami time series were performed in 2d to quantify the effect of frequency dispersion this process may be negligible for solitary and cnoidal like waves for initial landslide tsunami hazard assessment but becomes more important for stokes like waves in deeper water the findings herein significantly improve the reliability of initial landslide tsunami hazard assessment in water body geometries between 2d and 3d as demonstrated with the 2014 landslide tsunami event in lake askja

diurnal cycle of surface winds over the subtropical southeast pacific 1 the diurnal variability of surface winds over the se pacific is characterized with quikscat data for years 2000 2006 the twice daily satellite passes occur around 0600 and 1800 lt referred to as am and pm respectively the pm am wind difference maximizes in a region between 20 s and 30 s extending from the chilean coast up to 75 w this difference is mostly meridional along the coast with seasonal variation characterized by summertime weakening of the morning winds the observational analysis is supplemented with mesoscale model results for december 2003 they show that the coastal zonal flow increases between 0600 and 1200 local time lt but then decreases in the next 6 hours which explains the absence of an onshore component in the quikscat pm am difference additional model diagnostics show that in this region the diurnal cycle hodographs are more simple and larger above the marine boundary layer mbl than at the surface evaluation of the momentum and temperature budgets reveals the importance of the diurnal cycle of vertical velocity coupled with the thermal structure in controlling the diurnal cycle of the low level winds around 1300 lt coastal subsidence maximizes in a layer sloping from 1000 m at 36 s to 3000 m at 22 s inducing the development of a coastal trough at the surface during the night the passage of a high pressure perturbation reverses the surface meridional pressure gradient force inducing the decrease of the coastal meridional winds these results stress the important role played by the dynamics of the low troposphere above the mbl e g the heating of the andes cordillera to the east in controlling the wind diurnal cycles near the surface

resonance and impact of the 2009 samoa tsunami around tutuila american samoa 1 the 2009 samoa tsunami resulted in severe damage and inundation at tutuila american samoa the disparity of the impact and the varying accounts of the tsunami along the coast remain one of the most intriguing aspects of the event we utilize a dispersive wave model to reconstruct the tsunami from the earthquake source for understanding of the wave dynamics around tutuila after validation with water level measurements a fast fourier transform of the computed surface elevation reveals coupled resonance oscillations between 3 and 18 min period over the insular slope and shelf as well as the fringing reefs the resonance which focuses energy according to shelf and embayment configurations provides an explanation of the runup data and eyewitness accounts and identifies the coastal communities prone to tsunami hazards