dynamical properties of the venus mesosphere from the radio occultation experiment vera onboard venus express abstract the dynamics of venus mesosphere 60 100 km altitude was investigated using data acquired by the radio occultation experiment vera on board venus express vera provides vertical profiles of density temperature and pressure between 40 and 90 km of altitude with a vertical resolution of few hundred meters of both the northern and southern hemisphere pressure and temperature vertical profiles were used to derive zonal winds by applying an approximation of the navier stokes equation the cyclostrophic balance which applies well on slowly rotating planets with fast zonal winds like venus and titan the main features of the retrieved winds are a midlatitude jet with a maximum speed up to 140 15 m s 1 which extends between 20 s and 50 s latitude at 70 km altitude and a decrease of wind speed with increasing height above the jet cyclostrophic winds show satisfactory agreement with the cloud tracked winds derived from the venus monitoring camera vmc vex uv images although a disagreement is observed at the equator and near the pole due to the breakdown of the cyclostrophic approximation knowledge of both temperature and wind fields allowed us to study the stability of the atmosphere with respect to convection and turbulence the richardson number ri was evaluated from zonal field of measured temperatures and thermal winds the atmosphere is characterised by a low value of richardson number from 45 km up to 60 km altitude at all latitudes that corresponds to the lower and middle cloud layer indicating an almost adiabatic atmosphere a high value of richardson number was found in the region of the midlatitude jet indicating a highly stable atmosphere the necessary condition for barotropic instability was verified it is satisfied on the poleward side of the midlatitude jet indicating the possible presence of wave instability

elasticity of magnesite and dolomite from a genetic algorithm for inverting brillouin spectroscopy measurements a hybrid numerical scheme that simultaneously retrieves single crystal elastic constants cij and wave normal directions is applied to determine the elasticity of natural samples of both magnesite and dolomite as measured by brillouin spectroscopy at ambient conditions the scheme incorporates the genetic algorithm ga as a global searching tool and a final local linearization to overcome the intrinsic difficulty of fitting non linear christoffel s equation to compensate for the stochastic nature of ga especially when the misfit function of the problem manifests highly rugged topography in the model space the procedure was repeated for multi runs this is to assure that the best solution is captured by examining the statistics among the runs that yield the fittest solutions the resultant elastic constants c11 c12 c13 c14 c33 and c44 are respectively 260 3 2 6 82 9 4 5 59 6 3 1 20 1 1 3 153 7 4 1 and 59 7 1 4 gpa for magnesite for dolomite c11 c12 c13 c14 c15 c33 and c44 are respectively 204 1 2 2 68 5 3 4 45 8 4 4 20 6 1 3 6 7 1 5 97 4 5 3 and 39 1 1 5 gpa unfortunately the results for dolomite are statistically non unique in the numerical calculation the above data were adopted because the cleavage plane of dolomite was used in the experiment the results for both magnesite and dolomite are compatible with those determined earlier by ultrasonic methods it is anticipated that the new method developed in the present study should be applicable to less symmetric crystals since there are no particular assumptions on the crystal symmetry embedded within the scheme 2005 elsevier b v all rights reserved

south polar features on venus similar to those near the north pole venus has no seasons slow rotation and a very massive atmosphere which is mainly carbon dioxide with clouds primarily of sulphuric acid droplets infrared observations by previous missions to venus revealed a bright dipole feature surrounded by a cold collar at its north pole the polar dipole is a double eye feature at the centre of a vast vortex that rotates around the pole and is possibly associated with rapid downwelling the polar cold collar is a wide shallow river of cold air that circulates around the polar vortex one outstanding question has been whether the global circulation was symmetric such that a dipole feature existed at the south pole here we report observations of venus south polar region where we have seen clouds with morphology much like those around the north pole but rotating somewhat faster than the northern dipole the vortex may extend down to the lower cloud layers that lie at about 50 km height and perhaps deeper the spectroscopic properties of the clouds around the south pole are compatible with a sulphuric acid composition

tectonic interpretations of holocene marine terraces east coast of coastal range taiwan abstract the east coast of the coastal range in taiwan is well known for its multiple holocene marine terraces and their very rapid uplift the study area extends from hualien to taitung over ca 150 km of coastline here we present some new data on the age and height of holocene marine terraces and we discuss their significance for holocene coastal tectonics the holocene marine terrace sequence is subdivided into a maximum of 10 steps the highest and oldest terrace mostly underlain by transgressive deposits represents the sea level position of the culmination of holocene sea level rise and reaches up to ca 80 m above sea level transgressive deposits are radiocarbon dated at several sites back to ca 13 000 yr bp the lower terraces are mostly erosional ones overlain by thin coral beds in situ less than 1 m thick and indicate successive lowering of relative sea level during the late holocene the uplift rate of the coast is very high ranging from 5 to 15 m ka three tectonic subregions a c are identified based on the pattern of marine terrace features and uplift rate the presence of many steps during holocene time implies that intermittent uplifts associated with large earthquakes at intervals of one thousand to several hundred years have repeatedly occurred in this coastal area but with different time and amount at each subregion the uplift of subregion a resulted from an onshore active fault milun fault causative faults for the uplift of the subregions b and c are not identified offshore active faults striking obliquely to the coastline appear to be causative faults

seismogenic faults along the major suture of the plate boundary deduced by dislocation modeling of coseismic displacements of the 1951 m7 3 hualien taitung earthquake sequence in eastern taiwan abstract research at plate boundaries generally focuses on the kinematics of plate motions the genesis of large earthquake and natural resources however often the present state of knowledge is still insufficient to reveal the details of such dynamic systems to define in more detail the dynamics of a major plate boundary fault the coastal range fault eastern taiwan we use seismologic and geodetic data to unravel its subsurface geometry and relevant fault behavior by recomputing the archive triangulation datasets 1917 1978 and using a dislocation algorithm we determine that it consists of three segments our model results are consistent with the observation of the 1951 m7 3 hualien taitung earthquake sequence that the southern two segments are both oblique slip faults with significant thrust components while the northern segment is a pure strike slip fault according to our model each segment has the potential to produce an earthquake larger than m7 however based on gps observations and seismic records slip on the southern segment may take the form of aseismic creep and multiple moderate earthquakes rather than large events with long recurrence interval as occur on the two more northerly segments with regard to the central segment the epicenter distribution of catalogued earthquakes occurring after 1951 reveals the presence of a seismic gap indicating that slip on this segment is predominantly coseismic with a correspondingly higher potential for large earthquakes in the future

tectonic significance of holocene marine terraces in the coastal range eastern taiwan abstract well developed marine terraces on the coast of eastern taiwan between chengkung and hualien can be divided into three morphotectonic sectors 1 i chengkung kueian 2 ii shuilien and its vicinity 3 iii north of shuilien sector i displays at least five terrace levels and has undergone northward tilting and uplift the available 234 u 230 th and 14 c ages suggest that one of its holocene terraces rises to about 40 m and locally to 70 m above msl the average uplift rate for the holocene in this sector decreases northward from 9 10 mm yr to about 2 3 mm yr few traces of former shorelines or marine terraces higher than 5 m are found in sector ii north of shuilien in sector iii terrace elevation increases gradually and indicates an uplift rate of about 2 3 mm yr the uplift pattern agrees with geodetic data obtained between 1985 and 1988 the high uplift rates in sector i may represent compression and shortening of the northwestern corner of the philippine sea plate the low rates in sector ii may correlate with the region where the ryukyu trench meets the eastern coast of taiwan

deglacial sea level record from tahiti corals and the timing of global meltwater discharge the timing of the last deglaciation is important to our understanding of the dynamics of large ice sheets1 and their effects on the earth s surface2 3 moreover the disappearance of the glacial ice sheets was responsible for dramatic increases in freshwater fluxes to the oceans which probably disturbed the ocean s thermohaline circulation and hence global climate4 7 sea level increases bear witness to the melting of continental ice sheets but only two such records from barbados8 9 and new guinea10 11 corals have been accurately dated but these corals overlie active subduction zones where tectonic movements are large and often discontinuous especially in new guinea so the apparent sea level records may be contaminated by a complex tectonic component here we date fossil corals from tahiti which is far from plate boundaries and thus is likely to be tectonically relatively stable and remote from the locations of large former ice sheets the resulting record indicates a large sea level jump shortly before 13 800 calendar years bp which corresponds to meltwater pulse 1a in the barbados coral records8 9 the timing of this event is more accurately constrained in the tahiti record revealing that the meltwater pulse coincides with a short and intense climate cooling event12 15 that followed the initiation of the bolling allerod warm period12 16 but preceded the younger dryas cold event by about 1 000 years

late quaternary paleolandslides on the coral terraces of huon peninsula papua new guinea abstract many landslides disrupt the coral terraces at northeast huon peninsula papua new guinea each landslide is younger than the youngest terrace which it intersects and is older than the oldest coral reef or shoreline that overlies it the ages of the raised coral reefs and terraces were established by previous studies using radiocarbon and uranium series dating the times of occurrence of 26 late quaternary landslides are reported here 7 are based on new radiocarbon dates from in situ corals or molluscs associated with landslide deposits and the remainder are based on terrace ages that were established previously the landslides include slumps block slides and block flows which mostly involve failure of coral limestones of the terraces and debris flows which originate from large landslides that cut through the coral limestones into underlying fan delta and tuffaceous sedimentary rocks the proportion of terrace area affected by late quaternary landslides ranges from 50 per km2 and depends on average gradient of the landsurface tectonic uplift rate and the thickness and geometry of the raised reefs and terraces clusters of landslides which occurred at about 800 1250 and 6300 7800 yr bp may have been triggered by large earthquakes which also caused metre scale coseismic uplift however we did not identify landslides that could have been associated with every large coseimic uplift that has been documented in this region

evidence of large prehistoric offshore earthquakes deduced from uplifted holocene marine terraces in pangasinan province luzon island philippines abstract uplifted holocene marine terraces in pangasinan province westernmost luzon island philippines are reported here for the first time as geomorphic evidence of large prehistoric offshore earthquakes we recognized up to three holocene terrace steps elevations of shoreline angles are ti 1 to 5 m tii 2 to 7 m and tiii 4 to 11 m above mean sea level amsl the lateral variation in the elevation of terrace steps indicates differential uplift along the coast the staircase topography characterized by horizontal abrasion platforms meter scale terrace risers and wave cut notches suggests that these geomorphic features were formed by large coseismic uplift events terrace morphology and radiocarbon ages further suggest that at least three coseismic coastal uplift events have occurred since the culmination of the post glacial sea level rise 6000 years ago we interpret tiii to be the holocene transgressive surface 6000 ybp and estimated a maximum uplift rate of 1 7 mm yr which is almost the same as the late pleistocene uplift rate of 1 3 mm yr we infer that proximity to offshore seismic sources has contributed to the deformation pattern of holocene terraces and variation in the number of terrace steps uplift patterns of marine terraces also suggest that the magnitude and location of prehistoric earthquakes may have varied between individual coseismic uplift events we conducted simple elastic dislocation modeling to evaluate the source parameters of the causative faults our preliminary models show that a landward dipping offshore reverse fault located at the base of a steep slope separating the fore arc basin and continental shelf could be responsible for coastal uplift along the western pangasinan peninsula

venus as a more earth like planet venus is earth s near twin in mass and radius and our nearest planetary neighbour yet conditions there are very different in many respects its atmosphere mostly composed of carbon dioxide has a surface temperature and pressure far higher than those of earth only traces of water are found although it is likely that there was much more present in the past possibly forming earth like oceans here we discuss how the first year of observations by venus express brings into focus the evolutionary paths by which the climates of two similar planets diverged from common beginnings to such extremes these include a co2 driven greenhouse effect erosion of the atmosphere by solar particles and radiation surface atmosphere interactions and atmospheric circulation regimes defined by differing planetary rotation rates

densities and temperatures in the venus mesosphere and lower thermosphere retrieved from soir on board venus express retrieval technique the soir instrument flying on board venus express operates in the infrared spectral domain and uses the solar occultation technique to determine the vertical profiles of several key constituents of the venus atmosphere the retrieval algorithm is based on the optimal estimation method and solves the problem simultaneously on all spectra belonging to one occultation sequence vertical profiles of h2o co hcl and hf as well as some of their isotopologues are routinely obtained for altitudes ranging typically from 70 to 120 km depending on the species and the spectral region recorded in the case of co2 a vertical profile from 70 up to 150 km can be obtained by combining different spectral intervals rotational temperature is also retrieved directly from the co2 signature in the spectra the present paper describes the method used to derive the above mentioned atmospheric quantities and temperature profiles the method is applied on some retrieval cases illustrating the capabilities of the technique more examples of results will be presented and discussed in a following companion paper which will focus on the co2 vertical profiles of the whole data set

venus s southern polar vortex reveals precessing circulation initial images of venus s south pole by the venus express mission have shown the presence of a bright highly variable vortex similar to that at the planet s north pole using high resolution infrared measurements of polar winds from the venus express visible and infrared thermal imaging spectrometer virtis instrument we show the vortex to have a constantly varying internal structure with a center of rotation displaced from the geographic south pole by 3 degrees of latitude and that drifts around the pole with a period of 5 to 10 earth days this is indicative of a nonsymmetric and varying precession of the polar atmospheric circulation with respect to the planetary axis

early holocene catastrophic mass wasting event and fan delta development on the hua tung coast eastern taiwan abstract landslides and debris flows rarely occurred during historical times in the tectonically active coastal range of eastern taiwan this topographic stability however contrasts greatly with the widespread existence of terraced alluvial fans and fan deltas on the hua tung coast which fringes the range this study focuses on the two largest fan terrace systems on the hua tung coast both of which consist of alluvial fans plane view areas up to 8 km 2 larger than their contributing catchments stratigraphic data show that both systems were in sandy wave dominated settings during de glacial times the systems were then disturbed by a catastrophic landslide debris flow event or events which brought enormous amounts of gravel facies gm into the systems deforming previously deposited marine sands facies sm and shallowing the seafloor the combined gm sm complex yields multiple radiocarbon dates ranging from 11 3 to 8 3 ka cal bp with a cluster around 8 6 ka cal bp this mass wasting event has been unique since the emergence of its contributing catchment 0 2 0 3 ma ago the low frequency of such an event could reflect the great resistance of rock mass in the source areas to weathering and erosion the common blockage of valley floors by giant boulder piles which limits channel incision and sediment transport could also increase the apparent stability of the mountain the trigger of landslides in the coastal range has been linked to large earthquakes additionally we propose that the great magnitude and duration of the observed early holocene event were caused by the contemporaneous prolonged rainfall and or high frequency of typhoons associated with the east asian summer monsoon maximum

zonal winds in the middle atmosphere of venus from pioneer venus radio occultation data abstract pioneer venus radio occultation data for four seasons between december 1978 and october 1981 are used to construct meridional cross sections of temperature and zonal wind velocity for the middle atmosphere of venus in the altitude range of 40 80 km and in the latitude range of 1 5 85 wind speeds are derived assuming cyclostrophic balance the wind field contains as many as three jets first a prominent one above the clouds situated between 50 and 55 latitude with a maximum speed of 140 m s 1 a second with a speed of 95 m s 1 centered at 70 and at 60 km altitude and a possible third jet at 15 and 65 km altitude with a speed of 100 m s 1 the notable midlatitude jet is associated with the cold polar collar wind speeds above 70 km generally decrease with height because of the warm pole at these levels however within the jet the speed is 100 m s 1 at 83 km the jets may be barotropically unstable and inertial instability may occur above the clouds on the equatorial side of the main

sunlight refraction in the mesosphere of venus during the transit on june 8th 2004 abstract many observers in the past gave detailed descriptions of the telescopic aspect of venus during its extremely rare transits across the solar disk in particular at the ingress and egress the portion of the planet s disk outside the solar photosphere has been repeatedly perceived as outlined by a thin bright arc aureole those historical visual observations allowed inferring the existence of venus atmosphere the bright arc being correctly ascribed to the refraction of light by the outer layers of a dense atmosphere on june 8th 2004 fast photometry based on electronic imaging devices allowed the first quantitative analysis of the phenomenon several observers used a variety of acquisition systems to image the event ranging from amateur sized to professional telescopes and cameras thus collecting for the first time a large amount of quantitative information on this atmospheric phenomenon in this paper after reviewing some elements brought by the historical records we give a detailed report of the ground based observations of the 2004 transit besides confirming the historical descriptions we perform the first photometric analysis of the aureole using various acquisition systems the spatially resolved data provide measurements of the aureole flux as a function of the planetocentric latitude along the limb a new differential refraction model of solar disk through the upper atmosphere allows us to relate the variable photometry to the latitudinal dependency of scale height with temperature in the south polar region as well as the latitudinal variation of the cloud top layer altitude we compare our measurements to recent analysis of the venus express virtis m vmc and spicav soir thermal field and aerosol distribution our results can be used a starting point for new more optimized experiments during the 2012 transit event

an igneous origin for features of a candidate crater lake system in western memnonia mars the association of channels inner terraces and delta like features with martian impact craters has previously been interpreted as evidence in favor of the past existence of crater lakes on mars however examination of a candidate crater lake system in western memnonia suggests instead that its features may have formed through igneous processes involving the flow and ponding of lava accumulations of material in craters and other topographic lows throughout much of the study region have characteristics consistent with those of volcanic deposits and terraces found along the inner flanks of some of these craters are interpreted as having formed through drainage or subsidence of volcanic materials channels previously identified as inlets and outlets of the crater lake system are interpreted instead as volcanic rilles these results challenge previous interpretations of terrace and channel features in the study region and suggest that candidate crater lakes located elsewhere should be reexamined

late quaternary coseismic uplift events on the huon peninsula papua new guinea deduced from coral terrace data up to six regressive terraces occur on the holocene raised reef tract and up to 15 occur on late pleistocene raised reef tracts along 40 km of coastline at huon peninsula papua new guinea we suggest that the regressive terraces represent repeated episodic uplift caused by great earthquakes ages of holocene coseismic uplift events are established by radiocarbon dating the late pleistocene events are bracketed by u series ages of the raised reef tracts on which they occur the mean recurrence interval of great earthquakes that caused the uplift events is 970 to 1165 years in the holocene and probably the same in the late pleistocene the interval ranged from about 200 to 1900 years the uplift rate increases parallel to the coast from northwest to southeast and the amplitude of coseismic uplifts generally increases similarly although some events produced uplift with little shore parallel tilting the mean amplitude of coseismic uplifts throughout the study area is 3 m in for both holocene and late pleistocene sequences large late quaternary landslides are numerous and some probably were triggered by the great earthquakes that caused coseismic uplift there appears to be no continuum between historical large earthquakes at huon peninsula of magnitudes 7 that produced no or only minor uplift and the great earthquakes represented by meter scale coseismic uplifts and very large landslides two tectonic subregions are recognized which were uplifted together by some holocene events but not by others there is no surface trace of holocene faulting between the subregions and a buried fault is thought to separate them

high altitude venus haze from pioneer venus limb scans abstract high vertical resolution scans of the venus limb made by the pioneer venus orbiter cloud photopolarimeter at 365 nm and 690 nm wavelengths are used to investigate the level of the haze top and haze particle properties and scale height haze particle vertical optical depth 0 01 occurs at altitude 80 to 85 km based on knowledge of instrument pointing the lowest haze tops were observed close to subsolar longitudes but the data set supports a longitude dependence no more than a temporal variation single scattering computations for a spherical shell atmosphere show good agreement with observed intensities for particles smaller than 0 3 m radius and refractive index less than 1 7 consistent with but not limited to concentrated sulfuric acid particle scale height in the 0 5 to 2 mbar pressure regions varies between 1 and 3 km over the season 12 of 92 days latitude 15 45 n and local time 0900 1800 ranges of the observations detached layers of haze are sometimes present an average particle scale height of 2 2 km at 84 km altitude yields an eddy diffusion coefficient of 1 3 10 5 cm 2 sec 1

cyclostrophic winds from the visible and infrared thermal imaging spectrometer temperature sounding a preliminary analysis 1 visible and infrared thermal imaging spectrometer virtis onboard the venus express spacecraft has been operating since april 2006 providing new observations of the temperature structure of venus mesosphere 60 95 km zonal winds in the middle atmosphere of venus have been retrieved from virtis temperature profiles using the cyclostrophic approximation the wind field is characterized by three main features 1 a midlatitude jet connected to the thermal feature known as the cold collar the jet reaches a maximum speed of 80 90 10 m s near the cloud top 70 km altitude at 50 s latitude 2 a strong decrease of wind from 60 s toward the pole reaching zero velocity at 70 s and 3 the decrease of the wind above the jet with increasing altitude local time dependence of the temperature and wind field has been analyzed temperatures show at cloud tops a cooling of 15 k during the night which propagates also on the zonal wind field comparison with cloud tracked winds from venus monitoring camera images indicates a first order agreement

holocene sea level rise and coral reef growth on a tectonically rising coast huon peninsula papua new guinea abstract eighty eight conventional radiocarbon age measurements of corals collected from holocene transgressive reefs at huon peninsula have been published previously but except for 29 dates from a 52 m drillhole the data have not been systematically analysed from these data we show that post glacial reef growth tracked rising sea level keep up growth at huon peninsula from 70 m at 11 200 yr bp the holocene reef emerged about 6300 yr bp in the southeast of the region where uplift rate is highest 3 3 m ka 1 and at about 5950 yr bp in the northwest where uplift rate is 1 9 m ka 1 the uplift process is dominated by metre scale coseismic uplift events the difference in timing of reef emergence between northwest and southeast is related to differences in the stepwise uplift of the two regions although uplift is stepwise the uplift corrected age height data from the dated corals fall within a tight envelope which represents a well defined eustatic sea level curve for the calibrated age interval from 7000 to 13 000 yr bp

velocity field of gps stations in the taiwan area abstract the 131 stations of the taiwan gps network were surveyed 4 6 times from 1990 to 1995 with dual frequency geodetic receivers the standard deviation of an observed baseline length with its linear trend removed is in the range of 6 10 mm for a 3 120 km long baseline the average rates of length change for all baselines of the network and those from nine continuously monitoring permanent stations are used in a least squares adjustment to estimate the velocities of the gps stations relative to paisha penghu situated at the chinese continental margin to the south of fengping in the northern coastal range the velocity vectors of stations in lanhsu lutao and the coastal range trend in the directions of 306 322 with rates of 56 82 mm yr in contrast there is a dramatic decrease in the rates to the north of fengping this may be caused by the motion along the ne sw trending thrusts which obliquely cut the northern coastal range a discontinuity of about 30 mm yr in the rates along with a remarkable change in the directions of station velocity is observed across the longitudinal valley then the moving directions gradually shift to the west for the stations in the western foothills in the kaohsiung pingtung coastal area the station velocities are even directed toward the southwest to the north of the peikang high the velocity vectors of the stations change direction from the west gradually to the north and finally to the east and southeast significant nw se extensional deformation is found in the ilan plain and northern taiwan in general the pattern of the velocity field for gps stations in the taiwan area is quite consistent with the directions of present day tectonic stress

fossil tubeworms link coastal uplift of the northern noto peninsula to rupture of the wajima oki fault in ad 1729 abstract the active fault zone on the seafloor off the northern coast of the noto peninsula of central japan is divided into four segments from west to east monzen oki saruyama oki wajima oki and suzu oki to examine the latest event that occurred in these segments we investigated the dates and elevations of fossilized intertidal tubeworms along the northern coast of the noto peninsula located on the hanging wall sides of the faults using radioactive carbon dating and global positioning measurements for each fossil we calculated the difference between the past and present elevation thereby estimating the elevation of the sea level at the date of the fossil using a curve for sea level change this calculation provided us with the elevation change at each site the vertical changes estimated from the elevations and ages of the intertidal tubeworms revealed that the coastal emergence probably occurred between 1600 and 1800 ad this area of coastal emergence lies adjacent to active faults within the wajima oki segment a model for rectangular faults with three fault planes and a moment magnitude of 6 6 for the wajima oki segment reproduced the observed pattern of coastal emergence well only one damaging earthquake that in 1729 is known to have occurred in this part of the northern noto peninsula between 1600 and 1800 ad and there has not been one since 1800 ad the slip distribution of the fault predicted by the model is consistent with the distribution of shaking related damage documented in 1729 we conclude that rupture of the wajima oki segment caused the 1729 earthquake

holocene tectonic uplift deduced from elevated shorelines eastern coastal range of taiwan abstract this paper is concerned with the tectonic trends that can be deduced from the holocene raised shorelines between ch eng kung and hsin she along a 65 km long coastal sector in the eastern coastal range of taiwan sequences of up to eight superimposed shorelines have been identified in a single section twelve new radiocarbon dates six of which were obtained by accelerator mass spectrometry of in situ marine samples up to 40 m in altitude have confirmed a holocene age however it is difficult to define clearly the upper marine boundary in the highest holocene coastal terraces which have been uplifted to 65 70 m but have been capped by and often also interfingered with alluvial deposits high uplift rates ranging from 2 5 3 0 to over 8 mm yr have been inferred along the coast providing evidence of differential uplift in some cases uplift movements appear to have occurred by steps probably spasmodically recurrence periods of fast uplifts seem to be of the order of at most 1000 yr this means that a new spasmodic movement may be imminent because the last displacement 4 6 m has been dated about 1000 yr bp

holocene paleoseismicity in the fold and thrust belt of the hikurangi subduction zone eastern north island new zealand abstract along the 500 km long eastern coastline of the north island new zealand there are at most seven distinct holocene marine terraces aged 7 ka b p or less the highest of the terraces is 27 m above present day mean sea level the coastal region is subdivided into fourteen distinct subregions based on radiocarbon ages of marine deposits overlying wave cut shore platforms and geographic distribution of similarly aged terraces holocene marine terraces are the result of uplift associated with large earthquakes co seismic deformation this conclusion is based on characteristic stepped terrace morphology clustering of ages of terrace deposits within subrogions and the occurrence of co seismic uplift in historic time differential uplift across structures and distinct age variations at subregion boundaries are also characteristic recurrence intervals of uplift in any one terrace sequence vary from 0 4 ka to 2 0 ka and individual amounts of uplift vary from 1 0 m to 4 0 m in the past 2 5 ka ages from all terraces within subrogions indicate at least 21 paleoseismic events affecting coastal areas of eastern north island in that period these events cluster in time and in separate parts of eastern north island several earthquakes occurred 0 3 0 6 1 0 1 5 2 1 and 2 3 ka b p our data strongly support the concept of segmentation of deformation along the subduction margin the likely cause of coastal uplift is movement on steep reverse faults local structures rather than the subduction thrust that propagate from or near the subduction thrust some 20 25 km below the region earthquakes of moment magnitude 7 3 8 0 are estimated to be associated with these fault movements

the two titan stellar occultations of 14 november 2003 1 we report the observation of two stellar occultations by titan on 14 november 2003 using stations in the indian ocean southern africa spain and northern and southern americas these occultations probed altitudes between 550 and 250 km 1 to 250 bar in titan s upper stratosphere the light curves reveal a sharp inversion layer near 515 6 km altitude 1 5 bar pressure level where the temperature increases by 15 k in only 6 km this layer is close to an inversion layer observed fourteen months later by the huygens hasi instrument during the entry of the probe in titan s atmosphere on 14 january 2005 fulchignoni et al 2005 central flashes observed during the first occultation provide constraints on the zonal wind regime at 250 km with a strong northern jet 200 m s 1 around the latitude 55 n wind velocities of 150 m s 1 near the equator and progressively weaker winds as more southern latitudes are probed the haze distribution around titan s limb at 250 km altitude is close to that predicted by the global circulation model of rannou et al 2004 in the southern hemisphere but a clearing north of 40 n is necessary to explain our data this contrasts with rannou et al s 2004 model which predicts a very thick polar hood over titan s northern polar regions simultaneous observations of the flashes at various wavelengths provide a dependence of q with q 1 8 0 5 between 0 51 and 2 2 m for the tangential optical depth of the hazes at 250 km altitude

stratigraphic modeling of the western taiwan foreland basin sediment flux from a growing mountain range and tectonic implications abstract sediment flux signals from source to sink in foreland basins preserve a record of tectonics sea level and climate through erosion and sedimentation however longitudinal sediment transport often occurs in foreland basins thus removing part of the orogenic material flux from foreland basin records here we use mass balance calculation and stratigraphic simulations of sediment fluxes for the taiwan orogen to provide an order of magnitude estimate of how much orogenic material may bypass a foreland basin our results indicate a significant potentially more than 50 mismatch between sediment volume currently preserved in the basin and the amount of material presumably eroded from the orogen since the onset of collision in taiwan this suggests either a significant overestimation of average erosion rates over the period concerned with orogenic development of taiwan or it supports previous paleogeographic work suggesting that longitudinal sediment transport in the paleo taiwan strait served as a major bypass conduit of importance for the establishment of a steady state orogen we identify candidate submarine topography in the south china sea that may preserve taiwan s missing erosional mass

the thermal structure of the venus atmosphere intercomparison of venus express and ground based observations of vertical temperature and density profiles the venus international reference atmosphere vira model contains tabulated values of temperature and number densities obtained by the experiments on the venera entry probes pioneer venus orbiter and multi probe missions in the 1980s the instruments on the recent venus express orbiter mission generated a significant amount of new observational data on the vertical and horizontal structure of the venus atmosphere from 40 km to about 180 km altitude from april 2006 to november 2014 many ground based experiments have provided data on the upper atmosphere 90 130 km temperature structure since the publication of vira in 1985 the thermal structure of the venus atmosphere team was supported by the international space studies institute issi bern switzerland from 2013 to 2015 in order to combine and compare the ground based observations and the vex observations of the thermal structure as a first step towards generating an updated vira model results of this comparison are presented in five latitude bins and three local time bins by assuming hemispheric symmetry the intercomparison of the ground based and vex results provides for the first time a consistent picture of the temperature and density structure in the 40 km 180 km altitude range the venus express observations have considerably increased our knowledge of the venus atmospheric thermal structure above 40 km and provided new information above 100 km there are however still observational gaps in latitude and local time above certain regions considerable variability in the temperatures and densities is seen above 100 km but certain features appear to be systematically present such as a succession of warm and cool layers preliminary modeling studies support the existence of such layers in agreement with a global scale circulation the intercomparison focuses on average profiles but some vex experiments provide sufficient global coverage to identify solar thermal tidal components the differences between the vex temperature profiles and the vira below 0 1 mbar 95 km are small there is however a clear discrepancy at high latitudes in the 10 30 mbar 70 80 km range the vex observations will also allow the improvement of the empirical models vts3 by hedin et al 1983 and vira by keating et al 1985 above 0 03 mbar 100 km in particular the 100 150 km region where a sufficient observational coverage was previously missing the next steps in order to define the updated vira temperature structure up to 150 km altitude are 1 define the grid on which this database may be provided 2 fill what is possible with the results of the data intercomparison and 3 fill the observational gaps an interpolation between the datasets may be performed by using available general circulation models as guidelines an improved spatial coverage of observations is still necessary at all altitudes in latitude longitude and at all local solar times for a complete description of the atmospheric thermal structure in particular on the dayside above 100 km new in situ observations in the atmosphere below 40 km are missing an altitude region that cannot be accessed by occultation experiments all these questions need to be addressed by future missions

modern vertical deformation rates and mountain building in taiwan from precise leveling and continuous gps observations 2000 2008 1 to characterize the present day vertical displacement field in the active taiwan orogenic belt 1843 precise leveling and 199 continuous gps measurements from 2000 to 2008 are collected and analyzed in this study vertical velocities derived from the leveling data are placed in a reference frame of the chinese continental margin using continuous gps observations at nearby sites the leveling and gps vertical velocities generally reveal a dome shaped pattern with uplift of 0 2 18 5 mm yr in the interior of the mountain range and subsidence on the flanks of the mountains and coastal plains modern uplift rates in the active fold and thrust belt are generally consistent with geologic uplift rates however present day uplift rates in the central range are faster than the million years averaged exhumation rates the modern subsidence rates are generally consistent with geologic rates except for the rates in western coastal areas due to groundwater pumping present day subsidence in the southern central range and northern coastal range is however inconsistent with long term uplift which may reflect interseismic elastic strain accumulation across faults present day subsidence in northern taiwan occurs in a region of postcollisional orogenic collapse we model the present day and geologic vertical velocities and published gps horizontal velocity data across southern taiwan using a 2 d lithospheric model the model suggests a combined slip rate of 40 mm yr on the frontal thrusts and 45 mm yr on the longitudinal valley fault the model requires an additional source of crustal thickening under the central range to match the observed present day uplift rates

new insights into holocene marine terrace development caused by seismic and aseismic faulting in the coastal range eastern taiwan abstract the coastal range in eastern taiwan which has resulted from arc continent collisions involves well developed holocene uplifted marine terraces along a 140 km long stretch of the coast this is the first study that unraveled the aseismic generation of marine terraces associated with coseismic uplift along the creeping fault we organized dems lidar mapping and field surveys to obtain detailed and systematic measurements of the inner and outer edges and wave cut platform elevations along thirty three stream profile transects allowing us to locate the bedrock profile spatial and temporal variations in the 14c age are characterized by an offlapping built feature of significant seaward younging trend of ages across the marine terrace caused by aseismic and coseismic uplift thus heights of the bedrock riser and platform are caused by coseismic large earthquake and aseismic plus moderate coseismic vertical deformations during a large earthquake cycle respectively this indicates that each terrace duration and paleoshoreline ages can be used to infer the recurrence interval and the timing of large earthquake events respectively results of the age of the paleoshoreline indicate six paleoseismic events at 8500 6300 4800 3400 1700 and 700 yr bp this implies that the chihshang creeping fault could be capable of producing large earthquakes greater than m7 at millennial time scales associated with larger coseismic deformations the creep faulting associated with seismic and aseismic uplift is a dominant process constraining the holocene marine terrace evolution

modes rates and geomorphological consequences of active tectonics in the marmara region nw turkey a critical overview based on seismotectonic field observations abstract the marmara region is a tectonically active belt in northwestern turkey where field evidence of the collusion escape and strike slip tectonics is manifested the effect of tectonics on the modification of coastal and morphological features of nw turkey is although extensive relatively unknown and rarely appreciated active tectonics in the region has normal and reverse forms of dip slip namely uplift and subsidence and strike slip as is plainly demonstrated by the 1999 marmara earthquake sequence along the north anatolian fault naf these tectonic effects are presently related to the geometry of the naf the mode of lateral movement along it and proximity to the fault the 1999 earthquakes provided data indicating that over a return period of about 250 years seismotectonic strike slip movements recur up to 5 m and dip slip movements up to 2 6 m suggesting the rate of tectonics along the naf in the marmara region is on the order of 20 mm a for strike slip and 10 mm a for dip slip movements these rates are sufficiently large to form during the late quaternary prominent features of the landscape in the marmara region

holocene coral reef terraces and coseismic uplift of huon peninsula papua new guinea abstract as many as six levels of emerged holocene coral terraces occur along 40 km of coastline on the huon peninsula papua new guinea recording uplift history since culmination of the postglacial transgression the holocene reef crest ca 6000 yr b p is tilted down to the northwest parallel to the coast and concordant with the deformation of the last interglacial coral reef terrace and descends from 23 to 12 m in the study area the pattern and rate of deformation have been uniform in the late quaternary because average uplift rates have remained the same since the last interglaciation the holocene terraces described here are erosional features with regressive encrusting corals developed upon the holocene transgressive reef the multiple levels represent episodic probably coseismic uplift which has occurred repeatedly in the last ca 6000 yr significant longshore variation in the age of the lowest terrace from 1700 to 2500 yr b p suggests independent coseismic uplift on different sectors of the coast this is supported by age height relationships of the higher holocene terraces nonlinear uplift during the holocene with recurrence intervals increasing toward the present is clearly recorded by the regressive terraces in each subregion some of the holocene regressive terraces grade laterally into fluvial terraces capped with debris flow deposits probably reflecting seismically triggered mass movement

marine deposits of late glacial times exposed by tectonic uplift on the east coast of taiwan abstract marine sediments deposited some 14 000 years ago when the sea level was between 80 and 100 m below the present sea level have been found exposed at about 17 m in altitude near tu lan on the east coast of taiwan this implies a minimum average uplift rate of 7 6 0 9 mm yr similar values of tectonic uplift are not uncommon on the eastern coastal range of taiwan such rates of tectonic uplift among the highest reported in the literature are of the same order as present day maximum glacio isostatic uplift rates

structure of the venus neutral atmosphere as observed by the radio science experiment vera on venus express 1 the european space agency venus express radio science experiment vera obtained 118 radio occultation measurements of the venusian atmosphere between july 2006 and june 2007 southern latitudes are uniformly sampled measurements in the northern hemisphere are concentrated near the pole radial profiles of neutral number density derived from the occultations cover the altitude range 40 90 km which are converted to profiles of temperature t and pressure p versus height h profiles of static stability are found to be latitude dependent and nearly adiabatic in the middle cloud region below the clouds the stability decreases at high latitudes at an altitude of 65 km the vera t p h profiles generally lie between the venus international reference atmosphere vira and vira 2 models the retrieved temperatures at any given pressure level typically are within 5 k of those derived from the pioneer venus orbiter radio occultation experiments a large equator to pole temperature contrast of 30 k is found at the 1 bar 1000 hpa level the vera observations reveal a distinct cold collar region in the southern hemisphere complementing that in the north at the latitudes of the cold collars the tropopause altitude increases relative to higher and lower latitudes by 7 km while the temperature drops roughly 60 k the observations indicate the existence of a wave number 2 structure poleward of 75 latitude at altitudes of 62 km

review of paleoseismological and active fault studies in taiwan in the light of the chichi earthquake of september 21 1999 abstract this paper reviews the research on active and earthquake faults in taiwan conducted prior and after the 1999 chichi earthquake the chichi earthquake plays as a turning point of the relevant studies since the 1999 coseismic surface rupture exactly follows preexisting fault scarps created in turn by previous seismic events along the chelungpu fault this fact indicates that the precise mapping on the other active faults is fundamental to predict the location of surface rupture caused by large future earthquakes since 1999 many trenching studies have been carried out along the chichi earthquake fault a few of them demonstrates that the penultimate event is as young as probably only 200 430 years old however some others show a rather old age of several hundreds years or even older for the last faulting event before 1999 more trenching studies are necessary for such a long fault in order to understand the possible segmentation features and the correlation of the paleoseismic events identified along the entire fault length in addition we further discuss the offshore faulting associated with seismic event along the eastern coast of taiwan where the multiple holocene terraces are well known

a model for the termination of the ryukyu subduction zone against taiwan a junction of collision subduction separation and subduction boundaries 1 the nw moving philippine sea plate psp collides with the eurasian plate eup in the vicinity of taiwan and at the same time it subducts toward the north along sw ryukyu the ryukyu subduction zone terminates against eastern taiwan while the ryukyu trench is a linear bathymetric low about 100 km east of taiwan closer to taiwan it cannot be clearly identified bathymetrically owing to the deformation related to the collision making the location of the intersection of the ryukyu with taiwan difficult to decipher we propose a model for this complex of boundaries on the basis of seismicity and 3 d velocity structures in this model the intersection is placed at the latitude of about 23 7 n placing the northern part of the coastal range on eup as psp gets deeper along the subduction zone it collides with eup on the taiwan side only where they are in direct contact thus the eurasian plate on the taiwan side is being pushed and compressed by the nw moving philippine sea plate at increasing depth toward the north offshore of northeastern taiwan the wedge shaped eup on top of the ryukyu subducting plate is connected to the eup on the ryukyu side and coupled to the nw moving psp by friction at the plate interface the two sides of the eup above the western end of the subduction zone are not subjected to the same forces and a difference in motions can be expected the deformation of taiwan as revealed by continuous gps measurements geodetic movement along the east coast of taiwan and the formation of the hoping basin can be understood in terms of the proposed model

age and height distribution of holocene transgressive deposits in eastern north island new zealand abstract holocene transgressive deposits are frequently exposed near the present day coastline of the study area along eastern north island new zealand they occur in sites of former estuaries that were filled during the postglacial rise in sea level we present one hundred radiocarbon dates of holocene transgressive deposits from the study area ranging in age from ca 10 000 to 5500 yr b p relative sea level curves up to ca 6000 yr b p were reconstructed for six locations the curves have similar slopes prior to about 7000 yr b p indicating that sea level rise was much more rapid than any tectonic uplift at that time the postglacial rise in sea level in new zealand is considered in general to have culminated at about 6500 yr b p but the upper limit ages of transgressive deposits in our study area vary from ca 5500 to 7000 yr b p at sites where the uplift rate is high the postglacial transgression culminated rather earlier than ca 6500 yr b p and at sites where there is subsidence or there is very low uplift the culmination is later than ca 6500 yr b p nine of fourteen dates from fossil trees in growth position that grew in and were buried by estuarine silt cluster in the age range ca 8000 8400 yr b p these data support the view that there was a minor regression or stillstand in the eustatic sea level rise at that time eleven tectonic subregions are recognized in the study area on the basis of average uplift rate most of these subregions coincide with those established from the number and ages of younger holocene marine terraces of probable coseismic origin

altimetry of the venus cloud tops from the venus express observations 1 simultaneous observations of venus by visible and infrared thermal imaging spectrometer and venus monitoring camera onboard the venus express spacecraft are used to map the cloud top altitude and to relate it to the ultraviolet uv markings the cloud top altitude is retrieved from the depth of co2 absorption band at 1 6 m in low and middle latitudes the cloud top is located at 74 1 km it decreases poleward of 50 and reaches 63 69 km in the polar regions this depression coincides with the eye of the planetary vortex at the same latitude and hour angle cloud top can experience fast variations of about 1 km in tens of hours while larger long term variations of several kilometers have been observed only at high latitudes uv markings correlate with the cloud altimetry however the difference between adjacent uv dark and bright regions does not exceed several hundred meters surprisingly co2 absorption bands are often weaker in the dark uv features indicating that these clouds may be a few hundred meters higher or have a larger scale height than neighboring clouds ultraviolet dark spiral arms which are often seen at about 70 correspond to higher altitudes or to the regions with strong latitudinal gradient of the cloud top altitude cloud altimetry in the polar region reveals the structure that correlates with the thermal emission maps but is invisible in uv images this implies that the uv optically thick polar hood is transparent in the near ir

coastal uplift mechanisms at pakarae river mouth constraints from a combined holocene fluvial and marine terrace dataset abstract one of the major environmental controls on sedimentary systems is tectonics and thus in order to make quantitative explanations and predictions of the behaviour of sedimentary systems it is important to quantify tectonic rates and mechanisms in this study we show how a combined holocene fluvial and marine terrace dataset can be used to place constraints on coastal uplift mechanisms at pakarae river mouth to the east of the waipaoa sedimentary system mapping and surveying of fluvial terraces shows that the terraces can be divided into three sets i pgt a fill terrace formed during post glacial sea level rise 10000 7000 cal yr bp ii a sequence of post 7000 cal yr bp degradation terraces and iii historical post ad 1880 flood terraces a conceptual model of terrace evolution proposes that coseismic uplift has resulted in the observed back tilting downstream divergence and successive abandonment of tectonic terraces coastal uplift mechanisms are then examined by comparing the fluvial and marine terrace uplift distribution and the uplift per event from the marine terraces with those predicted by forward elastic dislocation models the models agree with the interpretation that the terrace uplift can be explained by coseismic slip on a steeply west dipping reverse fault located close to the shore possibly in combination with rupture of the hikurangi margin subduction interface 10 24 km below this study also provides insights into the tectonic drivers and impacts on the adjacent waipaoa sedimentary system including the possible role of subduction earthquakes growth of structures on the shelf and upper slope and the role that the interplay between sea level and tectonic controls has on sediment dispersal

late holocene coseismic uplift on the hua tung coast eastern taiwan evidence from mass mortality of intertidal organisms abstract the evidence of coseismic uplift on the dynamic wave dominated hua tung coast fringing the active coastal range eastern taiwan has been equivocal due to complex controls by wave and terrestrial sediment over morphological and ecological systems of the coast this study by applying radiocarbon dating methods demonstrates coseismic uplift nature of the coast by finding synchronously killed intertidal organisms mostly boring shell jouannetia sp stranded at different sites of the coast with distinct physiographic characters based on these data together with evidence from wave cut notch sequences two coseismic uplift systems are recognized one centers around the northern middle part of the coast and yields events with uplift amounts of maximal 3 6 m and an average recurrence interval of at least several hundred years the most recent activity of this system influencing at least 70 km of coast occurred at 0 9 ka the earthquake generating this event also triggered extensive landslides debris flows in the region another system exemplified by the uplift associated with the 2003 cheng kung earthquake centers on the southern part of the coast and yields uplift of likely