the kinematics of movements along the insubric line and the emplacement of the ivrea zone schmid sm zingg a and handy m 1987 the kinematics of movements along the insubric line and the emplacement of the ivrea zone in h j zwart m martens i van der molen c w passchier c spiers and r l m vissers editors tectonic and structural processes on a macro meso and micro scale tecta a hys 135 47 66 the insubric line west of locamo is characterized by a 1 km thick greenschist facies mylonite belt east of locamo these mylonites are overprinted by a discrete brittle fault the mylonites are derived from basement units of the central alps sesia zone and the southern alps ivrea zone as well as from the permo mesozoic cover of the southern alps canavese sense of shear criteria indicate that the mylonites accomm ated backt s g followed by dextral strike slip motion mylonitization during backtbrusting was synchronous with backfolding of the central alpine nappes under higher metamorphic conditions a horizontal temperature gradient resulted from the rapid juxtaposition of the warm central alpine block against the cold southern alpine block mylonites formed during the later dextral strike slip event are related to large transcurrent displacements in the central alps deduced from regional kinematic considerations thus both mylo t ation events are contempor eous with deformation to the north and south of the insubric line insubric phase extensively modifying the pre insubric crustal configuration of the alps the insubric phase post dates the bergell intrusion 30 m y the emplacement of the geophysical ivrea body is a combined effect of vertical uplift due to e w directed crustal thinning during the early jurassic and underplating by continental crust associated with late cretaceous compression a deep crustal normal fault pogallo line subsequently rotated during tertiary alpine orogenesis separates deeper parts of the southern alpine crust ivrea zone from intermediate crustal levels strona ceneri zone the rigid ivrea body localir ed large strains within the insubric mylonite belt and is responsible for the present curvature of the insubric line in uetion

longitudinal development of low latitude ionospheric irregularities during the geomagnetic storms of july 2004 1 during the period 22 28 july 2004 three geomagnetic storms occurred due to a sequence of coronal mass ejections in this paper we present and discuss the ionospheric observations from a set of in situ satellites and ground based gps total electron content and scintillation receivers a vhf radar and two chains of ionosondes 300 e and 120 e respectively that provide the evolutionary characteristics of equatorial and low latitude ionospheric irregularities versus longitude during these storm periods it is found that the irregularities occurred over a wide longitudinal range extending from around 300 e to 120 e on storm days 25 and 27 july 2004 on 25 july plasma bubbles pbs began premidnight in america and postmidnight in southeast asia on 27 july the occurrence of irregularities followed the sunset terminator and was observed sequentially after sunset from american to southeast asian longitudes past studies have reported that storm time low latitude ionospheric irregularities are mostly confined to a narrower longitude range 90 after sunset hours and are associated with the prompt penetration of eastward electric fields ppefs into low latitudes in june solstice months the occurrence of range type spread f or pbs is very low in southeast asian and south american sectors in contrast the present results indicate that geomagnetic storms triggered the wide longitudinal development of pbs in the american sector this was probably due to the effects of ppefs on both storm days however in the southeast asian sector the pbs on the 2 days probably arose from disturbance dynamo electric field ddef ppef and gravity wave seeding effects this study further shows that under complex storm conditions besides the long duration or multiple penetrations the combined effects of ppefs and ddefs could result in a wide longitude extent of ionospheric irregularities at times

mechanics of fold and thrust belts and accretionary wedges cohesive coulomb theory a critically tapered fold and thrust belt or submarine accretionary wedge is one that is on the verge of coulomb failure everywhere including its base where frictional sliding along a decollement is assumed to be occurring cohesion within a wedge can add significantly to the overall strength near the toe the effect of this is to decrease the near toe taper leading to a critical topographic profile that is concave upward if the decollement is planar we obtain an approximate self consistent solution for the state of stress within a thin skinned cohesive critical coulomb wedge and determine the relationship between the wedge taper and its strength and basal friction the theory is then applied to the presently deforming fold and thrust belt of western taiwan fitting of theoretical critical wedge shapes to topographic profiles and measurements of the step up angles of thrust faults from the basal decollement are used to constrain the taiwan wedge strength parameters an attractive assertion fully consistent with all the observations is that the mechanics of fold and thrust belts and accretionary wedges is governed by normal frictional and fracture strengths of rocks measured in the laboratory in particular if byerlee s law b 0 85 is adopted as the coefficient of sliding friction on the base we find a coefficient of internal friction 0 9 1 0 in the wedge and a wedge cohesion so 5 20 mpa other solutions having strengths and ambient stresses up to 4 times lower than this can also however satisfy the data

empirical models of storm time equatorial zonal electric fields ionospheric plasma drifts often show highly complex and variable signatures during geomagnetically active periods due to the effects of different disturbance processes we describe initially a methodology for the study of storm time dependent ionospheric electric fields we present empirical models of equatorial disturbance zonal electric fields obtained using extensive f region vertical plasma drift measurements from the jicamarca observatory and auroral electrojet indices these models determine the plasma drift perturbations due to the combined effects of short lived prompt penetration and longer lasting disturbance dynamo electric fields we show that the prompt penetration drifts obtained from a high time resolution empirical model are in excellent agreement with results from the rice convection model for comparable changes in the polar cap potential drop we also present several case studies comparing observations with results obtained by adding model disturbance drifts and season and solar cycle dependent average quiet time drift patterns when the disturbance drifts are largely due to changes in magnetospheric convection and to disturbance dynamo effects the measured and modeled drift velocities are generally in good agreement however our results indicate that the equatorial disturbance electric field pattern can be strongly affected by variations in the shielding efficiency and in the high latitude potential and energy deposition patterns which are not accounted for in the model these case studies and earlier results also suggest the possible importance of additional sources of plasmaspheric disturbance electric fields

results of nfp 20 seismic reflection profiling along the alpine section of the european geotraverse egt summary recent deep crustal seismic reflection profiling across the central alps of eastern and southern switzerland has provided a detailed image of this continental collision zone as part of the swiss national science project nfp 20 a series of reflection profiles was recorded during two phases along n s transects crossing the alpine edifice the eastern and southern profiles coincide with the alpine segment of the european geotraverse egt and in part with the earlier swiss geotraverse these data together with other geophysical and extensive geologic information form a unique and comprehensive volume of crustal information for this region of the alps on a larger scale the new reflection data also add to a growing set of profiles crossing the alpine fold belt which includes an additional traverse carried out by nfp 20 across the western swiss alps and the ecors crop profile across the western alps the initial results of the reflection data across the central alps outline a crustal framework involving northward indentation of the adriatic hinterland into the subducting european foreland this occurs beneath the collapsed oceanic basins of the penninic allochthon which is defined by its highly reflective crystalline nappes the present crustal thickness within the alpine collision zone has doubled to about 60 km by both vertical and horizontal displacements along an inferred complex detachment system controlled by the adriatic wedge the south plunging european foreland implies that portions of the thickened crust have been subducted into the upper mantle this general framework of flake tectonics is laterally consistent with the ecors crop results from the western alps however the western alps show a higher degree of crustal imbrication which may be related to the presence of the rigid ivrea body and an overall greater amount of crustal shortening compared to the central alps

some comments on two layer extensional models for the evolution of sedimentary basins simple extensional models that involve listric faulting in the brittle upper crust and plastic flow in the lower lithosphere have been shown to account for the subsidence history of various continental sedimentary basins and continental shelves in this paper we present structural evidence that extension in the continental lithosphere during rifting is not uniform we review evidence that the rifting process in major intracratonic rift basins is spasmodic rather than continuous that extension and subsidence within the rift during a tectonic phase is generally accompanied by uplift and erosion of the rift flanks that subcrustal heat input during rifting occurs over an area much broader than the rift proper and that there may be broad regional uplift before and or during rifting to explain the uplift of the flanks during rifting and their postrift subsidence we invoke two mechanisms subcrustal thinning by extension below the flanks and tilted major normal faults in the crust between graben and flanks the uplift and erosion of the flanks due to tilted faults probably do not significantly affect estimates of extension from subsidence analysis but uplift due to both sources can in certain cases be incorrectly attributed to regional uplift or doming we present a simplified analysis of the two layer extensional model for the elementary case in which extension is instantaneous and the crust is thinned by a different amount from the subcrustal lithosphere we provide a simple graphical method of data analysis to obtain the parameters that describe thinning of the crust and lithosphere during extension from the subsidence history application of this method to the central part of the pattani trough in the intracratonic gulf of thailand shows that extension and thinning of the lithosphere of a factor of 2 since late eocene can account for much of the subsidence history and the present day heat flow our analysis suggests that thinning of the crust in this area is 20 greater than thinning of the whole lithosphere assuming that none of the lithosphere is removed from the region of extension during rifting we show by simple geometric examples that a process of nonuniform extension implies that much greater thicknesses of sediment can be deposited in the center of a young basin than in the case of uniform extension of both crust and subcrustal lithosphere such an extensional process produces significant uplift of the flanks of the rift and as a result of erosion of the uplifted areas the effective cross sectional area of the basin can be increased by as much as 10 20 depending on the rate of erosion compared to the area that would have been created by a process of uniform extension finally we show that it may ultimately be possible to compute erosion rates from seismic cross sections of basins

importance of hercynian tectonics within the framework of the southern alps abstract the hercynian remnants present within the alpidic structural zones of the southern alps are reviewed the pattern of hercynian metamorphism is zonal from granulites in the western area to anchimetamorphic facies in the eastern one in the folded zone at the eastern margin a severe hercynian folding phase took place during the westphalian thrust sheets comprising sequences of different facies ranging in age from caradocian to early westphalian are sutured by late westphalian molasse deposits the assumption that the southern alps and the external dinarides remained outside the hercynian folding front is contradicted by field evidence

reply to comment by f masci and j n thomas on temporal and spatial precursors in ionospheric total electron content of the 16 october 1999 mw7 1 hector mine earthquake

common origin of positive ionospheric storms at middle latitudes and the geomagnetic activity effect at low latitudes anomalous increases of the ionization density at middle latitudes positive ionospheric storms and anomalous increases of the neutral gas density at low latitudes the geomagnetic activity effect are prominent features of upper atmospheric storms the present study investigates the idea that both phenomena are caused by traveling atmospheric disturbances tads according to theory such tads are generated during magnetic substorm activity and propagate with high velocity from polar to equatorial latitudes to examine the above hypothesis magnetic ionospheric and neutral atmospheric data are compared for five different disturbance events these case studies demonstrate that 1 there is a good temporal correlation between magnetic substorm activity at high latitudes daytime positive ionospheric storms at middle latitudes and the geomagnetic activity effect at low latitudes 2 the initial phase of positive ionospheric storms propagates with high velocity toward lower latitudes 3 this velocity is roughly consistent with the time lag of the geomagnetic activity effect at low latitudes 4 the ionospheric disturbance is a conjugate phenomenon of global extent and 5 it cannot be explained as an electric field effect in summary our data are fully consistent with the idea that tads are responsible for both positive ionospheric storms at middle latitudes and the geomagnetic activity effect at low latitudes

andean age structure of eastern cordillera province of la paz bolivia a moho root beneath the bolivian andes 40 km deep is consistent with 230 km of overlap of neogene age on a single trenchward dipping transcrustal thrust fault with 10 of finite ramp cutoff main andean thrust mat only 10 of the andean crustal volume is ascribable to magmatic addition the mat is located within south american crust of full thickness it intersects the basement top 450 km inland from the neogene crustal margin it is not a collision suture as shown by persistent pre neogene facies continuity thrusting is not accompanied by terrane accretion the present bilaterally symmetrical thrust belt responds to elastic line loading and to coulomb rheology in the hanging wall of the mat a deep high stress wedge base builds a steep critical slope in the footwall the foredeep response is fast subcritical growth by progradation and blind thrusting on a low stress decollement interaction is maintained by out of sequence renewal of movement on the mat

a case study of ionospheric storm effects during long lasting southward imf bz driven geomagnetic storm multiple instrumental observations including gps total electron content tec fof2 and hmf2 from ionosondes vertical ion drift measurements from communication navigation outage forecasting system magnetometer data and far ultraviolet airglow measured by thermosphere ionosphere mesosphere energetics and dynamics global ultraviolet imager timed guvi are used to investigate the profound ionospheric disturbances at midlatitude and low latitude during the 14 17 july 2012 geomagnetic storm event which was featured by prolonged southward interplanetary geomagnetic field component for about 30 h below 10 nt in the east asian australian sector latitudinal profile of tec variations in the main phase were characterized by three bands of increments and separated by weak depressions in the equatorial ionospheric anomaly eia crest regions which were caused by the combined effects of disturbance dynamo electric fields ddef and equatorward neutral winds in the recovery phase strong inhibition of eia occurred and the summer crest of eia disappeared on 16 july due to the combined effects of intrusion of neutral composition disturbance zone as shown by the timed guvi o n2 measurements and long lasting daytime westward ddef inferred from the equatorial electrojet observations the transit time of ddef over the dip equator from westward to eastward is around 2200 lt in the american longitude the salient ionospheric disturbances in the summer hemisphere were characterized by daytime periodical intrusion of negative phase for three consecutive days in the recovery phase preceded by storm enhanced density plume in the initial phase in addition multiple short lived prompt penetration electric fields appeared during stable southward interplanetary magnetic field imf bz in the recovery phase and were responsible for enhanced the eia and equatorial ionospheric uplift around sunset

characterizing the 10 november 2004 storm time middle latitude plasma bubble event in southeast asia using multi instrument observations 1 the development and dynamics of ionospheric plasma bubble pb irregularity during the super storm of 7 11 november 2004 are investigated using the data from a multi instrument network operated in southeast asia analysis of fluctuations in global positioning system total electron content gps tec ionosonde gps scintillation and in situ satellite density data indicates a series of intense pb associated irregularities at equatorial low and middle latitudes in the japanese longitude on 10 november however in the chinese sector the scintillations and pb irregularities are confined within the range of 20 50 n in geographic latitude and 110 125 e in geographic longitude the absence of equatorial pb irregularities in this sector shows a major difference from that in the close by longitude japanese sector in the southern hemisphere australian sector the irregularities occurrence is present as a symmetrical distribution at conjugate latitudes combined analysis of the data from osan and wuhan ionosondes illustrates that the middle latitude spread f irregularities initially develop at the lower part of the f region and then distribute in the whole f region this initiation of spread f at lower altitudes indicates that the middle latitude pb associated irregularities are locally generated these results together with the irregularities occurrence sequence from higher to lower latitudes and the onset time delay of several hours implies that the presence of pb associated irregularities within a latitude range of 20 50 n in the chinese sector cannot be attributed to the effects of prompt penetration electric fields ppefs although the equatorial pbs in the close by longitude are seen to be associated with ppefs the possible mechanism is the f region plasma instabilities triggered by wave structures which act as an external driving force and seed active plasma dynamics and instability growth at middle latitude

ionosphere disturbances observed throughout southeast asia of the superstorm of 20 22 november 2003 1 ionospheric disturbances in the southeast asian region during the super magnetic storm of 20 22 november 2003 were investigated through an ionosonde chain and a gps network assisted by the space borne instruments at early stage of the storm in the postsunset sector large enhancements in the critical frequency of f2 layer and total electron content were observed at northern crest region of the equatorial ionization anomaly eia which might be produced by both the storm meridional wind superimposed with traveling atmospheric disturbances and prompt penetration electric field ppe during the main phase of the storm when interplanetary magnetic field started a 12 h southward turning equatorial ionosphere was elevated to a very high level which should be most probably caused by a long duration ppe event meanwhile at mid low latitudes ionosphere witnessed an initial simultaneous decrease then followed by drastic increases which is very different from the past observations in this region reddy and nishida 1992 combined analysis of the data from the ionosonde and other space based measurement shows that for the present case the penetration efficiency of the interplanetary electric field ief to the equatorial ionosphere was larger at night than in the daytime which agrees with the results of fejer et al 2007 showing the ratios of ppe and ief changes were highly variable with the local time during the recovery phase eia was severely inhibited owing to a wind convergence and possibly because of the westward disturbance dynamo electric field

field survey of the 1994 mindoro island philippines tsunami this is a report of the field survey of the november 15 1994 mindoro island philippines tsunami generated by an earthquake m 7 0 with a strike slip motion we will report runup heights from 54 locations on luzon mindoro and other smaller islands in the cape verde passage between mindoro and luzon most of the damage was concentrated along the northern coast of mindoro runup height distribution ranged 3 4 m at the most severely damaged areas and 2 4 in neighboring areas the tsunami affected area was limited to within 10 km of the epicenter the largest recorded runup value of 7 3 m was measured on the southwestern coast of baco island while a runup of 6 1 m was detected on its northern coastline the earthquake and tsunami killed 62 people injured 248 and destroyed 800 houses as observed in other recent tsunami disasters most of the casualties were children nearly all eyewitnesses interviewed described the first wave as a leading depression wave eyewitnesses reported that the main direction of tsunami propagation was sw in subaang bay se in wawa and calapan ne on baco island and n on verde island suggesting that the tsunami source area was in the southern pass of verde island and that the wave propagated rapidly in all directions the fault plane extended offshore to the n of mindoro island with its rupture originating s of verde island and propagating almost directly south to the inland of mindoro thereby accounting for the relatively limited damage area observed on the n of mindoro

gravity anomalies and flexure of the lithosphere at mountain ranges the bouguer gravity anomaly over the himalayan alpine and appalachian mountains is characterized by a generally asymmetric gravity low which spans the mountains and associated foreland basins the minimum of the gravity low is generally systematically displaced from the region of greatest topographic relief and shows no obvious relationship to surface geology in addition the alps and appalachians are associated with a generally symmetric gravity high that is unrelated to the topographic relief together the gravity low and high form a characteristic positive negative anomaly couple the steep gravity gradient between the positive and negative couple correlates with the insubric line and its equivalents in the alps and the brevard zone in the southern appalachians this gravity anomaly couple is interpreted as evidence for flexure of the continental lithosphere by subsurface buried and surface topographic loading the magnitude of the subsurface load is estimated from the integrated excess mass represented by the positive anomaly and the magnitude of the surface load from the topography by combining these loads the flexure of the lithosphere and the associated bouguer gravity anomaly are calculated for different assumed values of the elastic thickness te of continental lithosphere the best fitting value of te for the himalayas is 80 100 km for the alps 25 50 km and for the appalachians 80 130 km the model calculations suggest that the main contribution to the gravity couple in the alps and appalachians arises not from surface loads such as thrust sheets and nappes but from subsurface loads however in the case of the himalayas the topography appears to be a sufficient load to explain the observed asymmetric gravity low when subsurface loads do exist therefore we would not expect a close correlation between mountain topographic relief and depth to the m discontinuity as required by classical models of isostasy rather the m discontinuity is expected to relate to the center of mass of all the loads acting on the lithosphere the surface and subsurface loads inferred from the gravity anomaly play a major role in the development of mountains and foreland basins the emplacement of large subsurface loads represents the primary event in the alps and appalachians while in the himalayas the emplacement of the surface load is the primary event the emplacement of the subsurface load probably marks the initiation of foreland basin development the regional characteristics of the basin are controlled by the primary load while local variations are controlled by the secondary thrust sheet loads subsequent movement of either load will produce migration of the basin depocenter the origin of the subsurface load is not clear but its association with the insubric line in the alps and the brevard zone in the appalachians suggests that it may be related to the obduction of crustal blocks flakes onto the underlying plate during continental collision or possibly to the preloaded crustal structure of the underlying plate

the propagation of traveling atmospheric disturbances observed during the april 6 7 2000 ionospheric storm 1 the great magnetic storm of april 6 7 2000 generated ionospheric disturbances in the west pacific region two ionosondes at wuhan 30 6degreesn 114 4degreese and chung li 24 9degreesn 121 e observed the ionosphere during this period the variations of the ionospheric parameters nmf 2 plasma density of the f peak hmf 2 height of the f peak and h f minimum virtual height of the f layer show that a traveling atmospheric disturbance tad affects the ionosphere at middle and low latitudes in this region the propagation velocities deduced from the time delay of hmf 2 and h f recorded at the two stations are about 655 and 164 m s respectively furthermore a method of deriving the vertical phase and group velocities is applied to the sequences of virtual heights at fixed sounding frequencies the vertical and associated meridional velocities demonstrate that the upward motions of the ionospheric plasma are caused by a tad

the 1994 shikotan earthquake tsunamis the 1994 shikotan earthquake was one of the greatest earthquakes in recent years with a magnitude of m s 8 0 a tsunami survey was conducted by russian and u s geophysicists from october 16 30 1994 less than two weeks after the earthquake the survey results and a numerical hindcast simulation are reported tsunami focusing effect at locations supposedly sheltered by the island chain is discussed based on the obtained data tsunamis which attacked shikotan island are characterized as long waves the order of 10 20 min wave period with a positive leading wave possible consequences of the positive leading wave form are discussed in relation to the observed minimal destruction of beach vegetation and relatively small transport of marine sediment onto the shore the high quality tide gage record in malokurilskaya bay indicates the occurrence of a 53 cm subsidence at the site

field survey of the east java earthquake and tsunami of june 3 1994 a field survey of the june 3 1994 east java earthquake tsunami was conducted within three weeks and the distributions of the seismic intensities tsunami heights and human and house damages were surveyed the seismic intensities on the south coasts of java and bali islands were small for an earthquake with magnitude m 7 6 the earthquake caused no land damage about 40 minutes after the main shock a huge tsunami attacked the coasts several villages in east java province were damaged severely and 223 persons perished at pancer village about 70 percent of the houses were swept away and 121 persons were killed by the tsunami the relationship between tsunami heights and distances from the source shows that the hatori s tsunami magnitude was m 3 which seems to be larger for the earthquake magnitude but we should not consider this an extraordinary event because it was pointed out by hatori 1994 that the magnitudes of tsunamis in the indonesia philippine region generally exceed 1 2 grade larger than those of other regions

storm time dependence of equatorial disturbance dynamo zonal electric fields we use jicamarca radar observations of f region vertical plasma drifts and auroral electrojet indices during 1968 1988 to study the characteristics and temporal evolution of equatorial disturbance dynamo zonal electric fields these electric fields result from the dynamo action of storm time winds and or thermospheric composition changes driven by enhanced energy deposition into the high latitude ionosphere during geomagnetically active conditions the equatorial vertical drift perturbations last for periods of up to 30 hours after large increases in the high latitude currents on the average this process can be described by two basic components with time delays of about 1 12 hours and 22 28 hours between the high latitude current enhancements and the equatorial velocity perturbations our data indicate strong coupling between dynamo processes with different timescales the short term disturbance dynamo drives upward equatorial drifts eastward electric fields at night with largest amplitudes near sunrise and small downward drifts during the day these perturbation drifts are in good agreement with results from the blanc richmond disturbance dynamo theory the dynamo process with time delays of about a day drives upward drift velocities at night with largest values near midnight and downward drifts in the sunrise noon sector in this case the amplitudes of the disturbance drifts maximize during geomagnetically quiet times preceded by strongly disturbed conditions we also present results of a new equatorial storm time dependent empirical model which illustrate the characteristics of the vertical disturbance dynamo drifts

tsunami simulations of the sulawesi m w 7 5 event comparison of seismic sources issued from a tsunami warning context versus post event finite source the 28 september 2018 sulawesi earthquake generated a much larger tsunami than expected from its mw 7 5 magnitude and from its dominant strike slip mechanism within a few minutes after the earthquake the tsunami devastated the seafront of palu bay destroying houses and infrastructures over a few hundred meters coastal subsidence and slumping at various locations around the bay were also observed there is debate in the scientific community as to whether submarine landslides and shore collapses contributed to the generation of strong and destructive waves locally the objective of this study is threefold first to determine whether standard seismic inversions could predict the source in the context of tsunami early warning second to define a new seismic source built from optical image correlation and based on the geological and tectonic context third to assess whether the earthquake alone is able to generate up to 9 m wave heights at the coast numerical simulations of the tsunami propagation are performed for different seismic dislocation sources nonlinear shallow water equations are solved by a finite difference method in grids with 200 m and 10 m resolutions the early cmt focal solutions calculated by seismological institutes show dominant strike slip mechanisms with a homogenous slip distribution these sources produce maximum tsunami heights of 40 cm on the coast of palu city two heterogeneous sources are tested and compared the usgs finite fault model calculated from seismic inversion and a new hybrid source inferred from different techniques the latter is based on a segmented fault in agreement with the geological context and built from both from seismic parameters of a cmt solution and the observed horizontal ground displacements this source produces water wave heights of 4 to 5 m in the palu bay the observed inundation heights and distances are reproduced satisfactorily by the model at pantoloan and at the southwestern tip of palu bay however the hybrid source is unable to reproduce the largest 8 to 12 m water heights as reported from field surveys thus even though this hybrid source produces most of the reported tsunami energy we cannot exclude that the numerous coastal collapses observed in palu bay contributed to increase the local tsunami run up

high speed stream impacts on the equatorial ionization anomaly region during the deep solar minimum year 2008 1 to demonstrate high speed stream effects during the recent deep solar minimum year 2008 we have analyzed manually scaledfof2 and hmf2 at jicamarca and total electron content tec in the equatorial ionization anomaly eia region over the america longitudinal sector our results reveal that a prominent 9 day oscillation appears in the hmf2 and fof2 at the dip equator the 9 day oscillation amplitudes of fof2are not always positively correlated with tec in the equatorial ionosphere and they show nonlinear dependence on the intensity of geomagnetic disturbances with the outputs of fejer and scherliess s 1997 empirical model we found that this periodicity is also present in equatorial vertical drifts caused by disturbance dynamoelectric field ddef but absent in the drifts due to prompt penetration electric field ppef ddef effects on the equatorial periodic variations alone are not sufficient to explain the observed phenomena other mechanisms such as thermal expansion contraction and neutral composition changes are also the plausible causes of the periodic oscillation in the equatorial ionosphere further the complicated patterns appear in the 9 day band pass filtered tec perturbations in the eia region and they are quite different from the patterns of global coherent thermospheric oscillations triggered by high speed streams we also found that the latitudinal variations of band passed filtered tec present different behaviors involving tilt latitudinal configuration antiphased correlation between the crests and trough and south north asymmetry which vary as a function of season local time or even from event to event

characteristics of the large scale traveling atmospheric disturbances during geomagnetically quiet and disturbed periods simulated by a whole atmosphere general circulation model 1 we have investigated characteristics of the large scale traveling atmospheric disturbances ls tads generated during geomagnetically quiet and disturbed periods using a whole atmosphere general circulation model gcm the gcm simulations show that various tads appear in association with passages of regions with large temperature gradients near the solar terminator midnight temperature anomaly and auroral oval which move with the earth s rotation these tads which are superimposed on each other appear even when a geomagnetically quiet period the tads generated during a geomagnetically quiet period show structures extending in the longitudinal direction at high latitude and in the latitudinal direction at mid and low latitude these structures disappear after their short range propagations the tads generated during a geomagnetically disturbed period show structures extending widely in the longitudinal direction and propagate from high to low latitude these simulation results suggest the different generation mechanisms and features between the tads generated during geomagnetically quiet and disturbed periods

modeling the ionospheric response to traveling atmospheric disturbances anomalous increases of the ionization density at middle latitudes positive ionospheric storms are often a prominent feature of upper atmospheric storms one of their possible causes are traveling atmospheric disturbances tads which propagate from polar to equatorial latitudes carrying along equatorward directed meridional winds at middle latitudes these winds cause an increase in the height of the f2 layer which in turn will lead to an enhancement of the ionization density using a simple description of a tad and an ionospheric model we are able to reproduce the basic properties of such perturbations we also attempt to simulate an actually observed storm period rough agreement is obtained when the wind speed is derived from the height of the f2 layer peak a more detailed simulation of the initial phase of the storm requires a more refined tad model with time dependent height gradients in the wind field

propagation and amplification of tsunamis at coastal boundaries when tsunamis hit a coastal area they often cause substantial damage and loss of life at locations otherwise well protected from normal even severe wind generated waves an example of such a catastrophe took place on 12 december 1992 when an earthquake of magnitude ms 7 5 occurred in the eastern region of flores island indonesia1 2 one of the areas hardest hit by the resulting tsunamis was babi a small coastal island two villages on the island were completely destroyed even though both were located in sheltered areas where wave conditions are normally calm here we describe the results of numerical and laboratory experiments that show how unlike wind generated waves tsunamis are capable of penetrating into sheltered coastal areas without significantly losing their energy for the case of babi island the original tsunami wave was split into two with one wave propagating around each side of the island the two waves met in the sheltered region and the subsequent amplification of wave amplitude resulted in the destructive flow onto the beach

twenty five years of progress in the science of geological tsunamis following the 1992 nicaragua and flores events we review a set of 47 tsunamis of geological origin triggered by earthquakes landslides or volcanoes which have occurred over the past 25 years and provided significant new insight into theoretical experimental field or societal aspects of tsunami science among the principal developments in our command of various aspects of tsunamis we earmark the development of the w phase inversion for the low frequency moment tensor of the parent earthquake the abandonment of the concept of a maximum earthquake magnitude for a given subduction zone controlled by simple plate properties the development and implementation of computer codes simulating the interaction of tsunamis with initially dry land at beaches thus introducing a quantitative component to realistic tsunami warning procedures and the recent in situ investigation of current velocities in addition to the field of surface displacements during the interaction of tsunamis with harbors continued research remains warranted notably in the field of the real time identification of tsunami earthquakes whose tsunamis are larger than expected from their seismic magnitudes especially conventional ones the recent tragedy during the 2018 krakatau flank collapse along a scenario which had been quantitatively forecast also emphasizes the need for a continued effort in the education of the populations at risk

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

deformation partitioning during polyphase oblique convergence in the karawanken mountains southeastern alps abstract the karawanken mountains of southeastern austria straddle the insubric line a major fault zone that corresponds to the austroalpine south alpine border of the eastern alps they display polyphase structural patterns that resulted from deformation partitioning at shallow crustal levels following a poorly constrained late cretaceous deformation history paleogene contraction produced nw se trending fold thrust structures and possibly related sinistral cross faults miocene deformation produced both nw and se directed thrust faults and nw striking high angle dextral cross faults which merged with or displaced the w striking insubric line distributed dextral strike slip displacements of the order of 30 40 km and thrust displacement of 4 5 km along the northern karawanken front initiated subsidence of a small foreland basin north of the karawanken mountains recent regional deformation seems to be concentrated along cross cutting nnw striking dextral faults within a shifting system of seismogenic transfer faults that probably merge with the convergent south alpine thrust front to the west there are conspicuous parallels in the style of deformation along the karawanken mountains with that found along other seismogenic convergent strike slip faults such as those of southern california new zealand and anatolia

thrust regime and transpression regime tectonics in the tauern window eastern alps below the penninic nappes of the tauern window the deepest level of the alpine thrust system is exposed in the parautochthonous sedimentary sequence of helvetic facies

uniform sense normal simple shear of the continental lithosphere geophysical studies suggest that the thin crust characteristic of the basin and range province extends eastward beneath the west margin of the colorado plateau and rocky mountain regions in arizona and utah zones perhaps over 100 km wide may be defined bounded on the west by the east limit of upper crustal normal faults that account for more that 10 extension and on the east by the east limit of thinning beneath the colorado plateau a discrepancy exists within these zones between the negligible extension measurable in the upper crust and the substantial extension apparent from crustal thinning assuming the discrepant zone crust was as thick as or thicker than the colorado plateau rocky mountain crust prior to extensional tectonism if various theories appealing to crustal erosion are dismissed mass balance problems evident in the discrepant zones are most easily resolved by down to the east normal simple shear of the crust moving lower and middle crustal rocks that initially were within the zones up and to the west to where they now are locally exposed in the basin and range province west of the discrepant zones in both arizona and utah east directed extensional allochthons with large displacement are exposed these geophysical and geological observations complement one another if it is accepted that the entire crust in both arizona and utah failed during extension on gently east dipping east directed low angle normal faults and shear zones over a region several hundred kilometres wide large scale uniform sense normal simple shear of the crust suggests the entire lithosphere may do the same such a hypothesis predicts major lithospheric thinning without crustal thinning will occur in plateau areas in the direction of crustal shear in the case of the arizona utah and red sea extensional systems and possibly the death valley extensional terrain a broad topographic arch typically 1500 2000 m higher than the extended terrain is present suggesting lithospheric thinning in areas predicted by the hypothesis

sedimentological response to late mesozoic subduction in the penninic windows of the eastern alps late mesozoic subduction of penninic oceanic lithosphere finds its response in the sedimentary record the corresponding sediments are deposited in a deep sea trench environment and are developed as distal partly proximal flysches containing breccias and olistolites which are up to kilometer sized wildflysch in the tauern window this facies is represented by the nordrahmen zone which is the equivalent to the matrei zone it is proposed to apply the term matrei zone to the entire zone it forms the high parts of the bundner schiefer and tauernflysch formation the olistolites derive from the unstable austroalpine continental margin lower austroalpine

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

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

observation of a large density dropout across the magnetic field at 600 km altitude during the 6 7 april 2000 magnetic storm 1 the first republic of china satellite rocsat 1 at 600 km altitude observed two groups of equatorial spread f esf plasma depletion structures located in either side of the midnight meridian during the 6 7 april 2000 magnetic storm recovery phase in the group of postmidnight esf irregularities a large density dropout was observed in two consecutive rocsat orbits this large density dropout structure is similar to the density depletion event observed by defense meteorological satellite program dmsp f9 spacecraft during the 13 14 march 1989 magnetic storm greenspan et al 1991 except that the rocsat orbit traverses the magnetic field in the east west direction the postmidnight group of depletions together with the large density dropout was observed to drift westward with the background plasma at 170 m s 1 we examine the properties of the large density dropout through the plasma data taken from the drift meter dm and retarding potential analyzer rpa sensors in three consecutive orbits the apparent widening of the density depletion is explained by the different locations of the satellite within the depletion region the extreme low density level inside the upwelling depletion indicates that of the nighttime f peak passed over the rocsat orbit at 600 km the existence of no ions inside the dropout is consistent with such an elevation of the f peak

observation and model comparisons of the traveling atmospheric disturbances over the western pacific region during the 6 7 april 2000 magnetic storm 1 the ionospheric features of traveling atmospheric disturbances tads over the western pacific region have been observed by the wuhan ncu dps and cebu ionosondes and the rocsat 1 satellite during the 6 7 april 2000 magnetic storm the nighttime observations are further compared with the simulation results of the thermosphere ionosphere electrodynamics general circulation model tiegcm both observation and model demonstrate that the tads propagate equatorward with a phase speed of 610 650 m s the observations and corresponding tiegcm simulations show a negative initial correlation between nmf2 and hmf2 caused by equatorward wind surges at various locations from midlatitudes to the equator these qualitative agreements reveal that the tiegcm is capable of simulating the tads the tiegcm simulations of two locations located in the downwind hemisphere further show decreases in nmf2 and hmf2 mainly due to the enhanced transequatorial winds after lowering the f2 layer at the two locations the hmf2 is raised for several hours and shows slightly enhanced nmf2 daytime values while the meridional wind is at background magnitude we propose that this effect is caused by accumulation of plasma transported from northern latitudes however we also find that the nmf2 hmf2 and the lifetimes of hmf2 uplift phase and equatorial vertical drift in the model results are quantitatively inconsistent with that in the observed data

large scale thin skinned thrusting in the southern alps kinematic models the tectonics of the southern alps are dominated by thrusting on extensive ramp flat systems and by folding some of which is ramp folding basement slivers are involved that frontally are not thicker than 5 km the most unequivocal section is that of the grigna mountains east of lake como for which kinematic modeling based on material balance considerations results in a shortening of 40 km it is separated from the grona section in the west and the valtorta section in the east by probably pre existing transverse zones that cut through the important decollement horizons and define blocks of different depths to basement local tectonics across these transverse zones change abruptly while over all shortening remains constant in particular both east and west of the grigna section basement ramp folds were wedged into the very incompetent raibl beds provoking back thrusting of the thick hauptdolomit and higher sediments with the substitution of the original cover of the frontal limb of the basement fold this new kinematic interpretation is compatible with the information facilitates the construction of balanced sections and is required for lateral constancy of shortening

evidence for east west crustal extension in the eastern alps implications for the unroofing history of the tauern window the contact between the western border of the tauern window and the overlying austroalpine nappes austria and italy is marked by a structural petrologic and geochronologic discontinuity that developed in the early stages of unroofing of the window within the window pressure temperature time paths j selverstone 1985 indicate that significant ductile thinning occurred shortly after the cessation of thrusting paleocene eocene sense of shear indicators rotated porphyroblasts asymmetric augen and pressure shadows s c fabrics associated with a west plunging stretching lineation indicate that this thinning occurred in response to top to the west low angle normal shear during metamorphism the same sense of normal shear is present in the mesozoic members of the austroalpine sequence west of the window in these rocks however west directed shear occurred at low temperatures 300 c after the thermal peak of metamorphism structural data and the regional geometry imply that the western end of the tauern window is a low angle normal fault brenner line that juxtaposed brittlely deformed rocks of the austroalpine nappes against more ductilely deformed rocks from the window biotite k ar and rb sr data suggest a miocene age for final movement on the brenner line these data indicate a prolonged history of east west extension in the eastern alps that affected all crustal levels early ductile thinning of lower crust followed by mid to upper crustal low angle normal faulting a model is presented that relates the young east west extension to displacement transfer from dextral movement on the periadriatic lineament in this model the brenner line and by analogy the simplon line can be thought of as detachment faults that tectonically unroofed the tauern window and lepontine thermal highs respectively

tsunami generation by horizontal displacement of ocean bottom tsunami generation by an earthquake is generally modeled by water surface displacement identical to the vertical deformation of ocean bottom due to faulting the effect of horizontal deformation is usually neglected however when the tsunami source is on a steep slope and the horizontal displacement is large relative to the vertical displacement the effect becomes significant we show this for two recent earthquakes which generated much larger tsunamis than expected from seismic waves in the case of the 1994 june 2 java indonesia earthquake the focal mechanism was a very shallow dipping thrust and the source was near a very steep trench slope in the case of the 1994 nov 14 mindoro philippines earthquake strike slip faulting extended from ocean to land perpendicular to the coast line in both cases we found that the horizontal motion of slope had an important contribution to the tsunami generation

the 1674 ambon tsunami extreme run up caused by an earthquake triggered landslide we present an analysis of the oldest detailed account of tsunami run up in indonesia that of the 1674 ambon tsunami rumphius in waerachtigh verhael van de schuckelijcke aerdbebinge batavia dutch east indies 1675 at 100 m this is the largest run up height ever documented in indonesia and with over 2300 fatalities even in 1674 it ranks as one of indonesia s most deadly tsunami disasters we consider the plausible sources of earthquakes near ambon that could generate a large destructive tsunami including the seram megathrust the south seram thrust and faults local to ambon we conclude that the only explanation for the extreme run up observed on the north coast of amon is a tsunami generated by an earthquake triggered coastal landslide we use a two layer tsunami model to show that a submarine landslide with an approximate volume of 1 km3 offshore the area on ambon s northern coast between seith and hila where dramatic changes in coastal landscape were observed can explain the observed tsunami run up along the coast thus the 1674 ambon tsunami adds weight to the evidence from recent tsunamis including the 1992 flores 2018 palu and sunda strait tsunamis that landslides are an important source of tsunami hazard in indonesia

historical tsunamis and present tsunami hazard in eastern indonesia and the southern philippines 1 eastern indonesia and the southern philippines comprise a huge and seismically highly active region that has received less than the deserved attention in tsunami research compared with the surrounding areas exposed to the major subduction zones in an effort to redress the balance the tsunami hazard in this region is studied by establishing a tsunami event database which in combination with seismological and tectonic information from the region has allowed us to define and justify a number of credible worst case tsunami scenarios these scenarios have been used in numerical simulations of tsunami generation and propagation to study maximum water level along potentially affected shorelines the scenarios have in turn been combined to provide regional tsunami hazard maps in many cases the simulations indicate that the maximum water level may exceed 10 m locally and even reach above 20 m in the vicinity of the source which is of the same order as what is forecasted along the sumatra and java trenches for comparable return periods for sections of coastlines close to a source a tsunami may strike only a few minutes after it is generated providing little time for warning moreover several of the affected areas are highly populated and are therefore also high risk areas the combination of high maximum water levels short warning times dense populations and relatively short return periods suggests strongly that the tsunami hazard and risk in these regions are alarmingly high