working models for spatial distribution and level of mars seismicity 1 we present synthetic catalogs of mars quakes intended to be used for performance assessments of future seismic networks on the planet we have compiled a new inventory of compressional and extensional tectonic faults for the planet mars comprising 8500 faults with a total length of 680 000 km the faults were mapped on the basis of mars orbiting laser altimeter mola shaded relief hence we expect to have assembled a homogeneous data set not biased by illumination and viewing conditions of image data updated models of martian crater statistics and geological maps were used to assign new maximum ages to all faults on the basis of the fault catalog spatial distributions of seismicity were simulated using assumptions on the available annual seismic moment budget the moment frequency relationship and a relation between rupture length and released moment we have constructed five different models of martian seismicity predicting an annual moment release between 3 42 1016 nm and 4 78 1018 nm and up to 572 events with magnitudes greater than 4 per year as upper limit end member case most events are expected on the tharsis shield but minor seismic centers are expected south of hellas and north of utopia planitia

possible long term decline in impact rates 1 martian geological data abstract quantin et al quantin c allemand p mangold n delacourt c 2004a icarus 172 555 572 tabulated crater count data for 56 landslides along the walls of valles marineris under the assumption of a constant cratering rate after about 3 gyr ago as used in the 1999 2005 iterations of the crater chronology isochron system of hartmann and in the hartmann and neukum system these data indicate a regularly increasing rate of landslides which would be difficult to explain we suggest that these data may support a decline in inner solar system cratering rates by about a factor of 3 since 3 gyr ago not unlike predictions based on asteroid belt collision models such a decline is also supported by our review of data on lunar impact melts and glass spherules in a companion paper hartmann w k quantin c mangold n 2007 icarus 186 11 23 such models produce not only a more uniform rate of landslides over the last 3 gyr but also a more uniform rate of resurfacing processes which also had an apparent increase under the assumption of a constant cratering rate

seismicity on tidally active solid surface worlds tidal interactions between planets or stars and the bodies that orbit them dissipate energy in their interiors the dissipated energy heats the interior and a fraction of that energy will be released as seismic energy here we formalize a model to describe the tidally driven seismic activity on planetary bodies based on tidal dissipation to constrain the parameters of our model we use the seismic activity of the moon driven by tidal dissipation from the earth moon interactions we then apply this model to predict the amount of seismic energy release and largest seismic events on other moons in our solar system and exoplanetary bodies we find that many moons in the solar system should be more seismically active than the earth s moon and many exoplanets should exhibit more seismic activity than the earth finally we examine how temporal spatial variations in tidal dissipation manifest as variations in the locations and timing of seismic events on these bodies

the formation and failure of natural dams of the numerous kinds of dams that form by natural processes dams formed from landslides glacial ice and late neoglacial moraines present the greatest threat to people and property landslide dams form in a wide range of physiographic settings the most common types of mass movements that form landslide dams are rock and debris avalanches rock and soil slumps and slides and mud debris and earth flows the most common initiation mechanisms for dam forming landslides are excessive rainfall and snowmelt and earthquakes landslide dams can be classified into six categories based on their relation with the valley floor type i dams 11 of 184 landslide dams from around the world that we were able to classify do not reach from one valley side to the other type ii dams 44 span the entire valley floor in some cases depositing material high on opposite valley sides type iii dams 41 move considerable distances both upstream and downstream from the landslide failure type iv dams 1 are rare and involve the contemporaneous failure of material from both sides of a valley type v dams 1 also are rare and are created when a single landslide sends multiple tongues of debris into a valley and forms two or more landslide dams in the same reach of river type vi dams 3 involve one or more failure surfaces that extend under the stream or valley and emerge on the opposite valley side many landslide dams fail shortly after formation in our sample of 73 documented landslide dam failures 27 of the landslide dams failed less than 1 day after formation and about 50 failed within 10 days over topping is by far the most common cause of failure the timing of failure and the magnitude of the resulting floods are controlled by dam size and geometry material characteristics of the blockage rate of inflow to the impoundment size and depth of the impoundment bedrock control of flow and engineering controls such as artificial spill ways diversions tunnels and planned breaching by blasting or conventional excavation glacial ice dams can produce at least nine kinds of ice dammed lakes the most dangerous are lakes formed in main valleys dammed by tributary glaciers failure can occur by erosion of a drainage tunnel under or through the ice dam or by a channel over the ice dam cold polar ice dams generally drain supraglacially or marginally by downmelting of an outlet channel warmer temperate ice dams tend to fail by sudden englacial or subglacial breaching and drainage late neoglacial moraine dammed lakes are located in steep mountain areas affected by the advances and retreats of valley glaciers in the last several centuries these late neoglacial dams pose hazards because 1 they are sufficiently young that vegetation has not stabilized their slopes 2 many dam faces are steeper than the angle of repose 3 these dams and lakes are immediately downslope from steep crevassed glaciers and near vertical rock slopes and 4 downstream from these dams are steep canyons with easily erodible materials that can be incorporated in the flow and increase flood peaks the most common reported failure mechanism is overtopping and breaching by a wave or series of waves in the lake generated by icefalls rockfalls or snow or rock avalanches melting of ice cores or frozen ground and piping and seepage are other possible failure mechanisms natural dams may cause upstream flooding as the lake rises and downstream flooding as a result of failure of the dam although data are few for the same potential energy at the dam site ownstream flood peaks from the failure of glacier ice dams are smaller than those from landslide moraine and structed earth fill and rock fill dam failures moraine dam failures appear to produce some of the largest downstream flood peaks for potential energy at the dam site greater than 1011 1012 joules differences in flood peaks natural dam failures appear to be controlled by dam characteristics and failure mechanisms

expected seismicity and the seismic noise environment of europa seismic data will be a vital geophysical constraint on internal structure of europa if we land instruments on the surface quantifying expected seismic activity on europa both in terms of large recognizable signals and ambient background noise is important for understanding dynamics of the moon as well as interpretation of potential future data seismic energy sources will likely include cracking in the ice shell and turbulent motion in the oceans we define a range of models of seismic activity in europa s ice shell by assuming each model follows a gutenberg richter relationship with varying parameters a range of cumulative seismic moment release between 10 16 and 10 18 nm yr is defined by scaling tidal dissipation energy to tectonic events on the earth s moon random catalogs are generated and used to create synthetic continuous noise records through numerical wave propagation in thermodynamically self consistent models of the interior structure of europa spectral characteristics of the noise are calculated by determining probabilistic power spectral densities of the synthetic records while the range of seismicity models predicts noise levels that vary by 80 db we show that most noise estimates are below the self noise floor of high frequency geophones but may be recorded by more sensitive instruments the largest expected signals exceed background noise by 50 db noise records may allow for constraints on interior structure through autocorrelation models of seismic noise generated by pressure variations at the base of the ice shell due to turbulent motions in the subsurface ocean may also generate observable seismic noise

intraplate earthquakes and the state of stress in oceanic lithosphere abstract the sources of stress responsible for oceanic intraplate earthquakes and their usefulness for inferring the tectonic stress field are investigated through a synthesis of the source mechanisms of 58 of the largest such events determined by inversion of long period p and sh waveforms further constraints are provided by the global distribution of oceanic intraplate seismicity and a calculation of the seismic moment release per unit volume of seismogenic lithosphere as a function of lithosphere age although frequently associated with relict tectonic features large oceanic intraplate earthquakes are generally reliable indicators of the state of stress in the source region most oceanic intraplate seismicity occurs in young lithosphere

230th u dating of last interglacial brain corals from bonaire southern caribbean using bulk and theca wall material abstract we compared the suitability of two skeletal materials of the atlantic brain coral diploria strigosa for 230th u dating the commonly used bulk material comprising all skeletal elements and the denser theca wall material eight fossil corals of presumably last interglacial age from bonaire southern caribbean sea were investigated and several sub samples were dated from each coral for four corals both the ages and the activity ratios of the bulk material and theca wall agree within uncertainty three corals show significantly older ages for their bulk material than for their theca wall material as well as substantially elevated 232th content and 230th 238u ratios the bulk material samples of another coral show younger ages and lower 230th 238u ratios than the corresponding theca wall samples this coral also contains a considerable amount of 232th the application of the available open system models developed to account for post depositional diagenetic effects in corals shows that none of the models can successfully be applied to the bonaire corals the most likely explanation for this observation is that the assumptions of the models are not fulfilled by our data set comparison of the theca wall and bulk material data enables us to obtain information about the open system processes that affected the corals the corals showing apparently older ages for their bulk material were probably affected by contamination with a secondary detrital phase the most likely source of the detrital material is carbonate sand the higher 230th 232th ratio of this material implies that detrital contamination would have a much stronger impact on the ages than a contaminant with a bulk earth 230th 232th ratio and that the threshold for the commonly applied 232th reliability criterion would be much lower than the generally used value of 1 ng g 1 the coral showing apparently younger ages for its bulk material was probably influenced by more than one diagenetic process a potential scenario is a combination of detrital contamination and u addition by secondary pore infillings our results show that the dense theca wall material of d strigosa is generally less affected by post depositional open system behaviour and better suited for 230th u dating than the bulk material this is also obvious from the fact that all ages of theca wall material reflect a last interglacial origin 125 ka whereas the bulk material samples are either substantially older or younger however for some corals the 230th u ages and activity ratios of the bulk material and the theca wall samples are similar this shows that strictly reliable 230th u ages can also be obtained from bulk material samples of exceptionally well preserved corals however the bulk material samples more frequently show elevated activity ratios and ages than the corresponding theca wall samples our findings should be generally applicable to brain corals mussidae that are found in tropical oceans worldwide and may enable reliable 230th u dating of fossil corals with similar skeletal architecture even if their bulk skeleton is altered by diagenesis the 230th u ages we consider reliable 120 130 ka along with a recently published age of 118 ka provide the first comprehensive dating of the elevated lower reef terrace at bonaire 118 130 ka which is in agreement in timing and duration with other last interglacial records

seismic response of the mars curiosity rover implications for future planetary seismology abstract seismic measurements are an important tool for exploration of planetary interiors but may not be included in missions due to perceived complexity in placement of sensitive instruments on the surface to help address this concern we assess the fidelity of recordings of ground motion by an instrument placed on the deck of the engineering model of the mars science laboratory compared with an identical instrument placed on the ground directly beneath comparison of the recordings reveals clear recordings of teleseismic earthquakes on both instruments the transfer function between the instruments demonstrates the deck instrument is affected by resonance frequencies of the lander and does not faithfully record ground motion at these frequencies or higher in addition additional decoherence is observed near 1 hz during periods of strong airflow due to air conditioning cycling however excellent coherence and a transfer function near 1 can be observed in the important seismic band between 2 and 30 s at all times and extending up to the lander resonances during the night time when air conditioning was not running this suggests a deck mounted seismic instrument may be able to provide valuable science return without requiring additional deployment complexity

graben and extension in northern tharsis mars a morphometric analysis of north south trending graben at 35 n in northern tharsis is used to provide the first quantitative measurements of crustal extension in and strain for areas of the martian crust that have undergone both extreme and mild deformation these estimates also demonstrate the viability of the viking data for making such quantitative assessment graben in the region accommodate 8 km of post early amazonian east west extension this extension corresponds to a net regional strain of 0 45 0 61 local strains vary from 1 to 5 extension is nonuniform and localized near 110 south of alba patera and north of ceraunius fossae because of reactivation of preexisting fractures in underlying basement and possibly due to superposition of stress fields from tharsis and alba patera a major mechanical discontinuity in the shallow crust probably representing the base of or a strength contrast within the megaregolith is observed it occurs at a depth of 2 km on the profile flanks and is depressed to about 7 5 km near 110 due to loading of the crust by the volcano a number of more shallow discontinuities occur within the construct and probably represent lithologic contacts

discontinuities in the shallow martian crust at lunae syria and sinai plana detailed photoclinometric profiles across 125 erosional features and 141 grabens in the western equatorial region of mars indicate the presence of three discontinuities within the shallow crust pits troughs and wall valleys tributary canyons within noctis labyrinthus and valles marineris and escarpments within the fretted terrain of sacra fossae and kasei valles show distinct erosional base levels at depths of 0 3 0 6 km 1 km and 2 3 km the shallowest discontinuity corresponds to thickness estimates for the ridged plains unit in this region and thus the discontinuity probably is the contact between a sequence of layered rock making up this unit and the underlying megaregolith the 1 km discontinuity is reflected in the base levels of erosion of all the features studied and it may correspond to the base of the proposed layer of ground ice model calculations using photoclinometric profiles of simple grabens corrected for the effects of mass wasting and the 60 dip of bounding faults measured from the exposed traces of faults on trough walls show that graben bounding faults consistently intersect at the mechanical discontinuity at about 1 km depth this discontinuity may represent an interface between ice laden and dry regolith ice laden and water laden regolith or pristine and cemented regolith a correlation between wall valley head depth and local thickness of the faulted layer suggests that the 1 km discontinuity also controlled the depth of the heads of sapping canyons there is no apparent relation between the pit and trough depths and the local thickness of the faulted layer which can be explained if pits and troughs developed by subsidence into underlying tension cracks that disrupted the 1 km discontinuity the data do suggest however that erosion of shallow pits and troughs was influenced by the 1 km discontinuity the third discontinuity at a depth of 2 3 km corresponds to the proposed base of the martian megaregolith and is probably the interface between overlying ejected breccia and in situ fractured basement rocks

crosscutting relations and relative ages of ridges and faults in the tharsis region of mars abstract observations of ridge fault crosscutting relationships on the ridged plains units surrounding the tharsis region of mars have led to the development of a classification scheme involving three distinct types of intersections ridges crosscut by faults are designated type c and account for 81 of the observed intersections ridges terminated at one end by a fault type t as well as those superposed on grabens type s are less numerous interpretation of the morphology of these intersections and the angles of intersection between ridges and faults with radial trends to major topographic features in the tharsis region have led to the following conclusions 1 the major ridge forming events in the tharsis region were roughly coincident with and in some cases possibly prior to the extensional events that produced the faulting of the tempe and mareotis regions the coprates and memnonia regions and the rifting of valles marinrris 2 the compressional events that formed most of the ridges are restricted in time both by the irrelationship to regional extensional events and by the age of the units on which they formed the suggestion that compressional ridges are a result of a single long term viscoelastic response of the lithosphere to loading of the crust is not supported by this study a model involving one or more isostatically compensated uplifts and subsequent relaxation of the crust after the emplacement of the ridged plains volcanic units is favored

a pleistocene landslide dammed lake indicated by karren features eastern alps austria abstract numerous enigmatic tube shaped holes in the limestone ceilings of overhangs and small caves in a restricted area north of the village st aegyd am neuwalde lower austria have been known at least since 1933 but so far no detailed study concerning their origin has been conducted the vertical holes occur in middle triassic limestone and they are almost perfect cylinders tapering gently to a rounded apex their diameters are up to 5 5 cm and their depths reach 45 cm they occur on both sides of the unrechttraisen valley located in the north eastern part of the northern calcareous alps almost identical features were described from the shores of lakes in western ireland and termed rohrenkarren or tube karren simms 2002 according to simms model they have formed by condensation corrosion within air pockets trapped in limestone overhangs by rising water levels during floods the occurrence of these features is surprising because presently there is no lake and so far no palaeolake has been known from this area based on high resolution airborne laser scanning data and detailed field observations a landslide deposit was identified in a narrow section of the valley downstream of the rohrenkarren sites fine grained partly laminated sediments with abundant dragonfly anisoptera or flatworm turbellaria eggs indicative of lacustrine sediments up to ca 100 m above present river bed these data indicate that a landslide had dammed the unrechttraisen river resulting in a ca 100 m deep lake the rohrenkarren have formed due to fluctuations of the lake level resulting from differences in river run off and seepage through the landslide dam since 230th u dating of calcite crusts covering some rohrenkarren was not successful the age is not well constrained

mars chronology assessing techniques for quantifying surficial processes abstract currently the absolute chronology of martian rocks deposits and events is based mainly on crater counting and remains highly imprecise with epoch boundary uncertainties in excess of 2 billion years answers to key questions concerning the comparative origin and evolution of mars and earth will not be forthcoming without a rigid martian chronology enabling the construction of a time scale comparable to earth s priorities for exploration include calibration of the cratering rate dating major volcanic and fluvial events and establishing chronology of the polar layered deposits if extinct and or extant life is discovered the chronology of the biosphere will be of paramount importance many radiometric and cosmogenic techniques applicable on earth and the moon will apply to mars after certain baselines e g composition of the atmosphere trace species chemical and physical characteristics of martian dust are established the high radiation regime may pose a problem for dosimetry based techniques e g luminescence the unique isotopic composition of nitrogen in the martian atmosphere may permit a mars specific chronometer for tracing the time evolution of the atmosphere and of lithic phases with trapped atmospheric gases other mars specific chronometers include measurement of gas fluxes and accumulation of platinum group elements pge in the regolith putting collected samples into geologic context is deemed essential as is using multiple techniques on multiple samples if in situ measurements are restricted to a single technique it must be shown to give consistent results on multiple samples but in all cases using two or more techniques e g on the same lander will reduce error while there is no question that returned samples will yield the best ages in situ techniques have the potential to be flown on multiple missions providing a larger data set and broader context in which to place the more accurate dates

cave development by frost weathering abstract this paper deals with the description and genesis of a special type of shelter cave in german they are termed auswitterungshohlen which goes back to the 19th century and the genesis is supposed to be related to frost weathering but to our knowledge detailed studies are missing so far this type of cave is very common in the area of investigation that comprises pre alpine and alpine regions in the north eastern part of the eastern alps they make up 32 of the 5138 registered caves but surprisingly they entirely developed in carbonate rocks although most of them are smaller than a dozen metres some have lengths of more than 50 m and entrances can be more than 100 m wide or similarly high besides general observations that lead to a list of characteristics for these caves two of them in a pre alpine setting were studied in depth a detailed map descriptions and measurements concerning cave morphology host rock geology and climate are given the thickness and composition of clastic sediments were investigated by small trenches and electric resistivity measurements sediment thicknesses reach up to 2 m inside the caves and below the entrances for one year nets were installed to measure rockfall in both caves in warm periods generally less than 5 g month of debris could be collected but a few 100 g month for frost periods this strong correlation and the significant amount of debris together with other observations suggest that frost weathering is an on going and very important process for the formation of these caves grain size distribution of the collected debris argues for the activity of both microgelivation and ice segregation therefore we suggest that the term frost weathering caves should be used for shelter caves whose genesis is related to frost weathering as dissolution seems to be of marginal importance for the genesis they are a paradox as they develop in karstic rock but have pseudokarst features

seismic energy release of the moon previous estimates of the seismic energy released by lunar events have not properly accounted for instrument bandwidth variations in corner frequency and the effects of intense scattering in this paper equations are developed that include all of these effects and give realistic estimates for source parameters these equations are applied to seismograms and displacement spectra from near surface and deep moonquakes to obtain m0 seismic moment s seismic energy release eyr seismic energy released annually by each lunar event class stress drop and mb body wave magnitude the calculations yield m0 3 1021 dyn cm s 2 1017 ergs 400 bars and mb 5 0 for the largest shallow moonquakes and m0 5 1020 dyn cm s 1 1013 ergs 0 1 bars and mb 3 0 for large deep events the average energy released annually is eyr 2 1017 erg yr and eyr 8 1013 erg yr by shallow and deep events respectively overall lunar energy release is dominated by the shallow events the energy released by the deep events may be accounted for by tidal dissipation and deep event stress drops are comparable to and smaller than the calculated tidal stresses a comparison of the above values with those observed terrestrially eyr 1025 ergs and with the energy available from heat flow and tidal dissipation emphasizes the importance of tectonic style e g plate tectonics in determining the characteristics of planetary seismicity

interior structure of terrestrial planets modeling mars mantle and its electromagnetic geodetic and seismic properties 1 we present a new procedure to describe the one dimensional thermodynamical state and mineralogy of any earth like planetary mantle with mars as an example the model parameters are directly related to expected results from a geophysical network mission in this case electromagnetic geodetic and seismological processed observations supplemented with laboratory measurements we describe the internal structure of the planet in terms of a one dimensional model depending on a set of eight parameters for the crust the thickness and the mean density for the mantle the bulk volume fraction of iron the olivine volume fraction the pressure gradient and the temperature profile and for the core its mass and radius currently available geophysical and geochemical knowledge constrains the range of the parameter values in the present paper we develop the forward problem and present the governing equations from which synthetic data are computed using a set of parameter values among all martian models fitting the currently available knowledge we select eight candidate models for which we compute synthetic network science data sets the synergy between the three geophysical experiments of electromagnetic sounding geodesy and seismology is emphasized the stochastic inversion of the synthetic data sets will be presented in a companion paper

a geophysical perspective on the bulk composition of mars we invert the martian tidal response and mean mass and moment of inertia for chemical composition thermal state and interior structure the inversion combines phase equilibrium computations with a laboratory based viscoelastic dissipation model the rheological model which is based on measurements of anhydrous and melt free olivine is both temperature and grain size sensitive and imposes strong constraints on interior structure the bottom of the lithosphere defined as the location where the conductive geotherm meets the mantle adiabat occurs deep within the upper mantle 250 500 km depth resulting in apparent upper mantle low velocity zones assuming an fe fes core our results indicate 1 a mantle with a mg molar mg mg fe of 0 75 in agreement with earlier geochemical estimates based on analysis of martian meteorites 2 absence of bridgmanite and ferropericlase dominated basal layer 3 core compositions 13 5 16 wt s core radii 1640 1740 km and core mantle boundary temperatures 1560 1660 c that together with the eutectic like core compositions suggest the core is liquid and 4 bulk martian compositions that are overall chondritic with a fe si wt ratio of 1 63 1 68 we show that the inversion results can be used in tandem with geodynamic simulations to identify plausible geodynamic scenarios and parameters specifically we find that the inversion results are reproduced by stagnant lid convection models for a range of initial viscosities 1019 1020 pa s and radioactive element partitioning between crust and mantle around 0 001 the geodynamic models predict a mean surface heat flow between 15 25 mw m2

gps constraints on active deformation in the isparta angle region of sw turkey summary we use survey and continuous gps observations during the period 1997 2010 to investigate active deformation in the isparta angle region of sw anatolia turkey this region bordered bythefethiyeburdurfaultzone fbfz inthewestandtheseextensionoftheaksehirsimav fault zone aksfz in the east accommodates a part of the active deformation of w turkey our results show that the isparta angle region rotates counter clockwise ccw with respect to anatolia both the fbfz and the aksfz are predominantly transtensional boundaries that accommodate southward motion of the isparta region with respect to anatolia the fbfz has left lateral strike slip behaviour along its sw segment that changes to right lateral strike slip along its ne extension this change in the sense of strike slip motion is accommodated by extension on a nw se striking normal fault system that is associated with the menderes graben system transtensional fault systems along the boundaries of the isparta angle with anatoliaareinconsistentwithextrusionmodelsforpresent daysouthwardmotion anincrease in motion rates towards the hellenic and cyprus arc subduction systems and ccw of the isparta region supports dynamic models involving active rollback of the subducting african plate toroidal mantle flow around the eastern edge of the subducting african slab near the hellenic arc florence rise junction and or gravitational collapse of the overriding anatolia plate

uranium series dating of quaternary deposits abstract this is a review of u series dating methods as applicable to terrestrial sedimentary materials alpha counting techniques allow the dating of carbonates and phosphates with a precision of 5 to 10 over the time range from 1 ka to 350 ka atom counting methods mass spectrometry and ams substantially increase precision and may increase the range problems of contamination and open system behavior are discussed correction for detrital contaminant is demonstrated in the dating of speleothem from a cave in italy

tectonic history of the syria planum province of mars we attribute most of the development of extensive fractures in the tharsis region to discrete tectonic provinces within the region rather than to tharsis as a single entity one of these provinces is in syria planum faults and collapse structures in the syria planum tectonic province on mars are grouped into 13 sets based on relative age areal distribution and morphology according to superposition and fault crosscutting relations and crater counts we designate six distinct episodes of tectonic activity in the following chronologic order stage i is an early to late noachian deformation forming mostly east west structures fault set ia some large volcanoes also formed faults were produced possibly by flexural uplift also arcuate north trending grabens set ib indicate that faulting is transitional to the next stage stage ii is late noachian to early hesperian radial faulting centered in syria planum possibly due to isostatic uplift in late noachian set iia to early hesperian set iib time stage iii is early to late hesperian faulting tangential to syria planum that was related to local centers of uplift sets iii1 iii3 on the periphery of syria planum stage iv is a late hesperian graben formation that was circumferential to syria planum set iva caused either by collapse associated with eruption of magma or by flexure of the lithosphere due to volcanic loading in association with volcanism minor faulting occurred producing an oval pattern of faults in southwest syria planum set ivbl and a radial pattern south of the planum set ivb2 that apparently rejuvenated buried stage ii faults stage v is a late hesperian to early amazonian development of grabens and troughs of noctis labyrinthus and western valles marineris set v that was probably instigated by local uplift exposure of groundwater or ground ice zones may have produced further collapse and trough enlargement stage vi is early amazonian northwest trending faulting in noctis fossae set vil perhaps due to tharsis monies centered tectonism and north northwest normal faulting along the eastern side of the claritas rise set vi2 that was due to tectonic subsidence the duration of tectonic activity in the syria planum province was perhaps 2 3 b y photoclinometric topographic profiles across 132 grabens and fault scarps show that syria planum grabens have widths average of 2 5 km and most range from 1 to 6 km similar to lunar grabens but the martian grabens have slightly higher side walls average about 132 m and gentler wall slopes average of 9 and range of 2 25 than lunar grabens 93 m high and 18 slopes scarp degradation on mars has progressed through quakes impact shaking and dry slope processes the lower slopes may be due to mars higher gravity estimates of the amount of extension for individual grabens range from 20 to 350 m most estimates of the thickness of the faulted layer range from 0 5 to 4 5 km average is 1 5 km this thickness range corresponds closely to the 0 8 to 3 6 km range in depth for pits troughs and canyons in noctis labyrinthus and along the walls of valles marineris we propose that the predominant 1 to 1 5 km values obtained for both the thickness of the faulted layer and the depths of the pits troughs and theater heads of the canyons reflect the initial depth to the water table in this region as governed by the depth to the base of ground ice maximum depths for these features may indicate lowered groundwater table depths and the base of ejecta material

displacement length scaling for terrestrial and martian faults implications for valles marineris and shallow planetary grabens the displacement length ratio for the central composite graben in valles marineris inferred from topography and likely stratigraphic offsets to be d max l 4 6 x 10 3 is consistent with the scaling relations derived from terrestrial faults and grabens that also demonstrate a systematic variation in displacement with position along the structure the large 10 km depth in central valles marineris is therefore not unusual but rather should be expected for a fault system 2240 km long in contrast existing measurements of throw along the numerous shallow radial grabens in tharsis while apparently inconsistent with the scaling relations demonstrate the importance of recognizing mechanical segment length along linked or echelon graben sets faults on other planetary surfaces should scale with their terrestrial counterparts as long as they extend substantially deeper than the gravity dependent near surface rock mass zone 1 km for earth 2 5 km for mars

relict landslide development as inferred from speleothem deformation tectonic data and geoelectrics abstract the direct dating of pre and postfaulting dislocated calcite speleothems afforded new insight into slope failure in the tatra mountains in southern poland a multi approach study of the karstic kalacka cave non crevasse type enabled us to infer the slope deformation structure which had been poorly preserved in ground surface topography using combined methods including geomorphological and structural mapping of cave and ground surfaces paleostress analysis near surface electrical resistivity tomography ert and induced polarization methods ip uranium series dating 234u 230th calcite microtexture analysis and stable isotope 18o and 13c analysis here slope deformation began with dilation between 280 7 ka and 265 8 ka and proceeded as deep seated gravitational slope deformations the final stage consisted of dilation rejuvenation and rockfall during the latest pleistocene or holocene post 35 4 ka additionally some dilations are evident beyond the extent of the landslide detected by ert indicating further progradation of slope failure since this failure was initiated during the climatic transition from mis 9 to mis 8 stable isotope analysis of calcite flowstone layers was applied to test climate factors the correlation of calcite microtexture and 18o and 13c compositional changes with the interval of dilation activity indicates that regional environment factors chiefly an increase in precipitation probably contributed to slope destabilization

numerical assessment of the effects of topography and crustal thickness on martian seismograms using a coupled modal solution spectral element method abstract the past 4 decades of mars exploration have provided much information about the mars surface when its interior structure remains relatively poorly constrained today available data are compatible with a large range of model parameters seismology is able to provide valuable additional data but the number of seismographs will likely be quite limited specially in the early stage of future mars seismic networks it is thus of importance to be able to correctly isolate effects induced by the crust structure mars topography is characterized by spectacular reliefs like the tharsis bulge or the hellas basin and by the so called mars dichotomy the north hemisphere is made up of low altitude plains above a relatively thin crust when the south hemisphere is characterized by a thick crust sustaining high reliefs the aim of this paper is to study the effects induced on seismograms by the topography of the surface and crust mantle discontinuities synthetic seismograms were computed using the coupled spectral element modal solution method which reduces the numerical cost by limiting the use of the spectral element method to the regions where lateral variations like the presence of a topography are considered due to numerical cost this study is limited to long period and thus focuses on surface waves mainly on long period rayleigh waves we show that reliefs like the tharsis bulge or the hellas basin can induce an apparent velocity anomaly up to 0 5 when only the surface topography is introduced apparent anomalies can raise up to 1 0 when the surface topography is fully compensated by a mirror image topography of the crust mantle discontinuity travel time of surface wave are systematically increased for seismometers in the north hemisphere of mars and decreased in the south hemisphere when comparing effects on seismograms by the earth and mars topography we found them to be larger for the earth it is due to the fact that we work with a seismic velocity model of mars with a mean crust thickness of 110 km when the crust thickness has a mean value of 50 km for the earth when changing the mars model for a thinner crust with a mean thickness of 50 km effects by the topography on mars seismograms becomes of the same order when not larger than what is observed on the earth

unusually high stress drops associated with shallow moonquakes new estimates of stress drops and energy release associated with shallow moonquakes believed to represent the only lunar seismic events of tectonic origin have been made taking into account 1 properties of source spectra 2 radiation pattern of foci 3 anelastic attenuation of seismic waves 4 response of the seismometer and 5 intense scattering of seismic signals the results indicate that the three largest events show body wave magnitudes of mb 5 5 and stress drops of 100 mpa the values for stress drops are high compared with those generally associated with most terrestrial events but they are compatible with results predicted from thermoelastic models of the moon presence of high stresses in the lunar crust may indicate that at the beginning of its history the moon was originally molten not only in the outer surface region but throughout its whole volume

the search for active marsquakes using subpixel coregistration and correlation best practice and first results the state of seismic activity on mars is currently unknown on earth coseismic displacement has been observed using visible wavelength images and subpixel coregistration and correlation techniques we apply this method to mars with the cosi corr co registration of optically sensed images and correlation software package using high resolution imaging science experiment hirise images focusing on part of the cerberus fossae fault system we derive best practices for applying this method to the study of coseismic displacements on mars using a time series of eight overlapping hirise images we achieve pixel coregistration with a mean accuracy of about 1 50 of a pixel we see no clear evidence for coseismic displacement in this region during a time period of over 8 years one possible displacement signal 1 2 m of west east displacement over a length scale of about 50 m that has similarities to terrestrial coseismic deformation was dismissed as the result of incomplete correction of steep topography during the coregistration stage ancillary observations of recurring slope lineae rsl activity in the surrounding fault system offer no supporting evidence for the occurrence of coseismic displacement but do seem to suggest rsl activity that does not fit into previous seasonal timescales although it is unlikely that we have observed coseismic displacement in our study area during this time period the best practice method and the accuracy of our results offer encouragement for future studies hirise context camera and color and stereo surface imaging system images can be used to complement and independently verify in situ seismic observations by the insight interior exploration using seismic investigations geodesy and heat transport lander or source location changes from the exomars trace gas orbiter spacecraft

a prediction of mars seismicity from surface faulting the shallow seismicity of mars has been estimated by measurement of the total slip on faults visible on the surface of the planet throughout geologic time seismicity was calibrated with estimates based on surface structures on the moon and measured lunar seismicity that includes the entire seismogenic lithosphere results indicate that mars is seismically active today with a sufficient number of detectable marsquakes to allow seismic investigations of its interior

flank tectonics of martian volcanoes on the flanks of olympus mons is a series of terraces concentrically distributed around the caldera their morphology and location suggest that they could be thrust faults caused by compressional failure of the cone in an attempt to understand the mechanism of faulting and the possible influences of the interior structure of olympus mons we have constructed a numerical model for elastic stresses within a martian volcano in the absence of internal pressurization the middle slopes of the cone are subjected to compressional stress appropriate to the formation of thrust faults these stresses for olympus mons are 250 mpa if a vacant magma chamber is contained within the cone the region of maximum compressional stress is extended toward the base of the cone if the magma chamber is pressurized extensional stresses occur at the summit and on the upper slopes of the cone for a filled but unpressurized magma chamber the observed positions of the faults agree well with the calculated region of high compressional stress three other volcanoes on mars ascraeus mons arsia mons and pavonis mons possess similar terraces extending our analysis to other martian volcanoes we find that only these three and olympus mons have flank stresses that exceed the compressional failure strength of basalt lending support to the view that the terraces on all four are thrust faults

fault length statistics and implications of graben sets at candor mensa mars abstract the lengths of individual martian grabens from three spatially and temporally distinct regional sets are analyzed by a two dimensional window sampling method length distributions are influenced by fault growth and coalescence processes image resolution window size and the post faulting geologic history of the region cumulative length frequency distributions can be linear for graben lengths between 30 and 100 km with slopes on the area plot of 2 suggesting self similar growth of the graben array post faulting geologic processes contribute to concave cumulative length distributions on the log log plot with curtailment and truncation biases producing strongly non linear distributions for smaller and longer lengths respectively recent evidence for a positive correlation between stratigraphic throw and graben length from analogous terrestrial grabens implies that the magnitudes of throw and extensional strain may also be dependent on relative position along the martian grabens

localization of bedding plane slip and backthrust faults above blind thrust faults keys to wrinkle ridge structure a mechanically based model for wrinkle ridge development is developed that combines wrinkle ridge morphologies regional topographic offsets suggestive of subsurface thrust faults and folding of near surface layers this model provides explicit relationships between observed morphologic elements characteristic of wrinkle ridges and plausible mechanisms in the subsurface a key component that is absent in previous qualitative fault based scenarios for these structures as developed in this paper wrinkle ridges are the surface expression of anticlines that grow above a blind thrust fault as a result of both flexural slip folding of near surface strata and the nucleation and growth of echelon arrays of backthrust faults calculations of displacements both horizontal shortening and vertical uplift and coulomb stress change related to slip along blind thrust faults in the model demonstrate physically important spatial inhomogeneities in these quantities with revealing and useful implications 1 the ratio of shortening due to folding at the surface to the shortening due to faulting at depth is characteristically small for coupled wrinkle ridge blind thrust fault systems and decreases with increasing fault depth the depth of the blind thrust fault s upper tip thus profoundly influences the surface strains 2 folding and uplifted topography forming the topographic ridge are produced above the area of the slipping blind thrust fault plane horizontal and vertical deformation at the surface extend over several ridge widths or a total of at least 50 km for a 10 km wide ridge implying that topographic profiles and geologic studies must extend sufficiently far from the wrinkle ridge to fully characterize the surface deformation 3 calculations of coulomb stress changes suggest that fault slip can localize both bedding plane slip in overlying strata and new backthrust faults that propagate upward to become wrinkles on the trailing side of the ridge initiation of bedding plane slip in association with slip along the blind thrust fault likely determines whether the resulting surface structure becomes a wrinkle ridge or a lobate scarp wrinkle ridge spacing may also be related to stress changes associated with slip along the underlying blind thrust fault

seismic detection of meteorite impacts on mars abstract meteorite impacts provide a potentially important seismic source for probing mars interior it has recently been shown that new craters can be detected from orbit using high resolution imaging which means the location of any impact related seismic event could be accurately determined thus improving the constraints that could be placed on internal structure using a single seismic station this is not true of other seismic sources on mars such as sub surface faulting which require location using multiple seismic stations this study aims to determine the seismic detectability of meteorite impacts and assess whether they are a viable means of probing deep internal structure first we derive a relation between crater diameter and equivalent seismic moment based on observational data compiled from impact tests controlled explosions and earthquake seismology second this relation was combined with updated cratering rates based on newly observed craters to derive the impact induced seismicity on mars which we estimate to total 10 13 10 14 n m per year finally seismic waveform modelling was used to determine the detectability of these impacts based on reasonable assumptions about likely seismometer performance and background noise levels for our nominal noise instrument case we find that detectable impacts at teleseismic distances source receiver offsets greater than 60 are very rare and occur approximately once every 10 years for our most optimistic noise instrument case approximately one such event occurs each year this suggests that using solely meteorite impacts is not a reliable way of probing the martian interior although local impacts are more frequently detectable and could provide important constraints on near surface seismic properties

lead isotope variability in speleothems a promising new proxy for hydrological change first results from a stalagmite from western germany abstract we studied an aragonitic section of ca 6 cm length of stalagmite hbsh 1 from the huttenblaserschachthohle western germany 230 th u dating revealed that this section grew between 210 and 190 ka with a relatively uniform growth rate of 3 1 m a 1 for the first time we determined pb isotope ratios 207 pb 206 pb and 208 pb 206 pb in a stalagmite by laser ablation la icp ms in addition we analyzed various trace element mg al si p mn sr pb and th concentrations the results indicate that pb in hbsh 1 originated from two external sources i the regional galena pbs mineralization with high pb content as well as isotope ratios and ii the carbonate fraction in the host rock with low pb content as well as isotope ratios except for sr all trace elements show similar variations probably driven by the amount of infiltration into the cave system this is probably the result of the similar transport and incorporation mechanisms of these elements as colloids and or particles the pb isotope ratios also show a strong correlation with trace element variability strongly suggesting that the pb isotope variability in hbsh 1 has the potential to be used as a promising new proxy for hydrological change based on the observed variability we identify two phases from 204 9 to 201 5 and from 198 4 to 195 9 ka with enhanced water infiltration in the cave region between 210 0 and 204 9 201 5 and 198 4 as well as 195 9 and 190 0 ka less infiltration occurred

estimation of the seismic moment rate from an incomplete seismicity catalog in the context of the insight mission to mars we evaluate methods to estimate the global seismic moment rate of a planet from the k 1 largest events observed during a limited and possibly short time span as can be expected for example for lander missions to mars the feasibility of the approach is demonstrated with a temporary broadband seismometer that was recording in the mojave desert california for 86 days in 2014 and by application to the global centroid moment tensor cmt catalog subsets thereof and a catalog of stable continental regions seismicity from the largest event observed at goldstone alone m w approximate to 7 9 we estimate the earth s global moment rate to be 1 03 x 10 22 n m yr whereas an estimation based on the 10 strongest events yields a rate of 5 79 x 10 21 n m yr summation of 42 yr of global cmt solutions results in an average of 7 61 x 10 21 n m yr in general a 2 yr interval of global cmt solutions is sufficient to estimate the earth s annual moment rate to within a factor of 5 or better a series of numerical experiments with more than 560 million synthetic catalogs based on the tapered gutenberg richter distribution shows that the estimation is rather insensitive against an unknown slope of the distribution and that bias and variance of the estimator depend on the ratio between moment rate and corner moment of the size frequency distribution moment rates of published mars models differ by a factor of 1000 or more tests with simulated catalogs show that it will be possible to reject some of these models with data returned by nasa s insight mission after two years of nominal mission life time