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

seismic energy distribution in latitude and a possible tidal stress explanation abstract this paper utilizes a statistical technique to investigate the global seismic energy distribution in latitude the energy distribution in latitude has two peaks one in each of the northern and southern hemispheres with an axis of symmetry at about 10 n the two peaks for shallow earthquakes have an interval of 90 while those for intermediate and deep ones concentrate in low latitudes the twin peak distribution in energy of intermediate and deep earthquakes becomes more apparent with increasing depth almost no energy is released in the north and south pole areas the energy released in the northern hemisphere is about 30 greater than that in the southern hemisphere except for the focal depths from 100 to 150 km through a study of the shear stress component caused by the corresponding long period lunisolar potential it is found that the shear stress distribution due to lunisolar constant flattering wave m0s0 coincides with some of the above phenomena we conclude that the long period tidal shear stress may be one of the possible causes for the seismic energy release or a triggering effect

new views of lunar geoscience an introduction and overview beyond the earth the moon is the only planetary body for which we have samples from known locations the analysis of these samples gives us ground truth for numerous remote sensing studies of the physical and chemical properties of the moon and they are invaluable for our fundamental understanding of lunar origin and evolution prior to the return of the apollo 11 samples the moon was thought by many to be a primitive undifferentiated body e g urey 1966 a concept shattered by the data returned from the apollo and luna missions ever since new data have helped to address some of our questions but of course they also produced new questions in this chapter we provide a summary of knowledge about lunar geologic processes and we describe major scientific advancements of the last decade that are mainly related to the most recent lunar missions such as galileo clementine and lunar prospector 1 1 the moon in the planetary context compared to terrestrial planets the moon is unique in terms of its bulk density its size and its origin fig 1 1a c all of which have profound effects on its thermal evolution and the formation of a secondary crust fig 1 1d numerous planetary scientists considered the moon as an endmember among the planetary bodies in our solar system because its lithosphere has been relatively cool rigid and intact throughout most of geological time a one plate planet and its surface has not been affected by plate recycling an atmosphere water or life therefore the moon recorded and preserved evidence for geologic processes that were active over the last 4 4 5 b y and offers us the unique opportunity to look back into geologic times for which evidence on earth has long been erased fig 1 1c d impact cratering an exterior process is considered the most important surface process on the moon internal

shallow moonquakes and large shallow earthquakes a temporal correlation abstract the structure and seismicity of the moon is very different from that of the earth one point of similarity is that statistics of seismic energy release in both bodies are dominated by the largest shallow focus events this study presents evidence of a relationship linking the timing of the 28 known shallow moonquakes with the timing of the 26 largest shallow earthquakes occurring in the same years 1971 1976 distributions of the geocentric ecliptic longitude of the moon m for the time of occurrence of the lunar and terrestrial seismic events were analyzed both separately and in combination for the entire 6 year period and for individual years with the following results 1 statistically significant clustering is present in the series of m for the times of the earthquakes and moonquakes for the entire sample period random probability 0 0036 and for 2 of the 6 individual years random probabilities 0 02 2 phases of the separate lunar and terrestrial seismic event m distributions for the 6 year period differ by less than 7 phases of the earthquake and moonquake distributions are found in the same quadrant of the range in 5 of the 6 individual years 3 annual levels of shallow focus seismic activity in the earth and moon vary in concert in the years 1971 1976

the longevity of lunar volcanism implications of thermal evolution calculations with 2d and 3d mantle convection models abstract lunar volcanism as is generally accepted started well before the emplacement of the mare fill at 3 1 3 9 ga b p and likely extended well into the eratosthenian 3 1 1 1 ga b p the early volcanism is relatively easily understood the extension of the activity to possibly 1 5 ga b p albeit at a decreasing rate poses a problem since a relatively small body such as the moon may be expected to cool rapidly and freeze a partially molten mantle layer quickly we present thermal history models in which a region of partial melt forms in the mantle underneath the lithosphere almost immediately after the start of the model at depths between 300 and 700 km depending on the chosen initial depth of the magma ocean to calculate the thermal histories we use axisymmetric 2d and fully 3d spherical shell convection codes with viscosity depending on the azimuthally averaged temperature the thermal evolution of the moon is found to be characterized by the growth of a massive 700 to 800 km thick lithosphere while the lower mantle and core cool only by 100 200 k the partial melt zone decreases in thickness with time from top to bottom until it vanishes at times between 3 4 and 2 2 ga b p the maximum degree of partial melting is between roughly 10 and 20 the partial melt layer is initially global and is disrupted by cold downwellings as cooling proceeds the melt zone freezes from above due to the thickening of the lithosphere which implies that the source region of volcanic rock proceeds to increasing depth with time this corresponds nicely with the variation of titanium with age of lunar mare basalts mixing of the melt zone with the underlying mantle chemically rejuvenates the melt zone to some degree and thus the source region of the mare basalts

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

origin and consequences of cyclic ice rafting in the northeast atlantic ocean during the past 130 000 years deep sea sediment cores recovered from the northeast atlantic ocean were examined in order to elucidate the influence of the earth s orbital parameters on major ice rafting analyses of coarse grained ice rafted debris and planktonic foraminifers revealed a strong reaction to the precession signal since 130 000 yr b p dropstone layers have been deposited each half period of a precessional cycle 11 000 1000 yr ice rafting occurs during times of winter minimum summer maximum insolation and summer minimum winter maximum insolation in the first case high summer insolation forces meltwater discharge from the ice sheets into the polar seas which subsequently enhances formation of sea ice during the winter in the second case growth of continental ice enhances iceberg production which also leads to a salinity reduction of surface seawater both situations result in a southward penetration of polar water thus the marine record of dropstones documents ice rafting not only during weichselian stades but also during cold events within interstades the regularity of ice rafting yields a useful framework to calibrate and elucidate climatic changes not only in the region of the north atlantic ocean but also in remote areas such as the pacific ocean and the antarctic

high stress shallow moonquakes evidence for an initially totally molten moon abstract thermoelastic stress calculations show that if the moon was initially molten only in the outer few hundred kilometers as in the magma ocean model of the moon the highlands crust should be aseismic in contrast if the moon was initially totally molten high stress 1 to 3 kbar shallow 0 to 6 km deep compressional moonquakes should be occurring in the highlands crust calculations of the minimum stress drops made for the 28 observed shallow moonquakes suggest that 3 of them probably have stress drops in the kbar range thus these very limited seismic data are consistent with the model that the moon was initially totally molten

a mechanism for the generation of the lunar mare basalts summary according to the magma ocean or magmasphere model of lunar formation rapid accretion would result in the formation of a solid primitive core of undifferentiated material surrounded by a spherical shell of molten silicate as the outer layers of the moon cool by radiation of heat to space the deep interior will warm due to the decay of trace radionuclides this will lead to compression of the remnant magmasphere producing excess pressure in the fluid magma it is proposed that relief of this excess pressure through vents opened by the excavation of the mascon basins was sufficient to drive the major episodes of mare volcanism between 3 9 3 2 ga thermal models of the moon are constructed and a range of initial conditions based on the magmasphere model are identified which satisfy known constraints on lunar evolution the rate at which radial thermoelastic stress accumulates within the moon is calculated and from this estimates of the maximum volume of basaltic magma which could be produced by this mechanism are obtained by comparing these calculated magma generation rates with estimates of the volume of mare basalts residing on the lunar surface we are able to identify a set of initial temperature profiles which both satisfy the known constraints on lunar evolution and are able to produce the observed volume of mare basalts these models are characterised by deep magmaspheres and or initially warm central temperatures

last interglacial and holocene altithermal environments in south africa and namibia micromammalian evidence abstract climatic interpretations are derived indirectly from evidence for vegetation changes based on the remains of micromammals small rodents and shrews from archaeological sites thus far only border cave has provided evidence apparently referable to the earlier altithermal in oxygen isotope substage 5e vegetation zones and by implication climatic zones apparently extended 3 and more south of their present southern limits rainfall may have been up to 100 more than it is today and much more seasonal with drier winters mean annual temperatures were perhaps about 1 c higher on other evidence eight other sites provide evidence concerning conditions during the holocene altithermal 7000 6000 yr b p the evidence seems to indicate relatively low annual precipitation in the main summer rainfall region and an extended rainfall season in the southwestern winter rainfall region it is less clear whether or not annual rainfall was relatively high at this time in the latter region although in the namib desert conditions were apparently wetter this tends to agree with the dry period analogue of cockcroft et al 1987 and would imply reduced seasonality of precipitation throughout the region in contrast to the situation during the earlier altithermal apparent conflict with palynological evidence may be explainable but requires further examination

effects of lunar cumulate mantle overturn and megaregolith on the expansion and contraction history of the moon 1 gravity anomalies derived from recent gravity recovery and interior laboratory data suggest the presence of early volume expansion of the moon the absence of identifiable thrust faults limits the total net contraction that has occurred these observations provide constraints on the lunar thermal evolution which raise questions for giant impact origin of the moon to study the lunar expansion contraction history we perform 3 d thermochemical mantle evolution models with solidifying core overlain by a layer of ilmenite bearing cumulates ibcs resulting from mantle overturn after magma ocean solidification our models focus on the effects of the overturn produced density stratification with a deep heat producing element hpe distribution and a top insulating megaregolith layer the deep hpe can cause an early expansion up to 1 5 km radius due to the heating of thedeep mantle this hpe distribution also reduces the present day contraction by 7 km compared to the models without overturn an end member model with a stable ibc rich layer on the core mantle boundary shows an overall present day contraction as small as 1 1 km the low thermal conductivity of megaregolith also affects the present day contraction reducing it by 3 km

earthquake prediction a new physical basis summary subcritical crack growth in the laboratory occurs slowly but progressively in solids subjected to low stresses at low strain rates the cracks tend to grow parallel to the maximum compressive stress so that when this stress is aligned over a large enough region the cracks will also be aligned and possess effective seismic anisotropy it is suggested that such subcritical crack growth produces extensive dilatancy anisotropy eda throughout earthquake preparation zones this process is a possible driving mechanism for earthquake precursors observed at substantial distances from impending focal zones and provides in the shear wave splitting which has been observed in several seismic regions a possible technique for monitoring the build up of stress before earthquakes

size variation in tachyoryctes splendens east african mole rat and its implications for late quaternary temperature change in equatorial east africa abstract this study develops a new proxy for quaternary temperature change in tropical africa through analysis of size variation in east african mole rat tachyoryctes splendens in modern mole rats mandibular alveolar length is unrelated to annual precipitation precipitation seasonality temperature seasonality or primary productivity however it is inversely correlated with mean annual temperature in agreement with bergmann s rule this relationship is observed at temperatures below 17 3 c but not at higher temperatures we apply these observations to late quaternary mole rats from wakondo 100 ka and kisaaka 50 ka in the lake victoria region and enkapune ya muto eym 7 2 3 2 ka in kenya s central rift the lake victoria mole rats are larger than expected for populations from warm climates typical of the area today implying cooler temperatures in the past the magnitude of temperature decline needed to drive the size shift is substantial 4 6 c similar in magnitude to the degree of change between the last glacial maximum and holocene but is consistent with regional temperature records and with scenarios linking equatorial african temperature to northern hemisphere summer insolation size changes through time at eym indicate that rising temperatures during the middle holocene accompanied and potentially contributed to a decline in lake naivasha and expansion of grassland vegetation

the influence of tidal stresses on deep moonquake activity abstract over the period 1970 1977 the apollo seismic network detected many deep moonquakes from relatively few discrete hypocentres on the near side of the moon the occurrence times of moonquakes from each hypocentre showed tidal periodicities by calculating the tidal stress variations in five hypothesized spherically symmetric models of the moon and comparing with a homogeneous model we have investigated the influence of tidal stresses on deep moonquakes for a variety of lunar models the phases of the calculated temporal variations in tidal stresses were found to be independent of the model unfortunately this means that moonquake occurrence times cannot be used to place constraints on radial variations in lunar structure the results of this analysis contribute to our understanding of the causes of deep moonquake activity which are briefly reviewed the focal mechanisms of events at the most active hypocentres change with time nevertheless it seems unlikely that deep moonquakes are caused by the release of tidal strain energy alone at such a large lithostatic confining stress the tidal stresses must be superimposed on much larger secular stresses and the most plausible mechanism that might give rise to such secular stresses seems to be thermal contraction

pollen analysis of hyena coprolites and sediments from equus cave taung southern kalahari south africa equus cave in quaternary tufa near taung in the semiarid woodland of the southern kalahari yielded 2 5 m of sediment in which a rich assemblage of bones and coprolites was preserved the fossils were accumulated mainly by hyenas during the late pleistocene and holocene pollen from coprolites reflects diet as well as vegetation over relatively large areas visited by hyenas while pollen from sediments represents more local sources the pollen sequence derived from coprolites and sediments demonstrates how the vegetation evolved from open grassland with small shrubs and occasional trees during the late pleistocene to open savanna with more small shurbs then during the last 7500 yr to modern savanna temperatures were not more than 4 c cooler and it was slightly moister than today during the late pleistocene phase it became gradually warmer but relatively dry before optimal temperature and moisture conditions developed around 7500 yr b p climatic conditions slightly less favorable for woodland occurred during part of the late holocene

environmental ecological and paleoanthropological implications of the late pleistocene mammalian fauna from equus cave northern cape province south africa abstract the late pleistocene deposits of equus cave northern cape province south africa have provided more than 30 000 taxonomically identifiable mammal bones from 48 species context associations and features of the bone assemblage implicate brown hyenas as the main accumulators the fauna is significant mainly because 1 it supplements previous evidence that regional climate was cooler and possibly also somewhat moister during part s of the late pleistocene but deviated less from the historic norm than in areas farther south 2 it shows that bond s springbok which became extinct in the early holocene differed from the surviving common springbok not only in important morphological respects but also in reproductive pattern and 3 it sustains earlier suggestions that an abundance of carnivores a paucity of small hard bones and increase in the cranial postcranial ratio with species size and exclusively attritional mortality profiles are features that tend to differentiate assemblages accumulated by brown hyenas from those accumulated by people in addition pending firmer dating the fragmentary human fossils from equus cave may support an exclusively african origin for anatomically modern humans

recurring dynamically induced thinning during 1985 to 2010 on upernavik isstrom west greenland this is the publisher s version also available electronically from http onlinelibrary wiley com

shallow seismic activity and young thrust faults on the moon the discovery of young thrust faults on the moon is evidence of recent tectonic activity but how recent is unknown seismometers at four apollo landing sites recorded 28 shallow moonquakes between 1969 and 1977 some of these shallow quakes could be associated with activity on the young faults however the epicentre locations of these quakes are poorly constrained here we present more accurate estimates of the epicentre locations based on an algorithm for sparse seismic networks we found that the epicentres of eight near surface quakes fall within 30 km of a fault scarp the distance of the expected strong ground shaking from an analysis of the timing of these eight events we found that six occurred when the moon was less than 15 000 km from the apogee distance analytical modelling of tidal forces that contribute to the current lunar stress state indicates that seven near apogee events within 60 km of a fault scarp occur at or near the time of peak compressional stresses when fault slip events are most likely we conclude that the proximity of moonquakes to the young thrust faults together with evidence of regolith disturbance and boulder movements on and near the fault scarps strongly suggest the moon is tectonically active shallow moonquakes detected at four apollo landing sites between 1969 and 1977 occurred during maximum stress and in close proximity to young faults suggesting that the moon is tectonically active according to reanalyses of the seismic data and tidal force modelling

the constitution and structure of the lunar interior the current state of understanding of the lunar interior is the sum of nearly four decades of work and a range of exploration programs spanning that same time period missions of the 1960s including the rangers surveyors and lunar orbiters as well as earth based telescopic studies laid the groundwork for the apollo program and provided a basic understanding of the surface its stratigraphy and chronology through a combination of remote sensing surface exploration and sample return the apollo missions provided a general picture of the lunar interior and spawned the concept of the lunar magma ocean in particular the discovery of anorthite clasts in the returned samples led to the view that a large portion of the moon was initially molten and that crystallization of this magma ocean gave rise to mafic cumulates that make up the mantle and plagioclase flotation cumulates that make up the crust smith et al 1970 wood et al 1970 this model is now generally accepted and is the framework that unifies our knowledge of the structure and composition of the moon the intention of this chapter is to review the major advances that have been made over the past decade regarding the constitution of the moon s interior much of this new knowledge is a direct result of data acquired from the successful clementine and lunar prospector missions as well as the analysis of new lunar meteorites as will be seen results from these studies have led to many fundamental amendments to the magma ocean model much of what we know from sample analyses has been previously summarized elsewhere and only their most important aspects will be discussed in this chapter the reader is referred to the relevant chapters in the books basaltic volcanism on the terrestrial planets basaltic volcanism study project 1981 the

subsurface iceberg melt key to greenland fjord freshwater budget liquid freshwater fluxes from the greenland ice sheet affect ocean water properties and circulation on local regional and basin wide scales with associated biosphere effects the exact impact however depends on the volume timing and location of freshwater releases which are poorly known in particular the transformation of icebergs which make up roughly 30 50 of the loss of the ice sheet mass to liquid freshwater is not well understood here we estimate the spatial and temporal distribution of the freshwater flux for the helheim sermilik glacier fjord system in southeast greenland using an iceberg melt model that resolves the subsurface iceberg melt by estimating seasonal variations in all the freshwater sources we confirm quantitatively that iceberg melt is the largest annual freshwater source in this system type we also show that 68 78 of the iceberg melt is released below a depth of 20 m and seasonally about 40 100 of that melt is likely to remain at depth in contrast with the usual model assumptions iceberg melt also peaks two months after all the other freshwater sources peak our methods provide a framework to assess individual freshwater sources in any tidewater system and our results are particularly applicable to coastal regions with a high solid ice discharge in greenland iceberg melt is the largest annual freshwater source in a south greenland fjord with release largely below 20 m depth according to iceberg model simulations furthermore iceberg melt peaks later in the year than other sources of freshwater

north atlantic warming and the retreat of greenland s outlet glaciers mass loss from the greenland ice sheet quadrupled over the past two decades contributing a quarter of the observed global sea level rise increased submarine melting is thought to have triggered the retreat of greenland s outlet glaciers which is partly responsible for the ice loss however the chain of events and physical processes remain elusive recent evidence suggests that an anomalous inflow of subtropical waters driven by atmospheric changes multidecadal natural ocean variability and a long term increase in the north atlantic s upper ocean heat content since the 1950s all contributed to a warming of the subpolar north atlantic this led in conjunction with increased runoff to enhanced submarine glacier melting future climate projections raise the potential for continued increases in warming and ice mass loss with implications for sea level and climate

glacier and ocean variability in ata sund west greenland since 1400 ce to improve knowledge of marine terminating glaciers in western greenland marine sediment cores from the ata sund fjord system hosting two outlet glaciers eqip sermia and kangilerngata sermia were investigated the main objective was to reconstruct glacial activity and paleoceanographic conditions during the past 600 years ice rafted debris ird was quantified by wet sieving sediment samples and by using a computed tomography scan variability in relative bottom water temperatures in the fjord was reconstructed using foraminiferal analysis on the basis of this three periods of distinct glacial regimes were identified period 1 1380 1810 ce which covers the culmination of the little ice age lia and is interpreted as having advanced glaciers with high ird content period 2 1810 1920 ce the end of the lia which was characterised by a lowering of the glaciers calving flux in response to climate cooling during period 3 1920 2014 ce both glaciers retreated substantially to their present day extent the bottom water temperature started to decrease just before period 2 and remained relatively low until just before the end of period 3 this is interpreted as a local response to increased glacial meltwater input our study was compared with a study in disko bay nearby jakobshavn glacier and the result shows that both of these greenlandic marine terminating glaciers are responding to large scale climate change however the specific imprint on the glaciers and the different fjord waters in front of them result in contrasting glacial responses and sediment archives in their respective fjords

lunar solar periodicities of large earthquakes in southern california large earthquakes in southern california with epicentres between 33 and 36 n have statistically significant 12 hourly lunar fortnightly and 18 6 yr periodicities smaller earthquakes in the same region do not display these periodicities a search for tidal effects associated with these periodicities shows that large earthquakes have significant correlations with the times and orientations of daily semi daily tidal stresses while the lunar fornightly term is associated with the ocean tides along the southern californian coast

identification of new events in apollo 16 lunar seismic data by hidden markov model based event detection and classification detection and identification of interesting events in single station seismic data with little prior knowledge and under tight time constraints is a typical scenario in planetary seismology the apollo lunar seismic data with the only confirmed events recorded on any extraterrestrial body yet provide a valuable test case here we present the application of a stochastic event detector and classifier to the data of station apollo 16 based on a single waveform example for each event class and some hours of background noise the system is trained to recognize deep moonquakes impacts and shallow moonquakes and performs reliably over three years of data the algorithm s demonstrated ability to detect rare events and flag previously undefined signal classes as new event types is of particular interest in the analysis of the first seismic recordings from a completely new environment we are able to classify more than 50 of previously unclassified lunar events and additionally find over 200 new events not listed in the current lunar event catalog these events include deep moonquakes as well as impacts and could be used to update studies on temporal variations in event rate or deep moonquakes stacks used in phase picking for localization no unambiguous new shallow moonquake was detected but application to data of the other apollo stations has the potential for additional new discoveries 40 years after the data were recorded besides the classification system could be useful for future seismometer missions to other planets e g the insight mission to mars

carnivore size and quaternary climatic change in southern africa abstract the relationship between carnassial length and latitude south is analyzed for 17 african carnivore species to determine if individuals tend to be larger in cooler climates as predicted by bergmann s rule with modern data in support middle and late quaternary temperatures might then be inferred from mean carnassial length in fossil samples such as those from equus cave elandsfontein sea harvest duinefontein and swartklip in the cape province of south africa one problematic aspect of the study is the use of carnassial length and latitude as necessary but imperfect substitutes for body size and temperature respectively for some species another difficulty is the relatively small number of available modern specimens combined with their uneven latitudinal spread still in 14 of the species carnassial length does tend to increase with latitude south while mean carnassial length in the same species tends to be greater in those fossil samples which accumulated under relatively cool conditions as inferred from sedimentologic palynological or geochemical data given larger modern samples from a wide variety of latitudes refinement of the mathematical relationship between carnassial length and latitude in various species may even permit quantitative estimates of past temperatures in southern africa

constraints on deep moonquake focal mechanisms through analyses of tidal stress 1 a relationship between deep moonquake occurrence and tidal forcing is suggested by the monthly periodicities observed in the occurrence times of events recorded by the apollo passive seismic experiment in addition the typically large s wave to p wave arrival amplitude ratios observed on deep moonquake seismograms are indicative of shear failure tidal stress induced in the lunar interior by the gravitational influence of the earth may influence moonquake activity we investigate the relationship between tidal stress and deep moonquake occurrence by searching for a linear combination of the normal and shear components of tidal stress that best approximates a constant value when evaluated at the times of moonquakes from 39 different moonquake clusters we perform a grid search at each cluster location computing the stresses resolved onto a suite of possible failure planes to obtain the best fitting fault orientation at each location we find that while linear combinations of stresses and in some cases stress rates can fit moonquake occurrence at many clusters quite well for other clusters the fit is not strongly dependent on plane orientation this suggests that deep moonquakes may occur in response to factors other than or in addition to tidal stress several of our inferences support the hypothesis that deep moonquakes might be related to transformational faulting in which shear failure is induced by mineral phase changes at depth the occurrence of this process would have important implications for the lunar interior

tidal triggering of earthquakes analysis of the tidal stress tensor at the time of moderate to large earthquakes strongly suggests that shallow 30 km larger magnitude oblique slip and dip slip earthquakes are triggered by tidal stresses no corresponding triggering effect is seen for shallow strike slip earthquakes or for any type of intermediate or deep focus earthquakes which have been studied tidal triggering is also discussed from the viewpoint of the dilatancy diffusion model specifically the model as usually stated excludes the possibility of small earthquakes being tidally triggered

on the ratio of the mixing coefficients of heat and salt of antarctic bottom water in the north atlantic values of vertical eddy salt diffusivity and heat diffusivity for antarctic bottom water were estimated by whitehead and worthington 1982 from both current meter results and geostrophic calculations the ratios of the diffusivities have one impossible value of 0 858 for water colder than 1 1 c potential temperature for the geostrophic results this could be evidence against the geostrophic results however a small interpolation error in their tables 5 and 6 was uncovered the corrected ratio is 1 01 which is possible although very close to 1 and one other ratio is 0 98 thus geostrophic calculations cannot be ruled out but they lead to ratios very close to 1

ice stream stability on a reverse bed slope marine ice streams whose beds deepen inland are thought to be inherently unstable numerical modelling of the maguerite bay ice stream retreat in west antarctica since the last glacial maximum suggests that an ice stream can stabilize on an inland sloping bed owing to increased lateral drag where the ice stream narrows marine based ice streams whose beds deepen inland are thought to be inherently unstable1 2 3 this instability is of particular concern because significant portions of the marine based west antarctic and greenland ice sheets are losing mass and their retreat could contribute significantly to future sea level rise4 5 6 7 however the present understanding of ice stream stability is limited by observational records that are too short to resolve multi decadal to millennial scale behaviour or to validate numerical models8 here we present a dynamic numerical simulation of antarctic ice stream retreat since the last glacial maximum lgm constrained by geophysical data whose behaviour is consistent with the geomorphological record we find that retreat of marguerite bay ice stream following the lgm was highly nonlinear and was interrupted by stabilizations on a reverse sloping bed where theory predicts rapid unstable retreat we demonstrate that these transient stabilizations were caused by enhanced lateral drag as the ice stream narrowed we conclude that as well as bed topography ice stream width and long term retreat history are crucial for understanding decadal to centennial scale ice stream behaviour and marine ice sheet vulnerability

a 2000 year record of ocean influence on jakobshavn isbrae calving activity based on marine sediment cores the greenland ice sheet has experienced significant mass loss in recent years a substantial component of this is attributable to the retreat of marine terminating outlet glaciers which lose mass

changes during the holocene in the size of white tailed deer odocoileus virginianus from central illinois abstract white tailed deer odocoileus virginianus from central illinois varied in size during the holocene the record which extends back to 8450 yr b p indicates small deer through the mid holocene until 3650 yr b p after which size increases although influences of winter climate seasonality anthropogenic effects and other ecological factors should not be discounted an intriguing possible cause of the deer size shifts is insolation driven summer climate and its influence on food resources in the holocene small deer size is correlated with high summer insolation and with low winter insolation climatic models indicate that in spite of changes in insolation holocene winters did not vary greatly through time especially in contrast to summers which were dynamic physiological constraints peculiar to o virginianus make critical the quality of summer forage for determining final adult size summer temperature averaged 2 c warmer than present during the middle holocene which increased evaporation and probably reduced the period of availability of high quality forage low in fiber and high in protein consequently less fuel for growth was consumed by mid holocene deer and only small body size was achieved other possible causes e g bergmann s rule seasonality of clinal variation are considered with reference to central illinois deer but at present the most parsimonious explanation appears to be the summer insolation hypothesis

beginning and end of lunar mare volcanism mare volcanism on the moon is commonly attributed to an important but relatively short lived epoch of internal heating after 3 900 myr bp but before about 2 500 myr bp refs 1 2 although some studies suggested that mare volcanism had started earlier3 5 than times indicated by dated lunar samples only recently have photogeological spectral and geochemical data6 8 documented the importance of a pre 4 000 myr bp epoch similarly early earth based geological mapping revealed a bright rayed crater lichtenberg superposed by mare units9 thereby indicating that mare volcanism must have extended to times significantly more recent than 3 100 myr bp lunar orbital photography confirmed this inferred strati graphical relationship10 but crater statistics indicated that the youngest units were at least twice the age of copernicus or between 1 700 and 2 000 myr bp refs 11 13 we present here the inferred distribution and style of the early phases of mare volcanism based on current evidence and conclude that certain regions of the moon underwent two distinct pulses of igneous activity we then examine crater statistics for the post lichtenberg mare unit and other selected units and conclude that mare volcanism extended to a time comparable with that of the copernicus impact or 1 myr bp these reassessments of the oldest and youngest maria provide new constraints on geophysical models of the internal thermal history of the moon

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

the origin of massive diamicton facies by iceberg rafting and scouring scoresby sund east greenland almost 90 of 39 m of core material recovered from scoresby sund and the adjacent east greenland shelf is massive diamicton interpreted to be formed predominantly by the release of iceberg rafted debris and reworking by iceberg scouring there is also likely to be a contribution from suspension settling of fines derived from glaciofluvial sources model calculations suggest that the 14c derived holocene sedimentation rate of 0 1 0 3 m 1000 yr 1 in scoresby sund can be accounted for mainly by iceberg rafting of debris a further 4 of core material is of gravel or coarse sand lenses interpreted to reflect iceberg dumping of debris intensive iceberg scouring which reworks sea floor sediments is observed on acoustic records from over 30 000 km2 of the scoresby sund fiord system and the adjacent east greenland shelf 69 72 n and 75 n the rate of iceberg production from greenland ice sheet outlet glaciers and iceberg drift tracks on the shelf suggests that iceberg rafting and scouring may be important over a significant proportion of the 500 000 km2 area above the shelf break the relatively extensive modern occurrence of massive diamicton formed by iceberg rafting and scouring together with suspension settling of fines suggests that it may also be a significant facies in the glacier influenced geological record the recognition in the geological record of the massive diamicton facies described above may also indicate the former presence of fast flowing ice sheet outlet glaciers

aerial photographs reveal late 20th century dynamic ice loss in northwestern greenland global warming is predicted to have a profound impact on the greenland ice sheet and its contribution to global sea level rise recent mass loss in the northwest of greenland has been substantial using aerial photographs we produced digital elevation models and extended the time record of recent observed marginal dynamic thinning back to the mid 1980s we reveal two independent dynamic ice loss events on the northwestern greenland ice sheet margin from 1985 to 1993 and 2005 to 2010 which were separated by limited mass changes our results suggest that the ice mass changes in this sector were primarily caused by short lived dynamic ice loss events rather than changes in the surface mass balance this finding challenges predictions about the future response of the greenland ice sheet to increasing global temperatures

evaluation of deep moonquake source parameters implication for fault characteristics and thermal state while deep moonquakes are seismic events commonly observed on the moon their source mechanism is still unexplained the two main issues are poorly constrained source parameters and incompatibilities between the thermal profiles suggested by many studies and the apparent need for brittle properties at these depths in this study we reinvestigated the deep moonquake data to reestimate its source parameters and uncover the characteristics of deep moonquake faults that differ from those on earth we first improve the estimation of source parameters through spectral analysis using new broadband seismic records made by combining those of the apollo long and short period seismometers we use the broader frequency band of the combined spectra to estimate corner frequencies and dc values of spectra which are important parameters to constrain the source parameters we further use the spectral features to estimate seismic moments and stress drops for more than 100 deep moonquake events from three different source regions this study revealed that deep moonquake faults are extremely smooth compared to terrestrial faults second we reevaluate the brittle ductile transition temperature that is consistent with the obtained source parameters we show that the source parameters imply that the tidal stress is the main source of the stress glut causing deep moonquakes and the large strain rate from tides makes the brittle ductile transition temperature higher higher transition temperatures open a new possibility to construct a thermal model that is consistent with deep moonquake occurrence and pressure condition and thereby improve our understandings of the deep moonquake source mechanism

palynological analysis of hyrax middens from southern africa abstract hyrax middens in relatively dry parts of africa preserve plant material which includes pollen the bottoms of two stratified hyrax dung middens from blydefontein basin in the karoo shrubland of south africa were dated by radiocarbon to ca 300 yr b p and ca 1130 yr b p comparison of midden pollen spectra with pollen from alluvial sediments near one of the hyrax middens and in modern surface samples indicates that middens contain pollen which reflects local vegetation and that diet probably does not have a major influence on pollen spectra changes in pollen composition probably reflect climatic conditions during the early history of the older midden profile grass dominated spectra suggest moist conditions existed between 1200 and 300 yr b p and an interval of slightly more shrubby karoid vegetation possibly points to a minor dry spell at 1000 yr b p a sharp increase of karoid shrub vegetation and a decrease of grass since 300 yr b p is reflected in both middens the change was apparently triggered by relatively dry conditions and later during the last 150 years it was enhanced by overgrazing from european domestic stock

lunar multiring basins and the cratering process abstract numerous studies of the lunar gravity field have concluded that the lunar moho is substantially uplifted beneath the young multiring basins this uplift is presumably due to the excavation of large quantities of crustal material during the cratering process and subsequent rebound of the impact basin floor using a new dual layered crustal thickness model of the moon the excavation cavities of some nearside multiring basins grimaldi and larger and younger than tranquillitatis were reconstructed by restoring the uplifted moho to its preimpact location the farside south pole aitken spa basin was also considered due to its importance in deciphering lunar evolution restoring the moho to its preimpact position beneath these basins resulted in a roughly parabolic depression from which the depth and diameter of the excavation cavity could be determined using these reconstructed excavation cavities the basin forming process was investigated excavation cavity diameters were generally found to be on the small side of most previous estimates for orientale the modeled excavation cavity lies within the inner rook ring additionally with the exception of the three largest basins serenitatis imbrium and south pole aitken the depth diameter ratios of the excavation cavities were found to be 0 115 0 005 a value consistent with theoretical and experimental results for impact craters orders of magnitude smaller in size the three largest basins however appear to have significantly shallower depths of excavation compared to this trend it is possible that this may reflect a different physical process of crater formation e g nonproportional scaling special impact conditions or postimpact modification processes the crustal thickness model also shows that each basin is surrounded by an annulus of thickened crust we interpret this thickened crust as representing thick basin ejecta deposits and we show that the radial variation in the thickness of these deposits is consistent with scaling laws obtained from small scale experimental studies if multiring basins ever possessed a terraced main crater rim this terraced zone may be presently unrecognizable at the surface due to the emplacement of ejecta deposits that exceed a few kilometers in thickness exterior to the excavation cavity rim we also show that the interiors of many basins were superisostatic before mare volcanism commenced those basins that were closest to approaching a premare isostatic state lie close to or within an anomalous geochemical province rich in heat producing elements

size variation in the cape dune molerat bathyergus suillus and late quaternary climatic change in the southwestern cape province south africa abstract within their historic range at the southwestern tip of africa cape dune molerats bathyergus suillus tend to be significantly larger in areas of higher rainfall they also tend to be large in late quaternary fossil samples associated with independent evidence for relatively moist climate and small in samples associated with evidence for relatively dry conditions together with sedimentologic geomorphic and other faunal observations fluctuations in fossil dune molerat size imply that the regional climate was very moist during an early late quaternary interval corresponding to marine isotope stage 4 74 000 to 59 000 yr b p or perhaps to substage 5b or 5d centered on 110 000 and 90 000 yr b p respectively it was comparably moist again from roughly 14 000 to 8 000 yr b p somewhat drier than at present from about 8000 until 4000 yr b p and mainly near the modern average after 4000 yr b p together the modern and fossil data suggest that dune molerat size is a reliable index of past precipitation but it may not be useful for revealing extremely arid conditions because these seem to be associated with depositional occupational gaps in most local paleontological archeological sites

the physical mechanisms of deep moonquakes and intermediate depth earthquakes how similar and how different abstract we here review the characteristics of deep moonquakes dmq and conclude that they share many common features with certain categories of intermediate depth earthquakes namely the pressure temperature conditions where they occur their occurrence in highly localized nests their tendency to occur repeatedly at the same or nearly the same location and their distribution of sizes b values we thus explore various physical mechanisms proposed for earthquakes that might also explain deep moonquakes these include the possibility that there are partial melts or fluid phases in the lunar mantle that permit dmq to occur at pressures where ordinary brittle fracture is not possible the possibility that stress concentration increases tidal stresses at certain locations where moonquakes occur repeatedly and the possibility that dmq occur at relatively low stresses because rock strength is lowered by a fatigue process induced by the repetitive application of tidal stresses the similarities between dmq and terrestrial earthquakes imply that research focusing on the properties of both phenomena may help us understand the physical origins of both

glacial interglacial size variation in fossil spotted hyenas crocuta crocuta from britain abstract the lower carnassial lengths of spotted hyenas crocuta crocuta in 12 late pleistocene samples from britain indicate that on average local hyenas of the last devensian glaciation were significantly larger than their last interglaciation ipswichian counterparts together with the tendency for spotted hyena carnassial length to increase with latitude in present day africa this suggests that spotted hyena body size is inversely related to temperature as predicted by bergmann s rule the implication is that spotted hyena carnassial length can be used as an independent gauge of pleistocene temperature variation though the combined african and british data imply that the relationship between carnassial length and temperature is curvilinear such that as temperature declines equal amounts of further decline produce progressively smaller increases in average carnassial length

increased mass loss and asynchronous behavior of marine terminating outlet glaciers at upernavik isstrom nw greenland in order to model and predict future behavior of marine terminating glaciers it is essential to understand the different factors that control a glaciers response to climate change here we present a detailed study of the asynchronous changes in dynamic behavior of four adjacent marine terminating glaciers at upernavik isstrom ui northwest greenland between 1992 and 2013 velocities were stable for all outlets at ui between 1992 and 2005 the northernmost glacier started to accelerate and thin in 2006 and continued to do so into 2011 after which time the velocities stabilized the second most northerly glacier started to accelerate and thin in 2009 and continued to do so until the last observations in 2013 dramatically increasing the area affected by dynamically induced thinning the southern glaciers show little change with the most southerly glacier undergoing slight retreat and deceleration between 1992 and 2013 these observations point out the fact that the ui glaciers are reacting to climate change on different timescales the asynchronous behavior of the four neighboring glaciers is explained in terms of the individual glaciers geometry and terminus position the northernmost glacier is believed to have had a floating tongue between 1985 and 2007 which disintegrated in 2007 2008 this release of back stress destabilized the glacier causing it to accelerate and thin rapidly we suggest that the ice tongue broke up due to ocean warming induced thinning in the late 1990s recent response on ui glaciers is found to be related to increased surface melt our investigations suggest that three out of the four main glaciers in the ui are likely to be in unstable positions and may have the potential to rapidly thin and accelerate and increase their contribution to sea level in the future

the strength of the lunar lithosphere a self gravitating elastic spherical thick shell model is used to derive the present state of the lateral variations of density and stress differences within the lunar lithosphere the model is allowed to deform under the load of an initial surface topography and internal density distribution such that the resulting deformed body gives rise to the observed surface topography and gravity specified by the spherical harmonics of degree up to 70 two main models are considered model a and model b with elastic lithospheres of thickness 300 and 210 km respectively model a displays density perturbations of generally less than 200 kg m3 within the crustal layers reducing rapidly to less than 20 kg m3 at the base of the lithosphere the density perturbations in model b are similar in the crust and marginally higher at the base of the lithosphere the major stress differences in the mantle are associated with the mascon basins and are found to reach maximums of 8 10 mpa within the lower lithosphere 150 270 km of model a and maximums of 12 16 mpa at 150 to 180 km depth for model b a moderate correlation exists between the modeled stress distributions and shallow moonquake epicenters however the overall results of this study imply that other remnant stresses due to processes other than density perturbations exist and play a critical role in the large shallow moonquakes

rapid response of helheim glacier in greenland to climate variability over the past century during the early 2000s the greenland ice sheet experienced the largest ice mass loss of the instrumental record 1 largely as a result of the acceleration thinning and retreat of large outlet glaciers in west and southeast greenland 2 5 the quasi simultaneous change in the glaciers suggests a common climate forcing increasing air 6 and ocean 7 8 temperatures have been indicated as potential triggers here we present a record of calving activity of helheim glacier east greenland that extends back to about ad 1890 based on an analysis of sedimentary deposits from sermilik fjord where helheim glacier terminates specifically we use the annual deposition of sand grains as a proxy for iceberg discharge our record reveals large fluctuations in calving rates but the present high rate was reproduced only in the 1930s a comparison with climate indices indicates that high calving activity coincides with a relatively strong influence of atlantic water and a lower influence of polar water on the shelf off greenland as well as with warm summers and the negative phase of the north atlantic oscillation our analysis provides evidence that helheim glacier responds to short term fluctuations of large scale oceanic and atmospheric conditions on timescales of 3 10 years the forcings behind the rapid increase in mass loss from the greenland ice sheet in the early 2000s ref 1 are still debated it is unclear whether the mass loss will continue in the near future and ifso atwhatrate theseuncertaintiesareaconsequenceofour limited understanding of mechanisms regulating ice sheet variability and the response of fast flowing outlet glaciers to climate variability in southeast greenland helheim glacier one of the regions largestglaciers thinned acceleratedandretreatedduringtheperiod 20032005

shell morphometry of seven limpet species from coastal shell middens in southern africa measurements of shell parts and features elements of marine limpets can be used to derive morphometric equations for estimating total shell lengths this is demonstrated for seven limpet species commonly found on the southern african coast the equations can be used to reconstruct whole shell lengths for highly fragmented limpet samples in prehistoric shell middens a linear regression model is based on measurements of all shell elements resulting in high coefficients of determination with excellent predictive power in most cases these morphometric equations would enable archaeologists to derive more metrical information from fragmentary archaeological material than was previously the case we also present a case study where morphometric equations of two limpet species are applied to an archaeological sample from the south african west coast for the purpose of investigating possible biases in limpet shell preservation we conclude that small whole limpet shells survive longer than the bigger ones in this particular case but that many more such case studies need to be conducted in order to fully understand differential preservation of southern african limpet shells in archaeological sites

widespread acceleration of tidewater glaciers on the antarctic peninsula over the last half century the antarctic peninsula ap has been among the most rapidly warming regions on earth this has led to increased summer snowmelt loss of ice shelves and retreat of 87 of marine and tidewater glacier fronts tidewater glacier flow is sensitive to changes in basal water supply and to thinning of the terminus and faster flow leads directly to sea level rise the flow rates of most ap tidewater glaciers have never been measured however and hence their dynamic response to the recent changes is unknown we present repeated flow rate measurements from over 300 glaciers on the ap west coast through nine summers from 1992 to 2005 we show that the flow rate increased by similar to 12 on average and that this trend is greater than the seasonal variability in flow rate we attribute this widespread acceleration trend not to meltwater enhanced lubrication or increased snowfall but to a dynamic response to frontal thinning we estimate that as a result the annual sea level contribution from this region has increased by 0 047 0 011 mm between 1993 and 2003 this contribution together with previous studies that assessed increased runoff from the area and acceleration of glaciers resulting from the removal of ice shelves implies a combined ap contribution of 0 16 0 06 mm yr 1 this is comparable to the contribution from alaskan glaciers and combined with estimated mass loss from west antarctica is probably large enough to outweigh mass gains in east antarctica and to make the total antarctic sea level contribution positive

last interglacial sea levels and coastal caves in the cape province south africa abstract the dating of the 6 to 8 m shoreline in southern africa as early pleistocene prompted a reassessment of evidence from archaeological cave sites on the south coast of the cape province which had suggested that this shoreline is of last interglacial age the successions in the caves at klasies river mouth and die kelders have been misinterpreted in fact they confirm a pre last interglacial age for this feature these sites together with herolds bay cave indicate that in southern africa the only last interglacial shoreline above present sea level is at about 4 m and that it dates from isotope substage 5e

three decades of dating recent sediments by fallout radionuclides a review this paper reviews the 210pb dating programme carried out at the university of liverpool over a period of three decades since its inception by frank oldfield in the mid 1970s the work at liverpool

remelting mechanisms for shallow source regions of mare basalts abstract two mechanisms are studied which could induce remelting at shallow depths within the moon a radioactive heating model in which remelting is the result of lateral variations of the heat source concentration emplaced by the end of the initial differentiation event and a thermal insulation model in which remelting is induced by lateral variations of near surface conductivity as a result of a high porosity ejecta blanket created by basin forming impacts the effects of these perturbations are studied by evaluating the thermal evolution of an otherwise radially symmetric lunar model the radioactive heating models predict extensive pre basin volcanism which would probably remove from the source region many of the heat producing elements potentially responsible for melting therefore localized high concentrations of heat producing elements emplaced early would most probably not be heat sources for the basin filling mare basalts however they are plausible heat sources for pre basin mare basalts the thermal insulation model predicts a delay of about 200 m y between impact and volcanism thermal insulation may also allow for the persistence of source regions for young basalts at shallow depths if greater basin ages are correct from 4 2 to 3 9 ga and most volcanism occurred between 3 8 and 3 6 ga then the thermal insulation model may explain the delay between impact and basin filling if the basins formed during a terminal cataclysmic event at about 3 9 ga then the earliest stages of basin filling at about 3 8 ga may have been a result of melting beneath the basin as a result of mantle uplift basin filling may have been characterized by a migration of the source region from beneath the basin to beneath the adjacent highlands cooling of the top 200 km beneath the basin after 200 m y because of its high surface conductivity is consistent with the mascon support requirement

hvsr passive seismic stratigraphy for the investigation of planetary volcanic analogues abstract this paper presents new results of the application of passive seismic surveys for the stratigraphic investigation of planetary volcanic analogues we tested hvsr horizontal to vertical spectral ratio surveys that seem particularly suitable for planetary subsurface exploration in order to exploit the potential of these surveys in stratigraphic applications hvsr surveys were undertaken at the tinguaton volcanic region lanzarote canary islands seismic noise measurements were collected during the pangaea x 2018 testing campaign which formed part of the european space agency s esa astronaut training program single station free field seismic noise data were collected along two orthogonal profiles one crossing the tinguaton volcano the other passing alongside the tinguaton caldera seismic stratigraphic sections obtained from the shear wave velocity constrained inversion of the main h v peaks provided the main impedance contrasts between layers and a bulk estimate of the shear wave velocity in the layers contour maps of the hvsr patterns were used to recognize and identify the main volcanic units such as scoria deposits and different basaltic lava flows geological structures such as a regional fault related to the volcanic vent source and morphological characteristics such as the tinguaton caldera this study also identified several pitfalls that may limit the accuracy of such investigations these include the multilayer setting of scoria deposits and partly of underlying basalts as well as the presence of very thin horizons or a very gradual increase in shear wave velocity our study also shows the topographic effect due to the volcano s sharp topography along crater rim is significant and results in severe artifacts in the data from our work it is clear that hvsr method is an effective method to support the investigation of planetary volcanic terrains on the moon and mars with similarly volcanic complex geological settings even where horizontal layering and the isotropic site response are not fully verified

scattering attenuation profile of the moon implications for shallow moonquakes and the structure of the megaregolith abstract we report measurements of the attenuation of short period seismic waves in the moon based on the quantitative analysis of envelope records of lunar quakes our dataset consists of waveforms corresponding to 62 events including artificial and natural impacts shallow moonquakes and deep moonquakes recorded by the four seismometers deployed during apollo missions 12 14 15 and 16 to quantify attenuation and distinguish between elastic scattering and inelastic absorption mechanisms we measure the time of arrival of the maximum of energy t max and the coda quality factor q c the former is controlled by both scattering and absorption while the latter is an excellent proxy for absorption consistent with the strong broadening of seismogram envelopes in the moon we employ diffusion theory in spherical geometry to model the propagation of seismic energy in depth dependent scattering and absorbing media to minimize the misfit between predicted and observed t max for deep moonquakes and impacts we employ a genetic algorithm and explore a large number of depth dependent attenuation models quantified by the scattering quality factor q sc or equivalently the wave diffusivity d and the absorption quality factor q i the scattering and absorption profiles that best fit the data display very strong scattering attenuation q sc 10 or equivalently very low wave diffusivity d 2 km2 s in the first 10 km of the moon these values correspond to the most heterogeneous regions on earth namely volcanic areas below this surficial layer the diffusivity rises very slowly up to a depth of approximately 80 km where q sc and d exhibit an abrupt increase of about one order of magnitude below 100 km depth q sc increases rapidly up to approximately 2000 at a depth of about 150 km a value similar to the one found in the earth s mantle by contrast the absorption quality factor on the moon q i 2400 is about one order or magnitude larger than on earth our results suggest the existence of an approximately 100 km thick megaregolith which is much larger than what was previously thought the rapid decrease of scattering attenuation below this depth is compatible with crack healing through viscoelastic mechanisms using our best attenuation model we invert for the depth of shallow moonquakes based on the observed variation of t max with epicentral distance on average they are found to originate from a depth of about 50 km 20 km which suggests that these earthquakes are caused by the failure of deep faults in the brittle part of the moon

size variation in the rock hyrax procavia capensis and late quaternary climatic change in south africa abstract the average adult size of the rock hyrax varies greatly across south africa regression analysis suggests that mean hyrax size is more closely linked to precipitation than to temperature probably because precipitation has a much greater impact on preferred hyrax food plants the relationship between mean size and precipitation is curvilinear such that size increases up to about 700 mm annum and declines thereafter this parallels a tendency for less palatable grasses to replace more palatable ones where rainfall exceeds 700 mm annum in conjunction with other indicators of past climate hyrax size variation can be used to reconstruct precipitation history near deeply stratified south african late quaternary sites including elands bay cave die kelders cave 1 and nelson bay cave

mass balance of the greenland ice sheet from 1958 to 2007 we combine estimates of the surface mass balance smb of the greenland ice sheet for years 1958 to 2007 with measurements of the temporal variability in ice discharge d to deduce the total ice sheet mass balance during that time period we find a robust correlation r2 0 83 between anomalies in smb and in d which we use to reconstruct a continuous series of total ice sheet mass balance we find that the ice sheet was losing 110 70 gt yr in the 1960s 30 50 gt yr or near balance in the 1970s 1980s and 97 47 gt yr in 1996 increasing rapidly to 267 38 gt yr in 2007 multi year variations in ice discharge themselves related to variations in smb cause 60 20 more variation in total mass balance smb and therefore dominate the ice sheet mass budget copyright 2008 by the american geophysical union

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

seismic velocity structure of the lunar mantle i have inverted the recently completed set of seismic arrival times from the apollo lunar seismic network to estimate the average seismic velocities in three sections of the lunar mantle two for the upper mantle and one for the middle mantle the method used is a variation of the linearized least squares inversion where the inversion is accomplished in steps the estimated average velocities in the upper mantle decrease from vp 7 74 km s and vs 4 49 km s in the section above 270 km depth to vp 7 46 km s and vs 4 25 km s in the section between 270 and 500 km depth confirming the earlier finding of negative gradients based on seismic amplitude variations the average velocities in the middle mantle between the depths of 500 km and 1000 km of vp 8 26 km s and vs 4 65 km s are significantly higher than those in the upper mantle contradicting earlier estimates based on more limited data the higher velocities may suggest initial melting of the moon down to at least 1000 km depth

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

laminated sediments in glacimarine environments diagnostic criteria for their interpretation abstract fine grained laminated deposits are often reported from contemporary and ancient glacimarine sedimentary sequences laminated glacimarine sediments form by a variety of processes including suspension settling from turbid overflow plumes turbidity current deposition and contour current activity subglacial deformation of pre existing sediments may also produce laminated deposits in the form of glacitectonite and deformation till the development of diagnostic criteria for genetic discrimination of laminated glacimarine sediments is important both for their correct interpretation in sedimentary sequences and also for the accurate reconstruction of former glacier extent and geometry as laminated sediments may form in subglacial ice proximal and ice distal environments this paper reviews the processes by which laminated glacimarine sediments form and their resulting sedimentology the aim is to provide a synthesis of diagnostic sedimentological criteria for laminated glacimarine deposits that will assist in the interpretation of such sediments in the geological record laminated sediments are genetically differentiated on the basis of sedimentary structures bedding contacts stratigraphic relationships and macrofaunal content bioturbation these attributes also facilitate discrimination between glacimarine and glacilacustrine rhythmites the paper concludes by discussing the glaciological significance of laminated glacimarine sediments in terms of glacier hydrology reconstructions of former ice dynamics and basal thermal regime