long surface wave dynamics along a convex bottom 1 long linear wave transformation in a basin of varying depth is studied for a case of a convex bottom profile h x x4 3 this bottom geometry provides the nonreflecting wave propagation at least in the framework of the one dimensional shallow water equation in this case shoaling effects are very strong and wave reflection occurs in the immediate vicinity of the shoreline the existence of traveling wave solutions which propagate without reflection in this geometry is established through construction of a 1 1 transformation of the general 1 d wave equation to the analogous wave equation with constant coefficients the general solution of the cauchy problem consists of two traveling waves propagating in opposite directions and allows a detailed description of the wavefield vertical displacement and depth averaged flow it is found that generally a zone of weak current is formed between these two waves waves are reflected from the coastline so that their profile is inverted with respect to the calm water surface long wave runup on a beach with this profile is studied for the sine pulse korteweg de vries soliton and n wave it is shown that in certain cases the runup height along the convex profile is considerably larger than for beaches with a linear slope the analysis of wave reflection from the border of a shallow coastal area of constant depth and a section with the convex profile shows that a transmitted wave always has a sign variable shape results of the wave transformation above the convex beach and beaches following a general power law are compared this simplified model demonstrates the potential importance of the tsunami wave transformation along convex beaches

simulation of nonlinear wave run up with a high order boussinesq model abstract this paper considers the numerical simulation of nonlinear wave run up within a highly accurate boussinesq type model moving wet dry boundary algorithms based on so called extrapolating boundary techniques are utilized and a new variant of this approach is proposed in two horizontal dimensions as validation computed results involving the nonlinear run up of periodic as well as transient waves on a sloping beach are considered in a single horizontal dimension demonstrating excellent agreement with analytical solutions for both the free surface and horizontal velocity in two horizontal dimensions cases involving long wave resonance in a parabolic basin solitary wave evolution in a triangular channel and solitary wave run up on a circular conical island are considered in each case the computed results compare well against available analytical solutions or experimental measurements the ability to accurately simulate a moving wet dry boundary is of considerable practical importance within coastal engineering and the extension described in this work significantly improves the nearshore versatility of the present high order boussinesq approach

tsunami inundation modeling for western sumatra a long section of the sunda megathrust south of the great tsunamigenic earthquakes of 2004 and 2005 is well advanced in its seismic cycle and a plausible candidate for rupture in the next few decades our computations of tsunami propagation and inundation yield model flow depths and inundations consistent with sparse historical accounts for the last great earthquakes there in 1797 and 1833 numerical model results from plausible future ruptures produce flow depths of several meters and inundation up to several kilometers inland near the most populous coastal cities our models of historical and future tsunamis confirm a substantial exposure of coastal sumatran communities to tsunami surges potential losses could be as great as those that occurred in aceh in 2004

origin of the tertiary basaltic volcanism in the northern hessian depression volcanic activity started about 20 ma before present with quartz tholeiites qth had a climax with alkali olivine basalts aob 13 to 14 ma ago and ended 7 ma ago with nepheline basanites nb and olivine nephelinites on aob covers 73 of the volcanic area about 250 basalts and peridotite xenoliths were sampled for investigation an upper mantle layer ranging from about 90 to 60 km depth has been conditioned for a preferential alkali basalt production by advection of h2o co2 fluids containing si al ca k na p as major constituents beside numerous incompatible minor elements at the onset of the geodynamically triggered mantle conditioning locally restricted diapirism into shallow depth has caused formation of olivine tholeiite magmas oth at about 1 300 c by partial melting all of these oth primary melts intruded due to a favourable compressibility into granulites of the lower crust the rare qth basalts are their derivative magmas which have been slightly contaminated in the crust magmas of the subsequent alkali basaltic volcanism aob baob nb on mon formed by in situ partial melting at about 75 to 90 km depth after depression of the peridotite solidi by fluids to temperatures 1 200 c except many aob these magmas are primary melts as characterized by olivine melt distribution coefficients of mg fe2 kd 0 29 to 0 34 by ni concentrations 260 to 330 ppm and the occurrence of peridotite xenoliths rapid rise of gas charged melts due to saturation in co2 prevented separation of olivine etc and of xenoliths the sequence of magmas from oth to on or mon is formed from decreasing proportions of orthopyroxene opx and increasing contributions of clinopyroxene cpx and phlogopite ph at almost equal proportions of spinel sp incongruent melting of opx and cpx for oth aob nb and on is correlated with precipitation of olivine the average xenolith composition 73 ol 18 opx 7 cpx 1 1 sp and 1 3 0 5 ph was used to model the sources of the investigated melts by 9 incompatible elements and to calculate degrees of partial melting the occurrence of garnet cannot be reliably excluded by modelling on the basis of hree distribution coefficients the average xenolith composition was used for modelling because of its resemblance with worldwide sampled depleted mantle inclusions for avoiding to exhaust at least one mineral of the model mantle in the support of the norm composition of oth aob nb and mon magmas the degrees of partial melting cannot exceed 12 5 6 6 and 4 respectively mantle containing about 500 ppm k and the correlated incompatible elements like the average of 36 xenoliths allows to explain the formation of oth magmas aob nb and on melts require peridotite with slightly less than 1 500 ppm k 670 ppm p and proportions of the correlated elements lree sr ba zr rb cs ta th hf u which are higher than their abundance in primitive mantle rocks about 20 of the xenoliths have this composition metasomatism of fluids with these elements must have been an immediate precursor of the alkali basaltic volcanism otherwise the preservation of a local disequilibrium in 87sr 86sr ratios between cpx cores and total rock at upper mantle temperatures cannot be explained

the mineral chemistry of new titanates from the jagersfontein kimberlite south africa implications for metasomatism in the upper mantle new members of the crichtonite mineral series are described in which k ba ca and ree are in significant concentrations 5 wt oxides filling the a formula position in am21o38 these phases are chromium 16 wt cr2o3 titanates 58 wt tio2 enriched in zro2 5 wt and constitute a mineral repository for refractory and large ion lithophile elements in the upper mantle the mineral senes coexists with mg cr ilmenite nb cr rutile and ca cr nbzr armalcolite that have equally unusual chemistries kimberlitic crichtonites are depleted in the intermediate lanthanides but highly enriched in lree and hree with chondrite normalized abundances of 103 to 105 crichtonite armalcolite and nb cr rutile occupy a compositional range in tio2 contents bridging the gap between ilmenite and rutile two minerals having a widespread distribution in kimberlites and mantle derived nodule suites in common with other associations and based on similarities in mineral chemistry it is concluded that these minerals formed at p 20 30 kb 900 1100 c by reaction of peridotite with metasomatizing fluids kimberlitic crichtonite may be expressed as spinel cr ferropseudobrookite and armalcolite is equivalent to cr geikielite rutile in the system femg tio2 cr2o3 this system contains a number of cr ti compounds not found as minerals but it is proposed that the ubiquitous occurrence of ilmenite intergrowths in kimberlitic rutile results from decomposition of high pressure pbo2 type crystallographic shear structures the new minerals have exotic chemistries and the high k affinities broaden the scope for the origin of alkalic rocks the generation of highly potassic magmas in the upper mantle and suggest that alkali metasomatism may be pervasive

ree and selected trace elements in kimberlites from the kimberley area south africa abstract new data by ina methods on sc cs ree ta th and u in 11 kimberlites 1 phlogopite garnet harzburgite xenolith and 1 eclogite xenolith from the larger kimberley area are used to constrain models for kimberlite genesis kimberlite magmas are produced by melting of 61 clinopyroxene 60 olivine 22 phlogopite and 3 garnet of mantle rocks linked with precipitation of 46 orthopyroxene the accumulation of the incompatible elements la ce sr rb in kimberlites relative to garnet harzburgite has been modelled with the distribution coefficients of major mantle minerals to melts there is not much conformity between computed and observed abundances the degree of partial melting is estimated as 2 3 based upon kimberlite clinopyroxene balances complete melting of accessory mantle phases phlogopite phosphates carbonates etc and fractional melting of clinopyroxene eventually plus phlogopite of metasomatically altered garnet harzburgite can have contributed the major proportion of incompatible elements in kimberlites and melilite bearing olivine nephelinites the major fraction of hree in the latter rocks must have been supplied by mantle clinopyroxene and not by garnet this precludes the general discrimination between garnet peridotite and spinel peridotite equilibrated melts by means of the hree concentration of primary mantle magmas

geochemistry and geodynamic implications on the source of parana etendeka large igneous province evidenced by the 128 ma rosario 6 kimberlite southern brazil abstract the rosario 6 is a non diamondiferous hypabyssal kimberlite located above the rio de la plata craton and near the south eastern edge of the parana basin in southern brazil it is petrographically an inequigranular texture macrocrystal kimberlite fresh and the groundmass exhibits a microporphyritic texture and round megacrysts of olivine which are derived from disaggregated mantle xenoliths olivine is also present as macrocrysts microphenocrysts and in the groundmass together with phlogopite and apatite these microphenocrysts are immersed in a groundmass of olivine monticellite phlogopite catio3 perovskite apatite mg chromite and mg ulvospinel and melilite a mesostasis assemblage of phlogopite melilite soda melilite akermanite and calcium carbonate is segregated from the groundmass its geochemical signature is similar to those of transitional kimberlites of kaapvaal craton south africa and the u pb ages of 128 ma on perovskite reveal that rosario 6 kimberlite post dates the main pulse of volcanism in the parana etendeka large igneous province lip the high ti content of some minerals such as mg chromite mg ulvospinel phlogopite and melilite and the presence of perovskite suggest a ti rich source the petrographic geochemical and isotopic data indicate that the rosario 6 kimberlite source is a depleted mantle metasomatized by h2o rich fluids co2 rich and silicate melts derived from the recycling of an ancient subducted oceanic plate eclogite before the south atlantic opening although several authors indicate the influence of tristan da cunha plume for the generation of alkaline magmatism associated to the parana etendeka flood basalts our data demonstrates that tristan da cunha plume has no chemical contribution to the generation of rosario 6 kimberlite except by its thermal influence

empirical wave run up formula for wave storm surge and berm width abstract an empirical model to predict wave run up on beaches considering storm wave and surge conditions and berm widths dry beach has been derived through a synthetic data set generated from a one dimensional boussinesq wave model the new run up equation is expressed as a function of a new iribarren number composed of three regions the foreshore the berm or dry beach width and the dune the dissipative effect of the berm is included as a reduction factor expressed as a function of the berm width normalized by the offshore wavelength the equation is relatively simple but is shown to be applicable for a fairly wide variety of berm widths and storm wave conditions associated with extreme events such as hurricanes and it is shown to be an improvement over existing empirical run up models that do not consider the berm width explicitly in addition the new parameterization of the iribarren number considering the three regions and the berm width reduction factor are shown to improve other empirical models

rupture process of the 2004 sumatra andaman earthquake the 26 december 2004 sumatra andaman earthquake initiated slowly with small slip and a slow rupture speed for the first 40 to 60 seconds then the rupture expanded at a speed of about 2 5 kilometers per second toward the north northwest extending 1200 to 1300 kilometers along the andaman trough peak displacements reached 15 meters along a 600 kilometer segment of the plate boundary offshore of northwestern sumatra and the southern nicobar islands slip was less in the northern 400 to 500 kilometers of the aftershock zone and at least some slip in that region may have occurred on a time scale beyond the seismic band

run up of tsunamis and long waves in terms of surf similarity abstract in this paper we review and re examine the classical analytical solutions for run up of periodic long waves on an infinitely long slope as well as on a finite slope attached to a flat bottom both cases provide simple expressions for the maximum run up and the associated flow velocity in terms of the surf similarity parameter and the amplitude to depth ratio determined at some offshore location we use the analytical expressions to analyze the impact of tsunamis on beaches and relate the discussion to the recent indian ocean tsunami from december 26 2004 an important conclusion is that extreme run up combined with extreme flow velocities occurs for surf similarity parameters of the order 3 6 and for typical tsunami wave periods this requires relatively mild beach slopes next we compare the theoretical solutions to measured run up of breaking and non breaking irregular waves on steep impermeable slopes for the non breaking waves the theoretical curves turn out to be superior to state of the art empirical estimates finally we compare the theoretical solutions with numerical results obtained with a high order boussinesq type method and generally obtain an excellent agreement

wave characteristic and morphologic effects on the onshore hydrodynamic response of tsunamis abstract while the destruction caused by a tsunami can vary significantly owing to near and onshore controls we have only a limited quantitative understanding of how different local parameters influence the onshore response of tsunamis here a numerical model based on the non linear shallow water equations is first shown to agree well with analytical expressions developed for periodic long waves inundating over planar slopes more than 13 000 simulations are then conducted to examine the effects variations in the wave characteristics bed slopes and bottom roughness have on maximum tsunami run up and water velocity at the still water shoreline while deviations from periodic waves and planar slopes affect the onshore dynamics the details of these effects depend on a combination of factors in general the effects differ for breaking and non breaking waves and are related to the relative shift of the waves along the breaking non breaking wave continuum variations that shift waves toward increased breaking such as steeper wave fronts tend to increase the onshore impact of non breaking waves but decrease the impact of already breaking waves the onshore impact of a tsunami composed of multiple waves can be different from that of a single wave tsunami with the largest difference occurring on long shallow onshore topographies these results demonstrate that the onshore response of a tsunami is complex and that using analytical expressions derived from simplified conditions may not always be appropriate

full scale cfd simulation of tsunamis part 2 boundary layers and bed shear stresses abstract this paper presents results from numerical simulations of the propagation and run up of full scale tsunamis using a reynolds averaged navier stokes model with emphasis on the resulting boundary layers and bed shear stresses spatial distributions of the shields and rouse parameters during run up and draw down show that for the tsunamis considered with a sediment grain size corresponding to medium sand considerable sediment transport shields parameter o 10 o 100 can be expected during run up and that the sediment transport can be expected to be dominated by suspended load the results likewise show that the expected sediment transport during draw down will similarly be considerable and dominated by suspension the tsunami induced boundary layers are monitored in time and the observed boundary layer thickness ranges from spanning only a small fraction of the water depth to spanning the entire depth the velocity profiles beneath the tsunamis are shown to have good correspondence with a logarithmic profile within the boundary layer similarly the bed shear stresses beneath the tsunamis are investigated and a new and simple engineering model is developed for predicting the temporal variation of the bed shear stress based only on a free stream velocity signal the new engineering model is shown give better predictions for the bed shear stress than a standard manning approach and is likewise shown in the appendix to produce reasonable predictions for shorter wind scale waves it is finally also shown how the temporal evolution of the boundary layer thickness can be predicted based on the free stream velocity signal alone the results presented here are part 2 of a larger study where part 1 presents the model validation and detailed descriptions of the run up process

tsunami run up and draw down on a plane beach tsunami run up and draw down motions on a uniformly sloping beach are evaluated based on fully nonlinear shallow water wave theory the nonlinear equations of mass conservation and linear momentum are first transformed to a single linear hyperbolic equation to solve the problem with arbitrary initial conditions we apply the fourier bessel transform and inversion of the transform leads to the green function representation the solutions in the physical time and space domains are then obtained by numerical integration with this semi analytic solution technique several examples of tsunami run up and draw down motions are presented in particular detailed shoreline motion velocity field and inundation depth on the shore are closely examined it was found that the maximum flow velocity occurs at the moving shoreline and the maximum momentum flux occurs in the vicinity of the extreme draw down location the direction of both the maximum flow velocity and the maximum momentum flux depend on the initial waveform it is in the inshore direction when the initial waveform is predominantly depression and in the offshore direction when the initial waves have a dominant elevation characteristic

field data and satellite imagery of tsunami effects in banda aceh after the 26 december 2004 earthquake and tsunami field data on the extent of the inundation in banda aceh sumatra were combined with satellite imagery to quantify the tsunami effects flow depths along the shores of banda aceh exceeded 9 meters with inundation reaching 3 to 4 kilometers inland to the southwest at lhoknga flow depths were more than 15 meters at the shoreline and runup exceeded 25 meters erosion and subsidence moved the shoreline of banda aceh inland up to 1 5 kilometers and 65 square kilometers of land between banda aceh and lhoknga were flooded

tsunami source of the 2004 sumatra andaman earthquake inferred from tide gauge and satellite data tsunami source of the 2004 sumatra andaman earthquake was esti mated from a joint inversion of tsunami waveforms recorded on tide gauges and sea surface heights captured by satellite altimetry measurements the earthquake the largest in the past 40 years caused devastating tsunami damage to countries around the indian ocean but the tsunami source in particular its northern end was not well resolved although aftershocks and crustal deformation extended from off north western sumatra island through the nicobar islands to the andaman islands some seismic wave analyses indicated a shorter source length several hundred kilometers we used tsunami waveforms recorded at 12 tide gauge stations around the source and the sea surface heights measured by three satellites jason1 topex poseidon and envisat we numerically computed tsunami propagation using realistic bathym etry more than 66 000 depth points were digitized from nautical charts and combined with the etopo2 data inversion of satellite data indicates that the tsunami source extended to the andaman islands with a total length of 1 400 km but such a model produces much larger tsunami waveforms than observed at indian tide gauge stations inversion of tide gauge records and the joint inversion indicate that the tsunami source was about 900 km long the largest slip about 13 to 25 m was located off sumatra island and the second largest slip up to 7 m near the nicobar islands the slip distribution is similar for different rupture velocities and rise times with a slow velocity of 1 km sec and a rise time of 3 min yielding the largest variance reduction

intermediate depth earthquake faulting by dehydration embrittlement with negative volume change earthquakes are observed to occur in subduction zones to depths of approximately 680 km even though unassisted brittle failure is inhibited at depths greater than about 50 km owing to the high pressures and temperatures it is thought that such earthquakes particularly those at intermediate depths of 50 300 km may instead be triggered by embrittlement accompanying dehydration of hydrous minerals principally serpentine a problem with failure by serpentine dehydration is that the volume change accompanying dehydration becomes negative at pressures of 2 4 gpa 60 120 km depth above which brittle fracture mechanics predicts that the instability should be quenched here we show that dehydration of antigorite serpentinite under stress results in faults delineated by ultrafine grained solid reaction products formed during dehydration this phenomenon was observed under all conditions tested pressures of 1 6 gpa temperatures of 650 820 degrees c independent of the sign of the volume change of reaction although this result contradicts expectations from fracture mechanics it can be explained by separation of fluid from solid residue before and during faulting a hypothesis supported by our observations these observations confirm that dehydration embrittlement is a viable mechanism for nucleating earthquakes independent of depth as long as there are hydrous minerals breaking down under a differential stress

process based modeling of tsunami inundation and sediment transport 1 the infrequent and unpredictable nature of tsunamis precludes the use of field experiments to measure the hydrodynamic and sediment transport processes that occur instead these processes are often approximated from laboratory numerical and theoretical studies or inferred from observations of the resultant sediment deposits here delft3d a three dimensional numerical model is used to simulate the inundation and sediment transport of a tsunami similar in magnitude to the 26 december 2004 indian ocean tsunami over one measured and three idealized morphologies the model is first shown to match well the observations taken at kuala meurisi sumatra and then used to examine in detail the processes that occur during the tsunami the model predicts that at a given cross shore location the onshore flow accelerates rapidly to a maximum as the wavefront passes and then gradually decelerates before reversing direction and flowing offshore the onshore flow does not tend to zero everywhere at maximum inundation but instead flow reversal occurs near the shoreline even as the wavefront continues to inundate landward while some sediment is eroded by the passing wavefront the suspension of sandy sediment is dominated by the long duration high velocity backwash that occurs along the beach face and offshore of the shoreline some of the sediment suspended during backwash is advected shoreward by the subsequent wave creating large spatial gradients in the suspended sediment concentrations which may not be in equilibrium with the local hydrodynamics the inundation and transport of sediment during a tsunami can be affected by complexities in the morphological profile and interactions between multiple waves and many of the hydrodynamic and sediment transport processes predicted here are similar to analogous processes previously observed in the swash zone

the global reach of the 26 december 2004 sumatra tsunami numerical model simulations combined with tide gauge and satellite altimetry data reveal that wave amplitudes directionality and global propagation patterns of the 26 december 2004 sumatra tsunami were primarily determined by the orientation and intensity of the offshore seismic line source and subsequently by the trapping effect of mid ocean ridge topographic waveguides

the runup of solitary waves this is a study of the runup of solitary waves on plane beaches an approximate theory is presented for non breaking waves and an asymptotic result is derived for the maximum runup of solitary waves a series of laboratory experiments is described to support the theory it is shown that the linear theory predicts the maximum runup satisfactorily and that the nonlinear theory describes the climb of solitary waves equally well different runup regimes are found to exist for the runup of breaking and non breaking waves a breaking criterion is derived for determining whether a solitary wave will break as it climbs up a sloping beach and a different criterion is shown to apply for determining whether a wave will break during rundown these results are used to explain some of the existing empirical runup relationships

the influence of wave acceleration and volume on the swash flow driven by breaking waves of elevation abstract we study the swash flow driven by breaking waves of elevation using two sets of large scale experiments with a focus on understanding how wave properties control the flow evolution on the beach in the first set of experiments we test solitary waves and waveforms that have the same acceleration phase and wave height as the solitary waves but an elongated deceleration phase the results show that the run up and the flow in the immediate vicinity of the moving shoreline are similar showing that the shape of the wave acceleration phase controls these swash flow parameters in the second set of experiments we test waves generated by custom wavemaker trajectories previously reported in baldock et al 2019 in which the wave integrated volume flux wave height and wave period are varied the results show that waveforms with the same wave integrated volume flux produce nearly identical downrush flow despite having different wave heights and periods finally we present dimensionless plots of swash flow that illustrate the utility of separate scalings for uprush and downrush flow based on the wave acceleration and wave integrated volume flux respectively

analytical solutions for tsunami runup on a plane beach single waves n waves and transient waves in the literature it has so far been common practice to consider solitary waves and n waves composed of solitary waves as the appropriate model of tsunamis approaching the shoreline unfortunately this approach is based on a tie between the nonlinearity and the horizontal length scale or duration of the wave which is not realistic for geophysical tsunamis to resolve this problem we first derive analytical solutions to the nonlinear shallow water nsw equations for the runup rundown of single waves where the duration and the wave height can be specified separately the formulation is then extended to cover leading depression n waves composed of a superposition of positive and negative single waves as a result the temporal variations of the runup elevation the associated velocity and breaking criteria are specified in terms of polylogarithmic functions finally we consider incoming transient wavetrains generated by monopole and dipole disturbances in the deep ocean the evolution of these wavetrains while travelling a considerable distance over a constant depth is influenced by weak dispersion and is governed by the linear korteweg de vries kdv equation this process is described by a convolution integral involving the airy function the runup on the plane sloping beach is then determined by another convolution integral involving the incoming time series at the foot of the slope a good agreement with numerical model results is demonstrated

kinematics of breaking tsunami wavefronts a data set from large scale laboratory experiments abstract this paper provides an overview of a new large scale laboratory data set on the kinematics of breaking tsunami wavefronts the aim of the experiments was to provide an open access data set for model testing calibration and verification with particular emphasis on fluid kinematics in the wave breaking and run up swash zones the experiments were performed over a composite slope in the tsunami wave basin at the o h hinsdale wave research laboratory at oregon state university data for ten different wave conditions were collected including non breaking and breaking waves and both shore breaks and fully developed long bores surface elevation and fluid kinematics were measured with a closely spaced array of surface piercing wave gauges non contact ultrasonic wave gauges and four 3 d side looking acoustic doppler velocimeters the array was traversed from the nearshore depth 0 2 m to the middle and upper run up zone providing kinematic data at 30 cross shore locations video was also recorded from 4 cameras covering the propagation breaking and run up zones surface elevation flow velocities and the wave maker displacement were also recorded to provide offshore boundary conditions the experiments include conditions with wave heights up to 0 55 m notional wave periods up to 20 s and run up lengths of up to 15 2 m on a 1 30 slope in terms of the slope in the shoaling and breaker zones the data correspond to iribarren numbers in the range of 0 26 5 6 raw calibrated and processed data are stored with open access within the osu tsunami wave basin experiment notebook which provides full access to all the wave maker control signals data instrument coordinates and processing and plotting software this paper serves as an introduction to the data set demonstrates data quality and provides an initial analysis of some key parameters that govern the impact of tsunami events including run up versus offshore wave conditions and nearshore bore height the maximum inundation depths at the original shoreline position and the time to maximum inundation depth and flow reversal examples of temporal and convective accelerations and turbulent flow components are also presented to illustrate further details of the kinematics

a flying start then a slow slip the human tragedy caused by the sumatra andaman earthquake moment magnitude 9 3 on 26 december 2004 and its companion nias earthquake moment magnitude 8 7 on 28 march 2005 is difficult to comprehend these earthquakes the largest in 40 years have also left seismologists searching for the words and tools to describe the enormity of the geological processes involved four papers in this issue discuss aspects of a rupture process of surprising complexity the first such event to test the sensitivity and range of many new technologies a surprising feature of the earthquake is that after the initial rapid rupture subsequent slip of the plate interface occurred with decreasing speed toward the north