upper crustal structure in puget lowland washington results from the 1998 seismic hazards investigation in puget sound a new three dimensional 3 d model shows seismic velocities beneath the puget lowland to a depth of 11 kin the model is based on a tomographic inversion of nearly one million first arrival travel times recorded during the 1998 seismic hazards investigation in puget sound ships allowing higher resolution mapping of subsurface structures than previously possible the model allows us to refine the subsurface geometry of previously proposed faults e g seattle hood canal southern whidbey island and devils mountain fault zones as well as to identify structures tacoma lofall and sequim fault zones that warrant additional study the largest and most important of these newly identified structures lies along the northern boundary of the tacoma basin we informally refer to this structure here as the tacoma fault zone although tomography cannot provide information on the recency of motion on any structure holocene earthquake activity on the tacoma fault zone is suggested by seismicity along it and paleoseismic evidence for abrupt uplift of tidal marsh deposits to its north the tomography reveals four large west to northwest trending low velocity basins tacoma seattle everett and port townsend separated by regions of higher velocity ridges that are coincident with fault bounded uplifts of eocene crescent formation basalt and pre tertiary basement the shapes of the basins and uplifts are similar to those observed in gravity data gravity anomalies calculated from the 3 d tomography model are in close agreement with the observed anomalies in velocity cross sections the tacoma and seattle basins are asymmetric the basin floor dips gently toward a steep boundary with the adjacent high velocity uplift locally with a velocity overhang that suggests a basin vetgent thrust fault boundary crustal fault zones grow from minor folds into much larger structures along strike inferred structural relief across the tacoma fault zone increases by several kilometers westward along the fault zone to lynch cove where we interpret it as a zone of south vergent faulting overthrusting tacoma basin in contrast structural relief along the seattle fault zone decreases west of seattle which we interpret as evidence that the n s directed compression is being accommodated by slip transfer between the seattle and tacoma fault zones together the tacoma and seattle fault zones raise the seattle uplift one of a series of east west trending pop up structures underlying puget lowland from the black hills to the san juan islands

active tectonics of the seattle fault and central puget sound washington implications for earthquake hazards we use an extensive network of marine high resolution and conventional industry seismic reflection data to constrain the location shallow structure and displacement rates of the seattle fault zone and crosscutting high angle faults in the puget lowland of western washington analysis of seismic profiles extending 50 km across the puget lowland from lake washington to hood canal indicates that the west trending seattle fault comprises a broad 4 6 km zone of three or more south dipping reverse faults quaternary sediment has been folded and faulted along all faults in the zone but is clearly most pronounced along fault a the northernmost fault which forms the boundary between the seattle uplift and seattle basin analysis of growth strata deposited across fault a indicate minimum quaternary slip rates of about 0 6 mm yr slip rates across the entire zone are estimated to be 0 7 1 1 mm yr the seattle fault is cut into two main segments by an active north trending high angle strike slip fault zone with cumulative dextral displacement of about 2 4 km faults in this zone truncate and warp reflections in tertiary and quaternary strata and locally coincide with bathymetric lineaments cumulative slip rates on these faults may exceed 0 2 mm yr assuming no other crosscutting faults this north trending fault zone divides the seattle fault into 30 40 km long western and eastern segments although this geometry could limit the area ruptured in some seattle fault earthquakes a large event ca a d 900 appears to have involved both segments regional seismic hazard assessments must 1 incorporate new information on fault length geometry and displacement rates on the seattle fault and 2 consider the hazard presented by the previously unrecognized north trending fault zone

a scenario study of seismically induced landsliding in seattle using broadband synthetic seismograms abstract we demonstrate the value of utilizing broadband synthetic seismograms to assess regional seismically induced landslide hazard focusing on a case study of an m w 7 0 seattle fault earthquake in seattle washington we computed broadband synthetic seismograms that account for rupture directivity and 3d basin amplification we then adjusted the computed motions on a fine grid for 1d amplifications based on the site response of typical geologic profiles in seattle and used these time series ground motions to trigger shallow landsliding using the newmark method the inclusion of these effects was critical in determining the extent of landsliding triggered we found that for inertially triggered slope failures modeled by the newmark method the ground motions used to simulate landsliding must have broadband frequency content in order to capture the full slope displacement we applied commonly used simpler methods based on ground motion prediction equations for the same scenario and found that they predicted far fewer landslides if only the mean values were used but far more at the maximum range of the uncertainties highlighting the danger of using just the mean values for such methods our results indicate that landsliding triggered by a large seattle fault earthquake will be extensive and potentially devastating causing direct losses and impeding recovery the high impact of landsliding predicted by this simulation shows that this secondary effect of earthquakes should be studied with as much vigor as other earthquake effects online material high resolution maps of relative seismically induced landslide hazard for an m w 7 0 seattle fault earthquake for dry and saturated soil conditions

a laboratory inter comparison of quartz optically stimulated luminescence osl results abstract in this study three sediment samples were used which came from two cave sites situated on the coast of gibraltar gorham s cave and vanguard cave both caves contain silts sands and breccia deposits from the last interglacial through to the post glacial period from which beach sands were sampled for dating the three sediment sample cores were each divided into two sub samples which were independently measured at mcmaster university and oxford university using quartz osl similar sample preparation and measurement procedures were used at both laboratories but different measurement equipment was employed in each it was therefore hoped to identify any factors that may result in systematic differences between laboratories the data showed very good agreement in results when a narrow wavelength band was used for stimulation from either an argon ion laser 514 5 nm or a filtered halogen lamp 514 17 nm this indicates that slight differences in factors such as laboratory lighting measurement time additive dose levels detection filters stimulation source and power did not produce differences in results however when a wide wavelength band from the halogen lamp was used for stimulation 440 560 nm significantly different results were obtained suggesting care needs to be taken with the waveband used

earthquakes generated from bedding plane parallel reverse faults above an active wedge thrust seattle fault zone a key question in earthquake hazard analysis is whether individual faults within fault zones represent independent seismic sources for the seattle fault zone an upper plate structure within the cascadia convergent margin evaluating seismic hazard requires understanding how north side up bedding plane reverse faults which generate late holocene fault scarps interact with the north vergent master ramp thrust and overlying backthrust of the fault zone a regional uplift at a d 900 930 involved an earthquake that nucleated at depth and included slip on both the master ramp thrust and the backthrust this earthquake also included slip on some of the 6 km deep north side up bedding plane reverse faults at locales where the north side up reverse faults intersect the puget sound coast an earthquake a few centuries earlier than the a d 900 930 regional uplift only uplifted areas within hundreds of meters north of the reverse faults we infer that the bedding plane reverse faults are seismogenic because shore platforms near the reverse faults have been abruptly uplifted during earthquakes when other shorelines in the seattle fault zone were unaffected faults of the seattle fault zone therefore can both produce regional uplift earthquakes with or without surface displacement on the reverse faults and produce earthquakes that rupture the bedding plane reverse faults causing fault scarps and uplift localized to hundreds of meters north of these faults this latter type of earthquake has occurred at least twice and perhaps three times in the late holocene and all these earthquakes preceded the regional coseismic uplift of a d 900 930 to account for the paleoseismic observations we propose that the seattle fault zone is a wedge thrust with the leading edge being a fault bend wedge thrust fold the active axial surface of the wedge thrust fold is pinned at the tip of the wedge and a steeply north dipping sequence of tertiary sediment forms the south limb of the wedge thrust fold some of these steeply north dipping bedding plane surfaces are seismogenic reverse faults that produce scarps earthquakes on the wedge thrust produce the regional coseismic uplift events and earthquakes within the faultbend fold cause the local uplift earthquakes thus bedding plane faults can rupture during earthquakes when the wedge thrust does not rupture but instead continues to accumulate seismic energy

mineralogical analysis of the ac h 6 haulani quadrangle of the dwarf planet ceres abstract ac h 6 haulani is one of five quadrangles that cover the equatorial region of the dwarf planet ceres this quadrangle is notable for the broad spectrally distinct ejecta that originate from the crater haulani which gives the name to the quadrangle these ejecta exhibit one of the most negative bluest visible to near infrared spectral slope observed across the entire body and have distinct color properties as seen in multispectral composite images besides haulani here we investigate a broader area that includes other surface features of interest with an emphasis on mineralogy as inferred from data obtained by dawn s visible infrared mapping spectrometer vir combined with multispectral image products from the dawn framing camera fc so as to enable a clear correlation with specific geologic features our analysis shows that crater haulani stands out compared to other surface features of the quadrangle albedo maps obtained in the near infrared range at 1 2 m and 1 9 m reveal that the floor and ejecta of haulani are indeed a patchwork of bright and dark material units visible to near infrared spectral slopes display negative values in crater haulani s floor and ejecta highlighting bluish younger terrains diagnostic spectral features centered at 2 7 m and 3 1 m respectively indicate a substantial decrease in the abundances of magnesium bearing phyllosilicates and ammoniated phyllosilicates in crater haulani s floor and bright ejecta similar but less prominent spectral behavior is observed in other geologic features of this quadrangle while the general trend in quadrangle ac h 6 for these two mineral species is to increase from the northwest to the southeast however it is worth noting that the correlation between the 2 7 m and 3 1 m spectral parameters is generally strong in the haulani crater s area but much weaker elsewhere which indicates a variable degree of mixing between these two major mineral phases in moving away from the crater finally the region of crater haulani displays a distinct thermal signature and a local enhancement in calcium and possibly sodium carbonate minerals which is hardly found in the rest of the quadrangle and is likely the result of intense hydrothermal processes following the impact event these evidences all together confirm the young age of crater haulani as they have not been erased or made elusive by space weathering processes

vesta surface thermal properties map the first ever regional thermal properties map of vesta has been derived from the temperatures retrieved by infrared data by the mission dawn the low average value of thermal inertia 30 10 j m 2 s 0 5 k 1 indicates a surface covered by a fine regolith a range of thermal inertia values suggesting terrains with different physical properties has been determined the lower thermal inertia of the regions north of the equator suggests that they are covered by an older more processed surface a few specific areas have higher than average thermal inertia values indicative of a more compact material the highest thermal inertia value has been determined on the marcia crater known for its pitted terrain and the presence of hydroxyl in the ejecta our results suggest that this type of terrain can be the result of soil compaction following the degassing of a local subsurface reservoir of volatiles

basin shear wave velocities beneath seattle washington from noise correlation rayleigh waves tomography with short period rayleigh waves extracted using noise interferometry can refine s wave velocity v s models in urban areas with dense arrays of short period and broadband instruments we apply this technique to the seattle area to develop a new shallow v s model for use in seismic hazard assessment continuous data from the seismic hazards in puget sound ships array and local broadband stations have interstation distances of 90 km or less this spacing allows us to extract rayleigh waves with periods between 2 and 10 s that are sensitive to shallow basin structure this new v s model for the seattle basin is constructed using direct observations rather than using p wave velocity v p observations and a v p v s ratio as all previous 3d models at this scale have been constructed our results reveal greater detail in the upper 3 5 km than previous models earthquake simulations calculated using our new model better predict peak ground velocities pgv at periods between 1 and 2 s for two local earthquakes than the previous model used to calculate seattle s seismic hazard map frankel et al 2007 we collected data from two local earthquakes and ran finite difference simulations using our new velocity model as well as the previous velocity model used in development of the seattle seismic hazard maps to assess how well our model predicts ground motions relative to the previous model with a recent deployment of netquakes strong motion stations by the pacific northwest seismic network pnsn and the u s geological survey we are now able to make more comprehensive assessments of the predictions for recent events

location structure and seismicity of the seattle fault zone washington evidence from aeromagnetic anomalies geologic mapping and seismic reflection data a high resolution aeromagnetic survey of the puget lowland shows details of the seattle fault zone an active but largely concealed east trending zone of reverse faulting at the southern margin of the seattle basin three elongate east trending magnetic anomalies are associated with north dipping tertiary strata exposed in the hanging wall the magnetic anomalies indicate where these strata continue beneath glacial deposits the northernmost anomaly a narrow elongate magnetic high precisely correlates with magnetic miocene volcanic conglomerate the middle anomaly a broad magnetic low correlates with thick nonmagnetic eocene and oligocene marine and fluvial strata the southern anomaly a broad complex magnetic high correlates with eocene volcanic and sedimentary rocks this tripartite package of anomalies is especially clear over bainbridge island west of seattle and over the region east of lake washington although attenuated in the intervening region the pattern can be correlated with the mapped strike of beds following a northwest striking anticline beneath seattle the aeromagnetic and geologic data define three main strands of the seattle fault zone identified in marine seismic reflection profiles to be subparallel to mapped bedrock trends over a distance of 50 km the locus of faulting coincides with a diffuse zone of shallow crustal seismicity and the region of uplift produced by the m 7 seattle earthquake of a d 900 930

martian high latitude permafrost depth and surface cover thermal inertia distributions 1 martian high latitudes have thermal properties consistent with an extensive high thermal inertia permafrost layer near the surface surface cover thermal inertias and permafrost depths at martian high latitudes 50 80 n s are derived from thermal emission spectrometer tes data and compared with previously published water ice depths determined from the mars odyssey neutron spectrometer mons the depth to the permafrost layer is correlated with surface cover thermal inertia albedo and latitude in general agreement with predicted trends of water ice stability comparison of permafrost depths with water ice rich layer depths derived from mons data displays good qualitative agreement although a divergence is present at greater burial depths this disparity may be due to the presence of hydrated minerals at shallow depths or a lower than expected permafrost thermal inertia corresponding with low water ice concentrations at greater depths surface cover thermal inertias are greater in the northern high latitudes than in the south and differences between these and previous results will have significant effects on the predicted depth of martian water ice stability several regions in the northern hemisphere display high surface cover thermal inertia associated with possible receding water ice deposits that are shallow enough to influence diurnal surface temperatures significant lateral and vertical heterogeneity in water ice distributions are present and the martian regolith is likely more complicated than can be described by simple two layered models and a single mode of water ice emplacement

interpretation of the seattle uplift washington as a passive roof duplex we interpret seismic lines and a wide variety of other geological and geophysical data to suggest that the seattle uplift is a passive roof duplex a passive roof duplex is bounded top and bottom by thrust faults with opposite senses of vergence that form a triangle zone at the leading edge of the advancing thrust sheet in passive roof duplexes the roof thrust slips only when the floor thrust ruptures the seattle fault is a south dipping reverse fault forming the leading edge of the seattle uplift a 40 km wide fold and thrust belt the recently discovered north dipping tacoma reverse fault is interpreted as a back thrust on the trailing edge of the belt making the belt doubly vergent floor thrusts in the seattle and tacoma fault zones imaged as discontinuous reflections are interpreted as blind faults that flatten updip into bedding plane thrusts shallow monoclines in both the seattle and tacoma basins are interpreted to overlie the leading edges of thrust bounded wedge tips advancing into the basins across the seattle uplift seismic lines image several shallow short wavelength folds exhibiting quaternary or late quaternary growth from reflector truncation several north dipping thrust faults splay thrusts are inferred to core these shallow folds and to splay upward from a shallow roof thrust some of these shallow splay thrusts ruptured to the surface in the late holocene ages from offset soils in trenches across the fault scarps and from abruptly raised shorelines indicate that the splay roof and floor thrusts of the seattle and tacoma faults ruptured about 1100 years ago manuscript received 9 september 2003

subsurface geometry and evolution of the seattle fault zone and the seattle basin washington the seattle fault a large seismically active east west striking fault zone under seattle is the best studied fault within the tectonically active puget lowland in western washington yet its subsurface geometry and evolution are not well constrained we combine several analysis and modeling approaches to study the fault geometry and evolution including depth converted deep seismic reflection images p wave velocity field gravity data elastic modeling of shoreline uplift from a late holocene earthquake and kinematic fault restoration we propose that the seattle thrust or reverse fault is accompanied by a shallow antithetic reverse fault that emerges south of the main fault the wedge enclosed by the two faults is subject to an enhanced uplift as indicated by the boxcar shape of the shoreline uplift from the last major earthquake on the fault zone the seattle basin is interpreted as a flexural basin at the footwall of the seattle fault zone basin stratigraphy and the regional tectonic history lead us to suggest that the seattle fault zone initiated as a reverse fault during the middle miocene concurrently with changes in the regional stress field to absorb some of the north south shortening of the cascadia forearc kingston arch 30 km north of the seattle fault zone is interpreted as a more recent disruption arising within the basin probably due to the development of a blind reverse fault manuscript received 23 august 2001

quantifying offshore fore arc deformation and splay fault slip using drowned pleistocene shorelines arauco bay chile most of the deformation associated with the seismic cycle in subduction zones occurs offshore and has been therefore difficult to quantify with direct observations at millennial time scales here we study millennial deformation associated with an active splay fault system in the arauco bay area off south central chile we describe hitherto unrecognized drowned shorelines using high resolution multibeam bathymetry geomorphic sedimentologic and paleontologic observations and quantify uplift rates using a landscape evolution model along a margin normal profile uplift rates are 1 3 m ka near the edge of the continental shelf 1 5 m ka at the emerged santa maria island 0 1 m ka at the center of the arauco bay and 0 3 m ka in the mainland the bathymetry images a complex pattern of folds and faults representing the surface expression of the crustal scale santa maria splay fault system we modeled surface deformation using two different structural scenarios deep reaching normal faults and deep reaching reverse faults with shallow extensional structures our preferred model comprises a blind reverse fault extending from 3 km depth down to the plate interface at 16 km that slips at a rate between 3 0 and 3 7 m ka if all the splay fault slip occurs during every great megathrust earthquake with a recurrence of 150 200 years the fault would slip 0 5 m per event equivalent to a magnitude 6 4 earthquake however if the splay fault slips only with a megathrust earthquake every 1000 years the fault would slip 3 7 m per event equivalent to a magnitude 7 5 earthquake

seismicity and geometry of a 110 km long blind thrust fault 2 synthesis of the 1982 1985 california earthquake sequence during 1982 1985 three 5 4 mw 6 5 earthquakes migrated 65 km along the north half of a string of quaternary folds at the east front of the california coast ranges there is no surface fault associated with these earthquakes but the fold chain oriented parallel to the san andreas fault 30 km to the west takes up contraction normal to the san andreas fault identification of active blind thrust faults is hindered by the absence of a fault trace but may be revealed by the presence of growing folds at the surface and by earthquakes at depth because of excellent seismic geodetic and geologic data this earthquake sequence illuminates the geometry of the blind faults and enables us to probe their mechanics we relocate seismicity and compute focal mechanisms in a three dimensional velocity space and model the vertical deformation associated with the 1983 m 6 5 coalinga earthquake the aftershock zones abut at echelon offsets in the fold axes and the mainshocks display reverse slip perpendicular to the axes suggesting that the folds conceal a contiguous segmented thrust fault background seismicity concentrates at bends and breaks in the fold chain sites that may correspond to tears and ramps in the thrust fault at depth seismic reflection profiles reveal thrust and reverse faults dipping toward the san andreas fault at depths of 5 10 km with several kilometers of cumulative slip and high angle reverse faults in the anticlines with several hundred meters cumulative slip coseismic fold uplift accompanied the coalinga and kettleman hills north dome earthquakes suggesting that fold growth is episodic and coupled closely to repeated earthquakes on the underlying thrusts the north half of the fold chain has been the site of several 6 m 6 5 earthquakes since 1885 thus kettleman hills middle dome the next fold segment to the south has an elevated seismic potential the aftershock zones of the three main shocks are diffuse and occupy a region much larger than the site of seismic slip aftershocks occur 5 7 km from the fault regions where on the basis of a boundary element model the shear strain increase caused by the fault slip exceeds 20 ppm equivalent to about 0 7 mpa we argue that the broad aftershock zone is a product of high sustained off fault stress caused by repeated displacement on faults that do not cut the earth s surface the fault tip stresses lead to the formation of secondary faults which can become sites of aftershocks and postseismic creep

seismic reflection images beneath puget sound western washington state the puget lowland thrust sheet hypothesis seismic reflection data show that the densely populated puget lowland of western washington state is underlain by subhorizontal paleogene and neogene sedimentary rocks deformed by west and northwest trending faults and folds from south to north beneath the lowland features seen on the seismic data include the horizontally stratified 3 5 km thick tacoma sedimentary basin the seattle uplift with south dipping 20 strata on its south flank and steeply 50 to 90 north dipping strata and the west trending seattle fault on its north flank the 7 5 km thick northward thinning seattle sedimentary basin the antiformal kingston arch and the northwest trending transpressional southern whidbey island fault zone swif interpreting the uplifts as fault bend and fault propagation folds leads to the hypothesis that the puget lowland lies on a north directed thrust sheet the base of the thrust sheet may lie at 14 to 20 km depth within or at the base of a thick block of basaltic crescent formation its edges may be right lateral strike slip faults along the base of the cascade range on the east and the olympic mountains on the west our model suggests that the seattle fault has a long term slip rate of about 0 25 mm year and is large enough to generate a m7 6 to 7 7 earthquake

high resolution thermal inertia derived from the thermal emission imaging system themis thermal model and applications 1 thermal inertia values at 100 m per pixel are determined using nighttime temperature data from the thermal emission imaging system themis on the mars odyssey spacecraft producing the highest resolution thermal inertia data set to date themis thermal inertia values have an overall accuracy of 20 a precision of 10 15 and are consistent with both thermal emission spectrometer orbital and miniature thermal emission spectrometer surface thermal inertia values this data set enables the improved quantification of fine scale surface details observed in high resolution visible images in the tharsis region surface textures and crater rims observed in visible images have no corresponding variation in the themis thermal inertia images indicating that the dust mantle is pervasive at themis scales and is a minimum of a few centimeters and up to 1 2 m thick the thermal inertia of bed form material indicates particle diameters expected for aeolian sediments and these materials are likely currently saltating variations in the thermal inertia within interior layered deposits in hebes chasma can be distinguished and the thermal inertia is too low to be consistent with bedrock or a lava flow thus a secondary emplacement of volcanic material or a volcanic ash deposit is a more likely method of formation higher resolution themis thermal inertia enables the identification of exposed bedrock on the martian surface in nili patera and ares vallis bedrock material corresponds to distinct compositional and morphologic surfaces indicating that a specific unit is exposed and is likely currently being kept free of unconsolidated material by aeolian processes

late holocene sea level record in a core from the puget lowland washington abstract diatoms and lithological facies of an 8 45 m core collected from shine swamp 47 52 20 n lat 122 41 45 w long about 2 m above the mean tide level in the northern puget lowland reveal a rise in relative sea level during the past 6000 yr a layer of fresh water peat at a depth of 6 6 6 3 m ca 7000 5000 yr b p indicates a low stand of the sea in early and middle holocene time about 5000 yr ago the rise in relative sea level resulted in accumulation of subtidal or lower intertidal clayey gyttja and gyttja which contain mainly marine and brackish water diatoms 80 95 by about 3500 yr b p the basin had shoaled to upper intertidal levels and peat began to accumulate again while the sea continued its relative rise during the period of this continuous peat growth several alterations in fresh water and marine brackish water diatom assemblages took place indicating slight differences in the contemporaneous sea level rise and vertical peat growth

a late holocene marine terrace on the kidnappers coast north island new zealand some implications for shore platform development processes and uplift mechanism abstract a marine terrace up to 6 m above present mean sea level is preserved along 15 km of the kidnappers coast hawke s bay north island new zealand radiocarbon dates for 10 shell samples collected from intertidal marine deposits overlying an uplifted shore platform have a total age range of 590 yr from 2280 50 to 2750 70 yr b p sample age decreases landward suggesting a small relative sea level rise probably as a result of tectonic subsidence prior to uplift rates of contemporary shore platform formation preclude the preservation of a marine terrace subjected to constant aseismic uplift preservation of a subhorizontal uplifted shore platform mantled by intertidal marine deposits with in situ fauna is best explained by abrupt coseismic uplift 2300 yr b p and preceded by tectonic subsidence the presence of a single marine terrace does not permit the calculation of past earthquake magnitude or recurrence but the nne tilt of the 2300 yr old marine terrace indicates continued growth of the north trending late pleistocene kidnappers anticline

permanent upper plate deformation in western myanmar during the great 1762 earthquake implications for neotectonic behavior of the northern sunda megathrust the 1762 arakan earthquake resulted from rupture of the northern sunda megathrust and is one of those rare preinstrumental earthquakes for which early historical accounts document ground deformations in order to obtain more comprehensive and detailed measurements of coseismic uplift we conducted comprehensive field investigations and geochronological analyses of marine terraces on the two largest islands in western myanmar we confirm 3 4 m of coseismic coastal emergence along southwestern cheduba island diminishing northeastward to less than 1 m farther northeast uplift associated with the earthquake ranges from slightly more than 1 m to 5 6 m along the western coast of ramree island but is insignificant along the island s eastern coast this double hump pattern of uplift coincides with the long term anticlinal growth of these two islands thus we propose that the 1762 earthquake resulted from slip on splay faults under the islands in addition to rupture of the megathrust elastic modeling implies that fault slip during the 1762 earthquake ranges from about 9 to 16 m beneath the islands and corresponds to a magnitude of m w 8 5 if the rupture length of the megathrust is 500 km the island s uplift histories suggest recurrence intervals of such events of about 500 700 years additional detailed paleoseismological studies would add significant additional detail to the history of large earthquakes in this region

a holocene sedimentary record of tectonically influenced reduced channel mobility skokomish river delta washington state usa abstract at the skokomish river delta in washington state s puget lowland coseismic uplift and tilting trapped the river against a valley wall resulting in little to no channel migration for the last 1000 years the most recent earthquake occurred before ad 780 990 based on stratigraphic evidence such as sand blows and abrupt facies changes since the hypothesized tilting a 5 km long section of the river has not migrated laterally or avulsed resulting in reduced migration and a muddy intertidal flat that is 2 km wider in the east than on the west side of annas bay a ridge running perpendicular to the river may also have restricted channel mobility the ridge may be either the surface expression of a blind thrust fault or a relict uplifted and tilted shoreline the uplift and tilting of the delta can be ascribed to any of three nearby active fault zones of which the most likely based on the orientation of deformation is the saddle mountain fault zone which produced a surface rupture 1000 1300 years ago the delta has experienced submergence since the earthquake a forest that colonized an uplifted part of the delta about 800 1200 years ago was later submerged by at least 1 6 m and is now a brackish water marsh

bright carbonate surfaces on ceres as remnants of salt rich water fountains abstract vinalia and cerealia faculae are bright and salt rich localized areas in occator crater on ceres the predominance of the near infrared signature of sodium carbonate on these surfaces suggests their original material was a brine here we analyze dawn framing camera s images and characterize the surfaces as composed of a central structure either a possible depression vinalia or a central dome cerealia and a discontinuous mantling we consider three materials enabling the ascent and formation of the faculae ice ascent with sublimation and carbonate particle lofting pure gas emission entraining carbonate particles and brine extrusion we find that a mechanism explaining the entire range of morphologies topographies as well as the common composition of the deposits is brine fountaining this process consists of briny liquid extrusion followed by flash freezing of carbonate and ice particles particle fallback and sublimation subsequent increase in briny liquid viscosity leads to doming dawn observations did not detect currently active water plumes indicating the frequency of such extrusions is longer than years

origin and evolution of the seattle fault and seattle basin washington analysis of seismic reflection data reveals that the seattle basin washington is markedly asymmetric and consists of 9 10 km of eocene and younger deposits the basin began as a discrete geologic element in the late eocene 40 ma the result of a reorganization in regional fault geometry and kinematics in this reorganization dextral offset on the puget fault south east of seattle stepped eastward and the seattle fault began as a restraining transfer zone north vergent reverse or thrust faulting on the seattle fault forced flexural subsidence in the seattle basin to the north offset on the seattle fault and subsidence of the seattle basin have continued to the present

structure of the eastern seattle fault zone washington state new insights from seismic reflection data we identify and characterize the active seattle fault zone sfz east of lake washington with newly acquired seismic reflection data our results focus on structures observed in the upper 1 km below the cities of bellevue sammamish newcastle and fall city washington the sfz appears as a broad zone of faulting and folding at the southern boundary of the seattle basin and north edge of the seattle uplift we interpret the seattle fault as a thrust fault that accommodates north south shortening by forming a fault propagation fold with a forelimb breakthrough the blind tip of the main fault forms a synclinal growth fold deformation front that extends at least 8 km east of vasa park west side of lake sammamish and defines the south edge of the seattle basin south of the deformation front is the forelimb breakthrough fault which was exposed in a trench at vasa park the newcastle hills anticline a broad anticline forming the north part of the seattle uplift east of lake washington is interpreted to lie between the main blind strand of the seattle fault and a backthrust our profiles on the northern limb of this anticline consistently image north dipping strata a structural model for the sfz east of lake washington is consistent with about 8 km of slip on the upper part of the seattle fault but the amount of motion is only loosely constrained

coseismic folding earthquake recurrence and the 1987 source mechanism at whittier narrows los angeles basin california static deformation associated with the october 1 1987 whittier narrows california m 6 0 earthquake was detected by geodetic elevation changes the earthquake uplifted a 1 5 km high quaternary fold the santa monica mountains anticlinorium by 50 mm but caused no fault rupture at the ground surface this suggests that folding and faulting of the los angeles basin sediments are coincident and continuing after correction for surveying errors and nontectonic subsidence we model the 214 geodetic observations with a simple dislocation in an elastic half space a thrust fault with reverse slip of 1 1 0 3 m and dipping 30 4 n with an upper edge at a depth of 12 1 km and a lower edge at 17 1 km fits the geodetic data best and is consistent with the main shock hypocenter fault plane solution and initial aftershock distribution the upper limit on the static stress drop is 17 5 5 0 mpa 175 50 bar the lower limit on the geodetic moment is 1 0 0 2 1025 dyne cm in accord with seismic estimates indicating that most of the slip took place during seismic rupture if earthquakes of m 6 characterize the blind thrust fault on which the earthquake occurred we estimate a 200 year repeat time at whittier narrows and a 5 18 year rate of earthquake occurrence within a 150 km long band in the northern los angeles basin and santa monica bay to the west the 25 year rate of historical occurrence since 1860 is less than this prediction the deficit in moment release implies that either vigorous aseismic slip or infrequent larger earthquakes occur here

coseismic and pre seismic subsidence associated with great earthquakes in alaska abstract alternating beds of peat and mud in sediment sequences on the south central alaskan coast record coseismic and inter seismic relative land and sea level movements caused by repeated great earthquakes on the alaska aleutian subduction zone during the ad 1964 mw 9 2 earthquake tidal marshes and wetlands around upper cook inlet experienced up to 2 m of subsidence burying peat forming communities with intertidal mud here we use quantitative analyses of fossil diatoms within peat mud couplets to reconstruct land sea level changes for the 1964 and five earlier great earthquakes during the past 3300 years in contrast to geodetic observations that are limited to the present post seismic phase we quantify varying spatial patterns of uplift and subsidence through complete earthquake cycles relative land uplift characterises most of the inter seismic phase of each cycle at our sites whereas each great earthquake was preceded by a short period of pre seismic relative land subsidence

a possible brine reservoir beneath occator crater thermal and compositional evolution and formation of the cerealia dome and vinalia faculae abstract the dawn spacecraft has imaged several putative cryovolcanic features on ceres and several lines of evidence point to past cryovolcanic activity at occator crater it is therefore possible that cryovolcanism played a key role in delivering sodium carbonate and chloride enriched brines to ceres surface in recent geological times the detection of a 200 km 200 km negative bouguer anomaly beneath occator suggests the presence of a low density region beneath the crater if this region is a residual partially crystallized cryomagma chamber excess pressures caused by its gradual freezing or stresses produced by the occator forming impact could have facilitated the delivery of cryolavas to the surface in the geologically recent past here the progressive solidification of a cryomagma chamber beneath occator and implications for the delivery of cryolavas to the surface has been explored models for the behavior of cryolavas at ceres surface and for the formation of the cerealia dome and vinalia faculae are also presented minimal crystallization of a subsurface fluid reservoir located at the crust mantle boundary could have driven cryolavas enriched in chloride salts and nh3 to ceres surface however cryolavas enriched in sodium carbonates would have had to have existed at shallower levels in the crust in order to be delivered to the surface via pressure driven ascent depending on the size of the reservoir cryolavas could have been driven to ceres surface for tens to hundreds of millions of years after cooling of the cryomagma chamber commenced the mineralogy at occator is suggestive of subsurface cryomagma reservoirs enriched in sodium carbonate and chloride salts aqueous solutions enriched in chloride salts and or ammonia would have arrived at the surface at warm enough temperatures to erupt if transported in propagating fractures that traveled at least 10 5 m s additionally if the cerealia dome was formed from viscous cryolava extrusions bulk kinematic lava viscosities may have been between 106 108 m2 s at the onset of relaxation plausible relaxation times to form the dome which are linked to bulk cryolava rheology are found to have ranged from 2 5 to 273 days moreover the low volatile content necessary to drive explosive eruptions on ceres supports the possibility that cerealia and vinalia faculae were emplaced as a consequence of ballistic eruptions the enigmatic geology of occator crater is consistent with a diversity of exchange processes operating on ceres in the geologically recent past further the processes that have occurred at occator could shed light on the changing geology associated with a relic ocean world future studies of occator and ceres should be undertaken with these results in mind

a tsunami about 1000 years ago in puget sound washington water surged from puget sound sometime between 1000 and 1100 years ago overrunning tidal marshes and mantling them with centimeters of sand one overrun site is 10 kilometers northwest of downtown seattle another is on whidbey island some 30 kilometers farther north neither site has been widely mantled with sand at any other time in the past 2000 years deposition of the sand coincided to the year or less with abrupt probably tectonic subsidence at the seattle site and with landsliding into nearby lake washington these findings show that a tsunami was generated in puget sound and they tend to confirm that a large shallow earthquake occurred in the seattle area about 1000 years ago

mgs tes thermal inertia study of the arsia mons caldera 1 temperatures of the arsia mons caldera floor and two nearby control areas were obtained by the mars global surveyor mgs thermal emission spectrometer tes these observations revealed that the arsia mons caldera floor exhibits thermal behavior different from the surrounding tharsis region when compared with thermal models our technique compares modeled and observed data to determine best fit values of thermal inertia layer depth and albedo best fit modeled values are accurate in the two control regions but those in the arsia mons caldera are consistently either up to 15 k warmer than afternoon observations or have albedo values that are more than two standard deviations higher than the observed mean models of both homogeneous and layered such as dust over bedrock cases were compared with layered cases indicating a surface layer at least thick enough to insulate itself from diurnal effects of an underlying substrate material because best fit models of the caldera floor poorly match observations it is likely that the caldera floor experiences some physical process not incorporated into our thermal model even on mars arsia mons is an extreme environment where co2 condenses upon the caldera floor every night diurnal temperatures range each day by a factor of nearly 2 and annual average atmospheric pressure is only around one millibar here we explore several possibilities that may explain the poor modeled fits to caldera floor and conclude that temperature dependent thermal conductivity may cause thermal inertia to vary diurnally and this effect may be exaggerated by presence of water ice clouds which occur frequently above arsia mons

vented sediments and tsunami deposits in the puget lowland washington differentiating sedimentary processes the sandy deposits produced by tsunamis and liquefaction share many sedimentary features and distinctions between the two are important in seismically active coastal zones both types of deposits are present in the wetlands bordering puget sound where one or more earthquakes about 1100 years ago caused both tsunami flooding and sediment venting this co occurrence allows an examination of the resulting deposits and a comparison with tsunami and liquefaction features of modern events vented sediments occur at four of five wetland field localities and tsunami deposits at two in comparison with tsunami deposits vented sediments in this study and from other studies tend to be thicker although they can be thin vented sediments also have more variable thickness at both outcrop and map scale are associated with injected dykes and contain clasts derived from underlying deposits further vented sediments tend to contain a greater variety of sedimentary structures and these structures vary laterally over metres tsunami deposits compared with vented sediments are commonly thinner fine and thin landward more consistently have more uniform thickness on outcrop and map scales and have the potential of containing coarser clasts up to boulders for both tsunami deposits and vented sediments the availability and grain size of source material condition the characteristics of the deposit in the cases presented in this paper both foraminifera and diatom assemblages within tsunami deposits and vented sediments consisted of brackish and marine species and no distinction between processes could be made based on microfossils in summary this study indicates a need for more careful analysis and mapping of coastal sediments associated with earthquakes to avoid misidentification of processes and misevaluation of hazards

late quaternary uplift rate inferred from marine terraces shimokita peninsula northeastern japan a preliminary investigation of the buried shoreline angle after estimating tectonic uplift rates along the northern part of the northeast japan forearc the overriding plate in the northeast japan subduction zone by mapping the elevation of the inner edges of marine terrace surfaces we refined this estimate through elevation measurements of the buried shoreline angle beneath well dated marine terrace surfaces from which we could derive more accurate paleo sea levels the uplift rate initially inferred from the inner edge of marine terrace t4 correlated with marine isotope stage mis 5e by tephrochronology increases eastward from 0 11 0 22 m ky 1 around the backarc volcanic front to 0 17 0 32 m ky 1 in the forearc on the peninsula of shiriyazaki we refined the uplift rates for t4 on the basis of the shoreline angle elevation from the reconstructed profile of the paleo sea cliff and wave cut platform on a rocky coast and the reconstructed profile of the swash zone sediments and terrace deposits on a sandy coast the refined uplift rates were 0 14 0 25 m ky 1 on the rocky coast and 0 14 0 23 m ky 1 on the sandy coast slightly slower than the rates we inferred from the height of t4 and about one half to three fourths of previously reported rates by extrapolation from the example of the sandy coast the refined uplift rate around the volcanic front was 0 09 0 18 m ky 1 the vertical deformation across the forearc of the shimokita peninsula since mis 5e is possibly associated with regional isostatic uplift of 0 09 0 18 m ky 1 and anticlinal deformation by an offshore fault interpreted from acoustic profiles of 0 05 0 07 m ky 1

predictions of depth to ice on asteroids based on an asynchronous model of temperature impact stirring and ice loss abstract water ice near the surface of main belt asteroids is gradually lost to space a mantle of low thermal conductivity causes large surface temperature amplitudes and thus increased cooling by thermal re radiation lowering temperatures well below the fast rotator limit a computational barrier for modeling this ice loss is the multi scale character of the problem accurate temperatures require many time steps within a solar day but ice retreats slowly over billions of years this barrier is overcome with asynchronous coupling models of temperature ice loss and impact stirring each use their own time steps and are coupled with one another the model is applied to 1 ceres and 7968 elst pizarro on ceres ice can be expected in the top half meter poleward of 60 latitude on both hemispheres even if excursions of the axis tilt took place and even in the presence of impact gardening at the poles ice can be expected within a centimeter of the surface the retreating ice crust leads to emission of water from the surface mainly at the equator the gradually retreating ice supplies a water exosphere less dense than has been observed by the herschel telescope for main belt comet elst pizarro depths to ice depend on the properties of the surface mantle for a dust mantle estimated depths are on the order of a decimeter for a rocky surface the depth at the pole is on the order of one meter hence it could have been activated by a small impact that exposed buried ice

imaging the seattle fault zone with high resolution seismic tomography the seattle fault which trends east west through the greater seattle metropolitan area is a thrust fault that around 1100 years ago produced a major earthquake believed to have had a magnitude greater than 7 we present the first high resolution image of the shallow p wave velocity variation across the fault zone obtained by tomographic inversion of first arrivals recorded on a seismic reflection profile shot through puget sound adjacent to seattle the velocity image shows that above 500 m depth the fault zone extending beneath seattle comprises three distinct fault splays the northernmost of which dips to the south at around 60 the degree of uplift of tertiary rocks within the fault zone suggests that the slip rate along the northernmost splay during the quaternary is 0 5 mm a 1 which is twice the average slip rate of the seattle fault over the last 40 ma

paleogeodetic records of seismic and aseismic subduction from central sumatran microatolls indonesia we utilize coral microatolls in western sumatra to document vertical deformation associated with subduction microatolls are very sensitive to fluctuations in sea level and thus act as natural tide gauges they record not only the magnitude of vertical deformation associated with earthquakes paleoseismic data but also continuously track the long term aseismic deformation that occurs during the intervals between earthquakes paleogeodetic data this paper focuses on the twentieth century paleogeodetic history of the equatorial region our coral paleogeodetic record of the 1935 event reveals a classical example of deformations produced by seismic rupture of a shallow subduction interface the site closest to the trench rose 90 cm whereas sites further east sank by as much as 35 cm our model reproduces these paleogeodetic data with a 2 3 m slip event on the interface 88 to 125 km from the trench axis our coral paleogeodetic data reveal slow submergence during the decades before and after the event in the areas of coseismic emergence likewise interseismic emergence occurred before and after the 1935 event in areas of coseismic submergence among the interesting phenomenon we have discovered in the coral record is evidence of a large aseismic slip or silent event in 1962 27 years after the 1935 event paleogeodetic deformation rates in the decades before after and between the 1935 and 1962 events have varied both temporally and spatially during the 25 years following the 1935 event submergence rates were dramatically greater than in prior decades during the past four decades however rates have been lower than in the preceding decades but are still higher than they were prior to 1935 these paleogeodetic records enable us to model the kinematics of the subduction interface throughout the twentieth century

rupture models for the a d 900 930 seattle fault earthquake from uplifted shorelines a major earthquake on the seattle fault washington ca a d 900 930 was first inferred from uplifted shorelines and tsunami deposits despite follow up geophysical and geological investigations the rupture parameters of the earthquake and the geometry of the fault are uncertain here we estimate the fault geometry slip direction and magnitude of the earthquake by modeling shoreline elevation change the best fitting model geometry is a reverse fault with a shallow roof ramp consisting of at least two back thrusts the best fitting rupture is a sw ne oblique reverse slip with horizontal shortening of 15 m rupture depth of 12 5 km and magnitude mw 7 5

the a d 900 930 seattle fault zone earthquake with a wider coseismic rupture patch and postseismic submergence inferences from new sedimentary evidence stratigraphic evidence for coseismic uplift a tsunami and a sandy debris flow linked to the a d 900 930 seattle fault zone earthquake and subsequent submergence is present at gorst at the terminus of sinclair inlet washington this study indicates that at least 3 m of uplift preceded a tsunami followed by a sandy debris flow though the seattle and tacoma fault zones ruptured within the error of ages of the tsunami deposit model simulations indicate the seattle fault generates an order of magnitude larger tsunami in the vicinity of the field area than the tacoma fault and is the more likely generator of the tsunami simulations indicate amplitude from a seattle fault zone generated wave train was 4 5 m and stratigraphy shows the tsunami left a sandy deposit soft sediment deformation narrows the time window for the debris flow to the hours to months after the tsunami slope failure in unconsolidated glacial sands likely initiated a debris flow that surged at least 2 km down gorst creek valley and left a more than 40 cm thick deposit along the creek and in the wetlands submergence of a thuja plicata western red cedar swamp into the intertidal zone indicates at least 1 5 m of submergence in the last 1100 years this submergence indicates uplift on nearby marine terraces associated with the seattle fault zone was likely higher and the a d 900 930 earthquake was potentially larger than previously recognized

thermal stability of ice on ceres with rough topography the dwarf planet ceres may have an ice rich crust and subsurface ice exposed by impacts or endogenic activity would be subject to sublimation we model surface and subsurface temperatures on ceres to assess lifetimes of water ice and other volatiles topographic shadowing allows a small but non negligible fraction 0 4 of ceres surface to be perennially below the 110 k criterion for 1 gyr of stability these areas are found above 60 latitude other molecules ch3oh nh3 so2 co2 may be cold trapped in smaller abundances a model for the transport gravitational escape and photoionization of h2o molecules suggests net accumulation in the cold traps buried ice is stable within a meter for 1 gyr at latitudes higher than 50 an illuminated polar cap of water ice would be stable within a few degrees of the poles only if it maintained a high albedo 0 5 at present obliquity if the obliquity exceeded 5 in the geologically recent past then a putative polar cap would have been erased at latitudes 0 30 ice is stable under solar illumination only briefly 10 100 yr unless it has high albedo and thermal inertia in which case lifetimes of 104 yr are possible finally a small hemispheric asymmetry exists due to the timing of ceres perihelion passage which would lead to a detectable enhancement of ice in the northern hemisphere if the orbital elements vary slowly relative to the ice accumulation rate our model results are potentially testable during the dawn science mission

abrupt uplift within the past 1700 years at southern puget sound washington shorelines rose as much as 7 meters along southern puget sound and hood canal between 500 and 1700 years ago evidence for this uplift consists of elevated wave cut shore platforms near seattle and emerged peat covered tidal flats as much as 60 kilometers to the southwest the uplift was too rapid for waves to leave intermediate shorelines on even the best preserved platform the tidal flats also emerged abruptly they changed into freshwater swamps and meadows without first becoming tidal marshes where uplift was greatest it adjoined an inferred fault that crosses puget sound at seattle and it probably accompanied reverse slip on that fault 1000 to 1100 years ago the uplift and probable fault slip show that the crust of the north america plate contains potential sources of damaging earthquakes in the puget sound region

crustal structure and relocated earthquakes in the puget lowland washington from high resolution seismic tomography 1 the availability of regional earthquake data from the pacific northwest seismograph network pnsn together with active source data from the seismic hazards investigation in puget sound ships seismic experiments has allowed us to construct a new high resolution 3 d p wave velocity model of the crust to a depth of about 30 km in the central puget lowland in our method earthquake hypocenters and velocity model are jointly coupled in a fully nonlinear tomographic inversion active source data constrain the upper 10 15 km of the model and earthquakes constrain the deepest portion of the model a number of sedimentary basins are imaged including the previously unrecognized muckleshoot basin and the previously incompletely defined possession and sequim basins various features of the shallow crust are imaged in detail and their structural transitions to the mid and lower crust are revealed these include the tacoma basin and fault zone the seattle basin and fault zone the seattle and port ludlow velocity highs the port townsend basin the kingston arch and the crescent basement which is arched beneath the lowland from its surface exposure in the eastern olympics strong lateral velocity gradients consistent with the existence of previously inferred faults are observed bounding the southern port townsend basin the western edge of the seattle basin beneath dabob bay and portions of the port ludlow velocity high and the tacoma basin significant velocity gradients are not observed across the southern whidbey island fault the lofall fault or along most of the inferred location of the hood canal fault using improved earthquake locations resulting from our inversion we determined focal mechanisms for a number of the best recorded earthquakes in the data set revealing a complex pattern of deformation dominated by general arc parallel regional tectonic compression most earthquakes occur in the basement rocks inferred to be the lower tertiary crescent formation the sedimentary basins and the eastern part of the olympic subduction complex are largely devoid of earthquakes clear association of hypocenters and focal mechanisms with previously mapped or proposed faults is difficult however seismicity structure and focal mechanisms associated with the seattle fault zone suggest a possible high angle mode of deformation with the north side up we suggest that this deformation may be driven by isostatic readjustment of the seattle basin

evidence for earthquake induced subsidence about 1100 yr ago in coastal marshes of southern puget sound washington buried forest and high marsh soils indicate abrupt changes in relative sea level at four coastal localities in southern puget sound at little skookum inlet and red salmon creek douglas fir stumps in growth position are buried by salt marsh peat at localities along mcallister creek and the nisqually river high marsh soils are buried by tidal flat mud localized liquefaction coincided with submergence of the high marsh soil at mcallister creek dramatic changes in seed and diatom assemblages across these contacts confirm rapid submergence at little skookum inlet and red salmon creek salt marsh peat immediately above a buried forest soil contains diatoms indicative of low marsh and tidal flat environments at mcallister creek and nisqually river low marsh and tidal flat diatoms are abundant in laminated mud directly over high marsh peat inferences from modern analogs indicate at least 1 m of subsidence at each site and possibly up to 3 m at skookum inlet abrupt burial of lowland soils in southern puget sound is best explained by coseismic subsidence some of the submergence may be the result of coseismic compaction and postearthquake settlement widespread buried soils large amounts of subsidence coeval submergence across a wide area and ground shaking at the time of subsidence all point to a large earthquake between 1150 and 1010 cal yr b p in southern puget sound as the most likely cause of subsidence

ceres predictions for near surface water ice stability and implications for plume generating processes this paper will constrain the possible sources and processes for the formation of recently observed h2o vapor plumes above the surface of the dwarf planet ceres two hypotheses have been proposed 1 cryovolcanism where the water source is the mantle and the heating source is still unknown or 2 comet like sublimation where near surface water ice is vaporized by seasonally increasing solar insolation we test hypothesis 2 comet like near surface sublimation by using a thermal model to examine the stability of water ice in the near surface for a reasonable range of physical parameters thermal inertia surface roughness and slopes we find that water ice is only stable at latitudes higher than 40 60 these results indicate that either a the physical properties of ceres are unlike our expectations or b an alternative to comet like sublimation such as the cryovolcanism hypothesis must be invoked

the geology of hotei regio titan correlation of cassini vims and radar abstract joint cassini vims and radar sar data of 700 km wide hotei regio reveal a rich collection of geological features that correlate between the two sets of images the degree of correlation is greater than anywhere else seen on titan central to hotei regio is a basin filled with cryovolcanic flows that are anomalously bright in vims data in particular at 5 m and quite variable in roughness in sar the edges of the flows are dark in sar data and appear to overrun a vims bright substrate sar stereo topography shows the flows to be viscous 100 200 m thick on its southern edge the basin is ringed by higher 1 km mountainous terrain the mountains show mixed texture in sar data some regions are extremely rough exhibit low and spectrally neutral albedo in vims data and may be partly coated with darker hydrocarbons around the southern margin of hotei regio the sar image shows several large dendritic radar bright channels that flow down from the mountainous terrain and terminate in dark blue patches seen in vims images whose infrared color is consistent with enrichment in water ice the patches are in depressions that we interpret to be filled with fluvial deposits eroded and transported by liquid methane in the channels in the vims images the dark blue patches are encased in a latticework of lighter bands that we suggest to demark a set of circumferential and radial fault systems bounding structural depressions conceivably the circular features are tectonic structures that are remnant from an ancient impact structure we suggest that impact generated structures may have simply served as zones of weakness no direct causal connection such as impact induced volcanism is implied we also speculate that two large dark features lying on the northern margin of hotei regio could be calderas in summary the preservation of such a broad suite of vims infrared color variations and the detailed correlation with features in the sar image and sar topography evidence a complex set of geological processes pluvial fluvial tectonic cryovolcanic impact that have likely remained active up to very recent geological time

brucite and carbonate assemblages from altered olivine rich materials on ceres the mineralogy of the dwarf planet ceres has long remained uncertain the infrared spectral features of this planetary body are indicative of minerals derived from the aqueous alteration of olivine rich materials suggesting that ceres is not represented by any known meteorite the dwarf planet ceres is the largest object in the asteroid belt and is generally thought to be a differentiated body composed primarily of silicate materials and water ice1 2 some remotely observed features however indicate that ceres may instead have a composition more similar to that of the most common types of carbonaceous meteorite3 4 5 6 7 in particular ceres has been shown to have a distinct infrared absorption feature centred at a wavelength of 3 06 m that is superimposed on a broader absorption from 2 8 to 3 7 m refs 5 8 which suggests the presence of oh or h2o bearing phases the specific mineral composition of ceres and its relationship to known meteorite mineral assemblages however remains uncertain here we show that the spectral features of ceres can be attributed to the presence of the hydroxide brucite magnesium carbonates and serpentines a mineralogy consistent with the aqueous alteration of olivine rich materials we therefore suggest that the thermal and aqueous alteration history of ceres is different from that recorded by carbonaceous meteorites and that samples from ceres are not represented in existing meteorite collections

exposed water ice discovered near the south pole of mars the mars odyssey thermal emission imaging system themis has discovered water ice exposed near the edge of mars southern perennial polar cap the surface h2o ice was first observed by themis as a region that was cooler than expected for dry soil at that latitude during the summer season diurnal and seasonal temperature trends derived from mars global surveyor thermal emission spectrometer observations indicate that there is h2o ice at the surface viking observations and the few other relevant themis observations indicate that surface h2o ice may be widespread around and under the perennial co2 cap

localized sources of water vapour on the dwarf planet 1 ceres the largest asteroid of the solar system 1 ceres has been thought to have an icy surface here it is observed to be emitting water vapour the presence of hydrated minerals on the surface of ceres the largest body in the solar system s main asteroid belt suggested that there may be water there too now infrared spectra obtained by esa s herschel space observatory provide unambiguous evidence that there is water ice at or near the surface of ceres water vapour is issuing at a rate of at least 1026 molecules per second from sources on ceres localized to mid latitude regions the water evaporation could be due to comet like sublimation or to cryo volcanism in which volcanoes erupt volatiles such as water instead of molten rocks this finding supports models that propose that the icy bodies such as comets may have migrated into the asteroid belt from beyond the notional snowline dividing the early solar system into a dry inner and icy outer regions the snowline conventionally divides solar system objects into dry bodies ranging out to the main asteroid belt and icy bodies beyond the belt models suggest that some of the icy bodies may have migrated into the asteroid belt1 recent observations indicate the presence of water ice on the surface of some asteroids2 3 4 with sublimation5 a potential reason for the dust activity observed on others hydrated minerals have been found6 7 8 on the surface of the largest object in the asteroid belt the dwarf planet 1 ceres which is thought to be differentiated into a silicate core with an icy mantle9 10 11 the presence of water vapour around ceres was suggested by a marginal detection of the photodissociation product of water hydroxyl ref 12 but could not be confirmed by later more sensitive observations13 here we report the detection of water vapour around ceres with at least 1026 molecules being produced per second originating from localized sources that seem to be linked to mid latitude regions on the surface14 15 the water evaporation could be due to comet like sublimation or to cryo volcanism in which volcanoes erupt volatiles such as water instead of molten rocks

the legacy of pleistocene glaciation and the organization of lowland alluvial process domains in the puget sound region article i nfo alluvial rivers of the eastern puget lowland a landscape shaped by scour and fill from the cordilleran ice sheet continue to respond to patterns of deposition and scour by the last glacial age ice sheet 18 000 years after deglaciation topography revealed by valley cross sections created from high resolution lidar digital elevation models shows that rivers are aggrading in valleys eroded by subglacial runoff and degrading in valleys incised by rivers post glaciation slope area analysis of river profiles shows that profile concavity varies systematically between river segments in the two valley contexts concavity indices in mountain headwaters 0 3b b0 9 compare to those of many world rivers 0 2b b1 0 but in the lowlands these indices differ between valleys created by subglacial fluvial erosion 5b b45 and post glacially incised river valleys that grade to base levels set by these relict glacial valleys or by post glacial sea levels 1b b7 dramatic differences in river pattern landforms and dynamics occur in valleys having contrasting aggrading vs degrading and incomplete responses to pleistocene glaciation creating discrete valley scale hetero geneities in fluvial process domains along and between rivers these results point to the importance of valley scale organization of alluvial process domains along and between rivers having profiles remaining in disequilibrium from pleistocene glaciation they also point to the potential usefulness of slope area analysis of longitudinal profiles in distinguishing among different river valley process domains in lowland alluvial landscapes

hydrogen concentrations on c class asteroids derived from remote sensing we present spectroscopic observations of 16 asteroids from 1 9 3 6 m collected from the united kingdom infrared telescope ukirt from 1996 2000 of these 16 asteroids 11 show some evidence of a 3 m hydrated mineral absorption feature greater than 2 at 2 9 m using relations first recognized for carbonaceous chondrite powders by miyamoto and zolensky 1994 and sato et al 1997 we have determined the hydrogen to silicon ratio for these asteroids and calculated their equivalent water contents assuming all the hydrogen was in water the asteroids split into 2 groups roughly defined as equivalent water contents greater than 7 8 asteroids all with 3 m band depths greater than 20 and less than 3 for the remaining 8 asteroids this latter group includes some asteroids for which a weak but statistically significant 3 m band of non zero depth exists the g class asteroids in the survey have higher water contents consistent with cm chondrites this strengthens the connection between cm chondrites and g asteroids that was proposed by burbine 1998 we find that the 0 7 m and 3 m band depths are correlated for the population of target objects

the taxonomic distribution of asteroids from multi filter all sky photometric surveys abstract the distribution of asteroids across the main belt has been studied for decades to understand the current compositional distribution and what that tells us about the formation and evolution of our solar system all sky surveys now provide orders of magnitude more data than targeted surveys we present a method to bias correct the asteroid population observed in the sloan digital sky survey sdss according to size distance and albedo we taxonomically classify this dataset consistent with the bus and binzel bus s j binzel r p 2002 icarus 158 146 177 and bus demeo et al demeo f e binzel r p slivan s m bus s j 2009 icarus 202 july 160 180 systems and present the resulting taxonomic distribution the dataset includes asteroids as small as 5 km a factor of three in diameter smaller than in previous work such as by mothe diniz et al mothe diniz t carvano j m a lazzaro d 2003 icarus 162 march 10 21 because of the wide range of sizes in our sample we present the distribution by number surface area volume and mass whereas previous work was exclusively by number while the distribution by number is a useful quantity and has been used for decades these additional quantities provide new insights into the distribution of total material we find evidence for d types in the inner main belt where they are unexpected according to dynamical models of implantation of bodies from the outer solar system into the inner solar system during planetary migration levison h f bottke w f gounelle m morbidelli a nesvorn d tsiganis k 2009 nature 460 july 364 366 we find no evidence of s types or other unexpected classes among trojans and hildas albeit a bias favoring such a detection finally we estimate for the first time the total amount of material of each class in the inner solar system the main belt s most massive classes are c b p v and s in decreasing order excluding the four most massive asteroids 1 ceres 2 pallas 4 vesta and 10 hygiea that heavily skew the values primitive material c p types account for more than half main belt and trojan asteroids by mass most of the remaining mass being in the s types all the other classes are minor contributors to the material between mars and jupiter

mineralogy and temperature of crater haulani on ceres we investigate the region of crater haulani on ceres with an emphasis on mineralogy as inferred from data obtained by dawn s visible infrared mapping spectrometer vir combined with multispectral image products from the dawn framing camera fc so as to enable a clear correlation with specific geologic features haulani which is one of the youngest craters on ceres exhibits a peculiar blue visible to near infrared spectral slope and has distinct color properties as seen in multispectral composite images in this paper we investigate a number of spectral indices reflectance spectral slopes abundance of mg bearing and nh4 bearing phyllosilicates nature and abundance of carbonates which are diagnostic of the overall crater mineralogy plus a temperature map that highlights the major thermal anomaly found on ceres in addition for the first time we quantify the abundances of several spectral endmembers by using vir data obtained at the highest pixel resolution 0 1 km the overall picture we get from all these evidences in particular the abundance of na and hydrous na carbonates at specific locations confirms the young age of haulani from a mineralogical viewpoint and suggests that the dehydration of na carbonates in the anhydrous form na2co3 may be still ongoing

a case study of convective organization into precipitating lines in the southwest amazon during the wetamc and trmm lba 1 a case study of convective development in the southwest amazon region during the wet season atmospheric mesoscale campaign wetamc and tropical rainfall measuring mission trmm large scale biosphere atmosphere lba experiment in amazonia is presented the convective development during 7 february 1999 is shown to occur during a period of very weak large scale forcing in the presence of topography and deforestation the available data include dual doppler radar analysis radiosonde launches and surface and boundary layer observations the observational analysis is complemented with a series of model simulations using the rams with 2 km resolution over a 300 km 300 km area forced by a morning radiosonde profile a comparison of the observed and simulated thermodynamic transformation of the boundary layer and of the formation of convective lines and of their kinematic and microphysical properties is presented it is shown that only a few very deep and intense convective cells are necessary to explain the overall precipitating line formation and that discrete propagation and coupling with upper atmosphere circulations may explain the appearance of several lines the numerical simulation indicates that topography may be the cause of initial convective development although later on the convective line is parallel to the midlevel shear there are indications that small scale deforestation may have an effect on increasing rainfall in the wet season when the large scale forcing is very weak

accurate determination of the pleistocene uplift rate of the ne japan forearc from the buried mis 5e marine terrace shoreline angle abstract we used tephra and phytolith stratigraphy to refine pleistocene marine terrace chronology with reference to reported eustatic sea levels associated with the dated marine terraces and estimated uplift rates along the northern part of the northeast ne japan forearc the overriding plate in the northeast japan subduction zone by using elevation measurements of the buried shoreline angle beneath well dated marine terrace surfaces to derive more accurate paleo sea levels on the kamikita plain northernmost honshu island the t4 and t3 marine terraces were correlated to marine isotope stage mis 5e and mis 7c or 7e respectively by the stratigraphic positions of the tephras toya mis 5d and wp mis 7b the t2 terrace surface which had previously been assigned to mis 7 is buried by loess correlated to mis 8 by its phytolith assemblage therefore this terrace can be reasonably re correlated to mis 9 the reported optically stimulated luminescence ages for middle pleistocene terrace deposits tend to be younger than these refined terrace ages we used the buried shoreline angle elevation determined from the reconstructed profile of the marine terrace deposits and paleo sea cliff to refine the uplift rate of t4 since mis 5e the accurate rate thus determined 0 18 0 26 m ky is slower than the rates initially inferred from the inner edge of t4 but faster than the reported rate 0 14 0 19 m ky as recalculated here inferred from the assumed mis 5e shoreline elevation in addition it is roughly compatible with the rate inferred by using the top of t2 lagoon deposits to determine the shoreline elevation during mis 9 therefore during the last 300 ka the uplift rate of the kamikita plain has been constant at about 0 2 m ky this pleistocene uplift is probably attributable to a combination of moment release on the megathrust isostatic uplift driven by crustal thickening and reverse faulting of the upper crust

ceres evolution and current state 1 we modeled several thermal evolution scenarios for ceres to explore the nature of large wet protoplanets and to predict current day evidence that might be found by close inspection such as by the dawn mission the density for ceres is near 2 1 suggesting a water content between 17 and 27 by mass short and long lived radioactive nuclide heating is considered even if only long lived radionuclide heating is assumed the water ice in ceres melts quickly and a water mantle forms but an approximately 10 km crust does not melt the circulating warm water would alter the silicates as heat is lost by conduction through the frozen crust water begins to freeze out at the base of the crust solid state convection begins and transports more heat as well as perhaps material dissolved or entrained in the water to or near the surface ceres water layer eventually but perhaps not entirely freezes forming a layered density structure with perhaps some liquid water remaining today our differentiated models are in agreement with the recently measured difference between the equatorial and polar radii we find that ceres existence and evolution depend critically on it containing water at formation and this depends strongly on the combination of when it accreted and the amount of 26al present in the pre ceres 1 km sized objects slightly more 26al or earlier accretion produces a dry vesta like object melting and freezing plus mineralization would lead to several dimensional changes over time creating topographic features zones of weakness and perhaps disruptions in the crust

age estimates of coastal terraces in the andaman and nicobar islands and their tectonic implications the great indian ocean earthquake of december 26 2004 caused significant vertical changes in its rupture zone about 800 km of the rupture is along the andaman and nicobar islands which forms the outer arc ridge of the subduction zone coseismic deformation along the exposed land could be observed as uplift subsidence here we analyze the morphological features along the coast of the andaman and nicobar islands in an effort to reconstruct the past tectonics taking cues from the coseismic effects we obtained radiocarbon dates from coastal terraces of the island belt and used them to compute uplift rates which vary from 1 33 mm yr 1 in the little andaman to 2 80 mm yr 1 in south andaman and 2 45 mm yr 1 in the north andaman our radiocarbon dates converge on sim 600 yr and sim 1000 yr old coastal uplifts which we attribute to the level changes due to two major previous subduction earthquakes in the region

holocene coastal uplift in the western pacific rim in the context of late quaternary uplift abstract this paper reviews recent studies of holocene coastal uplift in tectonically active areas near the plate boundaries of the western pacific rim emergent holocene terraces exist along the coast of north island of new zealand the huon peninsula of papua new guinea the japanese islands and taiwan these terraces have several features in common all comprise series of subdivided terraces the highest terrace is a constructional terrace underlain by estuarine or marine deposits and the lower terraces are erosional cutting into transgressive deposits or bedrock the highest terrace records the culmination of holocene sea level rise at ca 6 6 5 ka bp lower terraces were coseismically uplifted repeated major earthquakes have usually occurred at ka intervals and meter scale uplift the maximum uplift rate and number of terraces are surprisingly similar about 4 m ka and seven to four major steps in north island huon peninsula and japan taiwan especially along the east coast of the coastal range is different reaching a maximum uplift rate of 15 m ka with 10 subdivided steps they record a very rapid uplift comparison between short term holocene and long term since the last interglacial maximum sub stage 5e uplift rates demonstrates that a steady uplift rate huon peninsula or accelerated uplift toward the present several areas of japan and north island has continued at least since isotope sub stage 5e rapid uplift in eastern taiwan probably started only in the early holocene judging from the absence of any older marine terraces most of the causative faults for the coastal uplift may be offshore reverse faults branched from the main plate boundary fault but some of them are onshore faults which deformed progressively with time

late holocene earthquakes on the toe jam hill fault seattle fault zone bainbridge island washington five trenches across a holocene fault scarp yield the first radiocarbon measured earthquake recurrence intervals for a crustal fault in western washington the scarp the first to be revealed by laser imagery marks the toe jam hill fault a north dipping backthrust to the seattle fault folded and faulted strata liquefaction features and forest soil a horizons buried by hanging wall collapse colluvium record three or possibly four earthquakes between 2500 and 1000 yr ago the most recent earthquake is probably the 1050 1020 cal calibrated yr b p a d 900 930 earthquake that raised marine terraces and triggered a tsunami in puget sound vertical deformation estimated from stratigraphic and surface offsets at trench sites suggests late holocene earthquake magnitudes near m7 corresponding to surface ruptures 36 km long deformation features recording poorly understood latest pleistocene earthquakes suggest that they were smaller than late holocene earthquakes postglacial earthquake recurrence intervals based on 97 radiocarbon ages most on detrital charcoal range from 12 000 yr to as little as a century or less corresponding fault slip rates are 0 2 mm yr for the past 16 000 yr and 2 mm yr for the past 2500 yr because the toe jam hill fault is a backthrust to the seattle fault it may not have ruptured during every earthquake on the seattle fault but the earthquake history of the toe jam hill fault is at least a partial proxy for the history of the rest of the seattle fault zone

stress transferred by the 1995 mw 6 9 kobe japan shock effect on aftershocks and future earthquake probabilities the kobe earthquake struck at the edge of the densely populated osaka kyoto corridor in southwest japan we investigate how the earthquake transferred stress to nearby faults altering their proximity to failure and thus changing earthquake probabilities we find that relative to the pre kobe seismicity kobe aftershocks were concentrated in regions of calculated coulomb stress increase and less common in regions of stress decrease we quantify this relationship by forming the spatial correlation between the seismicity rate change and the coulomb stress change the correlation is significant for stress changes greater than 0 2 1 0 bars 0 02 0 1 mpa and the nonlinear dependence of seismicity rate change on stress change is compatible with a state and rate dependent formulation for earthquake occurrence we extend this analysis to future mainshocks by resolving the stress changes on major faults within 100 km of kobe and calculating the change in probability caused by these stress changes transient effects of the stress changes are incorporated by the state dependent constitutive relation which amplifies the permanent stress changes during the aftershock period earthquake probability framed in this manner is highly time dependent much more so than is assumed in current practice because the probabilities depend on several poorly known parameters of the major faults we estimate uncertainties of the probabilities by monte carlo simulation this enables us to include uncertainties on the elapsed time since the last earthquake the repeat time and its variability and the period of aftershock decay we estimate that a calculated 3 bar 0 3 mpa stress increase on the eastern section of the arima takatsuki tectonic line attl near kyoto causes fivefold increase in the 30 year probability of a subsequent large earthquake near kyoto a 2 bar 0 2 mpa stress decrease on the western section of the attl results in a reduction in probability by a factor of 140 to 2000 the probability of a mw 6 9 earthquake within 50 km of osaka during 1997 2007 is estimated to have risen from 5 6 before the kobe earthquake to 7 11 afterward during 1997 2027 it is estimated to have risen from 14 16 before kobe to 16 22

cryovolcanic features on titan s surface as revealed by the cassini titan radar mapper abstract the cassini titan radar mapper obtained synthetic aperture radar images of titan s surface during four fly bys during the mission s first year these images show that titan s surface is very complex geologically showing evidence of major planetary geologic processes including cryovolcanism this paper discusses the variety of cryovolcanic features identified from sar images their possible origin and their geologic context the features which we identify as cryovolcanic in origin include a large 180 km diameter volcanic construct dome or shield several extensive flows and three calderas which appear to be the source of flows the composition of the cryomagma on titan is still unknown but constraints on rheological properties can be estimated using flow thickness rheological properties of one flow were estimated and appear inconsistent with ammonia water slurries and possibly more consistent with ammonia water methanol slurries the extent of cryovolcanism on titan is still not known as only a small fraction of the surface has been imaged at sufficient resolution energetic considerations suggest that cryovolcanism may have been a dominant process in the resurfacing of titan

late quaternary uplift rate inferred from marine terraces muroto peninsula southwest japan forearc deformation in an oblique subduction zone abstract tectonic uplift rates across the muroto peninsula in the southwest japan forearc the overriding plate in the southwest japan oblique subduction zone were estimated by mapping the elevations of the inner edges of marine terrace surfaces the uplift rates inferred from marine terraces m1 and m2 which were correlated by tephrochronology with marine isotope stages mis 5e and 5c respectively include some vertical offset by local faults but generally decrease northwestward from 1 2 1 6 m ky 1 on cape muroto to 0 3 0 7 m ky 1 in the kochi plain the vertical deformation of the muroto peninsula since mis 5e and 5c was interpreted as a combination of regional uplift and folding related to the arc normal offshore muroto misaki fault a regional uplift rate of 0 46 m ky 1 was estimated from terraces on the muroto peninsula and the residual deformation of these terraces was attributed to fault related folding a mass balance calculation yielded a shortening rate of 0 71 0 77 m ky 1 for the muroto peninsula with the muroto misaki fault accounting for 0 60 0 71 m ky 1 but these rates may be overestimated by as much as 10 given variations of several meters in the elevation difference between the buried shoreline angles and terrace inner edges in the study area a thrust fault model with flat 5 10 dip and ramp 60 dip components is proposed to explain the shortening rate and uplift rate of the muroto misaki fault since mis 5e bedrock deformation also indicates that the northern extension of this fault corresponds to the older muroto flexure

predicted crater morphologies on ceres probing internal structure and evolution the detailed internal structure of the dwarf planet ceres target of nasa s dawn mission has not been unequivocally determined from ground based data whereas ceres is most likely differentiated with a near surface ice layer tens to one hundred kilometers thick the possibility of a homogenous ice poor interior structure cannot be completely eliminated these two internal structural end members have profoundly different implications for ceres origin and evolution here we demonstrate that observations of ceres impact craters by the dawn spacecraft will permit unambiguous distinction between the two internal structural models using finite element simulations of crater relaxation we show that if ceres does contain a water ice layer its relatively warm diurnally averaged surface temperature ensures extensive viscous relaxation of even small impact craters at likely equatorial temperatures craters as small as 4km in diameter can be relaxed to the point where complete crater erasure is plausible thus decreasing the overall crater density in the equatorial region at mid latitudes crater relaxation is less extensive but still sufficient to completely relax all craters older than 10 ma and larger than 16 km in diameter as well as smaller ancient craters only in ceres cold polar regions are some crater morphologies expected to be pristine in contrast if ceres is primarily a rocky body we expect crater relaxation to be negligible these basic conclusions are generally independent of ice grain size salt dust contamination of the ice the presence of a thin undifferentiated ice rock crust and the total thickness of the ice layer all of which produce second order modifications to the relaxation process that can be used to better constrain such ice layer properties thus the morphology of impact craters on ceres as revealed by the dawn spacecraft will provide direct insight into the internal structure and evolution of the dwarf planet