inversion for seismic slip rate history and distribution with stabilizing constraints application to the 1986 andreanof islands earthquake we develop and present a method of inverting seismograms including their absolute amplitudes to obtain the complete seismic slip time history and distribution using the method of linear programming a rectangular fault is discretized into cells and the source duration into time steps the inversion for the slip rate distribution on the fault as a function of time reduces to the solution of a system of linear equations the influence on the solution of constraining different source parameters such as the sign of the slip rate and the seismic moment is investigated it is found that the constraint of positiveness of slip rate and the constraint that the seismic moment determined from the solution should be close to that obtained from the centroid moment tensor cmt solution are very strong constraints and are essential to obtaining a physically reasonable solution since the inverse problem is unstable instead of presenting only one particular solution we examine several solutions equally well fitting the data for all practical purposes we find that when both constraints are applied the solution becomes quite stable the method is applied to a data set consisting of the vertical component of available digitally recorded teleseismic p waves at stations within a chosen distance window for the 1986 andreanof islands earthquake mw 8 0 the preferred solution is the one in which the slip rate is constrained to be positive and the moment is set to the cmt value the average rupture speed in the 90 km segment to the east of the hypocenter was 3 2 km s and in the 190 km section to the west was 2 km s the maximum slip in the area of large moment release to the west was 5 m and the maximum slip rate which occurs in the same place as the maximum slip was 6 5 m s the slip distribution on the fault shows a corrugated pattern with the long axis in the direction of the plate convergence rather than normal to the arc which was the slip vector direction for the earthquake with most of the slip occurring pn a region of the fault to the west of the rupture nucleation zone this region continued to slip for about 55 s the total source duration being about 80 s the results of this analysis suggest that the long term motion on this portion of the aleutian arc is indeed in the direction of plate convergence

finite faults and inverse theory with applications to the 1979 imperial valley earthquake abstract using a representation theorem from elastodynamics subsurface slip on a known fault is formulated as the solution to an inverse problem in which recorded surface ground motion is the data two methods of solution are presented the least squares method which minimizes the squared differences between theory and data and the constrained least squares method which simultaneously maintains a set of linear inequalities instabilities in the solution are effectively eliminated in both methods and the sensitivity of the solution to small changes in the data is quantitatively stated the inversion methodology is applied to 77 components of near field ground acceleration recorded during the 15 october 1979 imperial valley earthquake the faulting is constrained to propagate bilaterally away from the epicenter at an average velocity of 90 per cent of the shear wave speed on a vertical fault plane extending from the surface to 10 km depth inequality constraints are used to keep the faulting sequence physically reasonable by maintaining right lateral motion and positive slip velocity the preferred solution is stable and provides a good fit to the data it is also realistic and consistent with observed surface offsets and independent estimates of seismic moment

teleseismically recorded seismicity before and after the may 7 1986 andreanof islands alaska earthquake the may 7 1986 andreanof islands earthquake mw 8 0 is the largest event to have occurred in that section of the aleutian arc since the march 9 1957 aleutian islands earthquake mw 8 6 teleseismically well recorded earthquakes in the region of the 1986 earthquake are relocated with a plate model and with careful attention to the focal depths the data set is nearly complete for mb 4 7 between longitudes 172 w and 179 w for the period 1964 through april 1987 and provides a detailed description of the space time history of moderate size earthquakes in the region for that period additional insight is provided by source parameters which have been systematically determined for mw 5 earthquakes that occurred in the region since 1977 and by a modeling study of the spatial distribution of moment release on the mainshock fault plane a technically significant component of oblique convergence in the central aleutian arc results in its breakup into clockwiserotating and westward translating blocks the western part of the andreanof block is distinct from and stronger than flanking regions the greater strength of this block segment and strong coupling along the main thrust zone result in the accumulation of high levels of shear stress which give rise to great earthquakes near its eastern boundary the occurrence of the 1986 rupture only 29 years after the 1957 earthquake may indicate that in the central aleutians m 7 earthquakes ordinarily do represent the predominant mode of strain release segmentation of the main thrust zone into upper and lower planes is supported by spatial and temporal patterns of seismicity and by focal mechanism data this and other lines of evidence indicate a downdip increase in fault strength and possibly in heterogeneity within the main thrust zone in subduction zone environments aftershocks of the 1986 earthquake were bounded to the west by the andreanof block boundary adak canyon and to the east by an aseismic segment of the main thrust zone near the subducted extension of the amlia fracture zone the aftershock distribution was bounded to the south by a forearc shear zone and to the north by the base of the main thrust zone in the hawley ridge segment and by the downdip edge of the upper plane of the main thrust zone in the eastern segment aftershocks which occurred near the volcanic line at shallow crustal depths in the upper plate were triggered by the mainshock and manifest a partial decoupling of oblique slip in this region along a west striking right lateral fault with low shear strength aftershock clustering along the main thrust zone was very similar to the distribution of prior seismicity suggesting a continuation of long term processes and the existence of areas with distinct mechanical properties interconnecting regions of low seismicity during both the premainshock and aftershock periods coincided with areas of major moment release during the mainshock seismicity data prior to the 1986 mainshock gave few clues about the location of the mainshock nucleation point the mainshock size and its time of occurrence however a large part of the mainshock moment release did coincide with a zone of seismic quiescence monitored by the adak local seismograph network

relations among subduction parameters clues to the dynamics of the subduction process are found in the many measurable parameters of modern subduction zones based on a critical appraisal of the geophysical and geological literature 26 parameters are estimated for each of 39 modern subduction zones to isolate causal relationships among these parameters multivariate analysis is applied to this data set this analysis yields empirical quantitative relations that predict strain regime and strike slip faulting in the overriding plate maximum earthquake magnitude benioff zone length slab dip arc trench gap and maximum trench depth excellent correlation is found between length of the benioff zone and the product of convergence rate and age of the downgoing slab this relationship is consistent with the conductive heating model of molnar et al 1979 if the model is modified in one respect the rate of heating of the slab is not constant it is substantially slower during passage of the slab beneath the accretionary prism and overriding plate the structural style in the overriding plate is determined by its stress state though the stress state of overriding plates cannot be quantified one can classify each individual subduction zone into one of seven semiquantitative strain classes that form a continuum from strongly extensional class 1 back arc spreading to strongly compressional class 7 active folding and thrusting this analysis indicates that strain class is probably determined by a linear combination of convergence rate slab age and shallow slab dip interplate coupling controlled by convergence rate and slab age is an important control on strain regime and the primary control on earthquake magnitude arc parallel strike slip faulting is a common feature of convergent margins forming a forearc sliver between the strike slip fault and trench optimum conditions for the development of forearc slivers are oblique convergence a compressional environment and a continental overriding plate the primary factor controlling presence of strike slip faulting is coupling strongly oblique convergence is not required the rate of strike slip faulting is affected by both convergence obliquity and convergence rate maximum trench depth is a response to flexure of the underthrusting plate the amount of flexural deflection at the trench depends on the vertical component of slab pull force which is very sensitive to slab age and shallow slab dip shallow slab dip conforms to the cross sectional shape of the overriding plate which is controlled by width of the accretionary prism and duration of subduction deep slab dip is affected by the mantle trajectory established at shallow depth but may be modified by mantle flow much of the structural complexity of convergent margins is probably attributable to terrane juxtaposition associated with temporal changes in both forearc strike slip faulting and strain regime empirical equations relating subduction parameters can provide both a focus for future theoretical studies and a conceptual and kinematic link between plate tectonics and the geology of subduction zones

submillimeter scale topography of the lunar regolith we have applied computer stereophotogrammetry to apollo lunar surface closeup camera alscc pictures of the lunar surface to construct the first ever digital topographic relief maps of undisturbed lunar soil over spatial scales from 85 m to 8 5 cm using elevation histograms fractal analysis and hapke s photometric roughness model we show that apollo 14 fra mauro imbrium ejecta is rougher than average apollo 11 mare tranquilitatis and apollo 12 oceanus procellarum mare surfaces at submillimeter to decimeter size scales we confirm the early result of k lumme et al 1985 earth moon planets33 19 29 that the cumulative distribution of elevations for lunar soil is typically well described by gaussian statistics however cumulative distributions are insensitive to asymmetries in the shapes of elevation histograms of 11 discrete elevation histograms we measured about half exhibit significant deviations from gaussian behavior we also confirm lumme et al s finding that the roughnesses of all lunar surfaces increase with decreasing size scale we further show that the scale dependence of roughness is well represented by fractal statistics the rates of change of roughness with size scale represented by fractal dimension d are remarkably similar among terrians after correcting for the contribution of large scale roughness our average value of d 2 31 0 06 falls within the range 2 0 d 2 4 reported from lunar radar studies the amplitude of roughness which we characterize with the rms slope angle at 1 mm scale varies significantly among terrains for lunar mare the average rms slope angle is 16 4 3 and that for fra mauro regolith is 25 1 by comparison to radar data we suggest that the roughness of fra mauro imbrium ejecta regolith is similar to that of lunar highland terrains we find that the gaussian slope distribution assumed in b w hapke s model 1984 icarus59 41 59 adequately describes typical lunar regolith surfaces a revised form of hapke s equation that models realistic particle phase functions and the coherent backscatter opposition effect was fitted to disk resolved lunar photometric observations and yields estimates of 27 1 for highland and 24 1 for mare regolith these values of as well as the implied relative highland mare photometric roughness ratio are best matched in our elevation data by the cummulative contributions of surface topography covering all scales greater than 0 1 mm less than 5 of the photometrically detected roughness of lunar regolith is contributed by surface relief at scales larger than 8 cm this conclusion implies that values of derived from whole disk and disk resolved photometry respectively may be taken to represent the same physical quantity in addition particulate samples used in goniophotometric measurements should not be assumed to be photometrically smooth i e 0 as is often done in laboratory applications of hapke s photometric model the predicted photometric roughness at size scales of 0 1 mm and less significantly exceed photometric estimates and suggests that there exists a measurable size scale below which topographic relief either is not photometrically detectable or is not represented in the hapke model as macroscopic roughness

photometric anomalies of the lunar surface studied with smart 1 amie data we present new results from the mapping of lunar photometric function parameters using images acquired by the spacecraft smart 1 european space agency the source data for selected lunar areas imaged by the amie camera of smart 1 and the data processing are described we interpret the behavior of photometric function in terms of lunar regolith properties our study reveals photometric anomalies on both small sub kilometer and large tens of kilometers scales we found the regolith mesoscale roughness of lunar swirls to be similar in mare marginis mare ingenii and the surrounding terrains unique photometric properties related to peculiarities of the millimeter scale regolith structure for the reiner gamma swirl are confirmed we identified several impact craters of subkilometer sizes as the source of photometric anomalies created by an increase in mesoscale roughness within the proximal crater ejecta zones the extended ray systems reveal differences in the photometric properties between proximal and distant ejecta blankets basaltic lava flows within mare imbrium and oceanus procellarum indicate higher regolith porosity for the redder soils due to differences in the chemical composition of lavas

a very broad band inversion method for the recovery of earthquake source parameters abstract waveform studies of the earthquake source have traditionally been performed in narrow bands of the seismic spectrum waveform matching of p and sh waves emphasizes frequencies near and above the corner frequency normal mode and surface wave analyses on the other hand are performed on data which contain information only below the corner frequency a new method is presented which formally includes the result of a long period centroid moment tensor analysis in an inversion of broad band body wave phases a parametrized source model is used which allows for the recovery of a detailed source time function as well as the direction and magnitude of rupture propagation the technical details and the performance of the method are demonstrated in an analysis of the october 28 1983 borah peak idaho earthquake in particular it is shown how the combination of the long period and broad band data sets in the inversion improves the resolution of both the focal mechanism and the scalar moment the very broad band method is applied in an analysis of the september 19 1985 michoacan m w 8 0 earthquake two concentrations of moment release are identified in the source time function separated by 25 30 s in time the spatial distribution of moment is well explained both by a model of unilateral rupture towards the east with a propagation velocity of 2 4 km s 1 and by two point sources separated by 95 km it is shown that the p wave data are largely insensitive to the scalar moment and that source time functions obtained without consideration of the total moment release exaggerate the heterogeneity of slip on the fault plane source time functions which do contain the total moment show that a large fraction of the moment was released smoothly over the whole duration 80 s of the event the results suggest that the fault plane was characterized by two regions of high stress drop but that a large portion of slip occurred on surrounding weak portions of the plane

focal depth determination of central aleutian earthquakes focal depths of suboceanic subduction zone earthquakes best determined by the careful identification and analysis of teleseismic depth phases on short period vertical component seismograms arc crustal structure can cause water surface reflections pwp and swp and sediment basement reflections defined here as pp and sp with amplitudes comparable to those of water sediment reflections pp and sp however changes in source mechanism and local variations in arc structure make the observation of these short period depth phases highly unpredictable digital and analog vertical component seismograms were examined from nearly 400 teleseismically recorded central aleutian earthquakes that occurred during the period 1964 to 1984 a data set consisting of the travel times relative to p of short period depth phases was assembled for 54 shallow depth earthquakes and 33 earthquakes deeper than 50 km across the arc in addition long period waveforms for the larger events were examined magnitude mb 4 8 was approximately the lower limit for useful depth phase arrivals short period reflected phases from shallow depth earthquakes were analyzed by matching observed travel times relative to p to theoretical values computed for a two dimensional model of arc crustal structure depths resolved in this fashion provide a sharper depth profile of the shallow seismic zone in the central aleutians than previously available outer rise and trench earthquakes occur over a narrow range of subcrustal depths north of the trench the plate dips gently beneath the terrace and appears to descend gradually into the mantle the thickness of the interplate thrust earthquake zone is no more than 10 to 15 km earthquakes near the volcanic arc and above the plate interface occur at depths beneath the sediment basement interface estimation of the focal depths of earthquakes deeper than 50 km poses a special problem because an accurate specification of slab structure is needed to correct for path effects the phases pwp and swp are ordinarily only weakly recorded on long period vertical component seismograms however long period waves reflected from boundaries with sharp long period impedance contrasts such as the sea bottom and the sediment basement interface are strongly recorded moment tensor depths for shallow earthquakes based on the inversion of long period waveforms using a standard earth model once transformed into true depths within a model of arc crustal structure for the central aleutians agree with depths determined from short period reflected phases alone to within a few kilometers reported depth phases are routinely used for depth determination by the preliminary determination of epicenters pde and the international seismological centre isc services however the phases pp and sp are often obscured in the p coda and for suboceanic earthquakes e g pwp is misidentified and reported as pp this often results in the overestimation of the focal depths of routinely determined hypocenters reported by these services

local topographic effects on photometry and reflectance spectra of planetary surfaces an example based on lunar photometry the photometric properties of the average lunar surface are characterized using hapkes equations and whole disk observations ranging from 0 36 to 1 06 m synthetic spectra across a crater topographic profile arecreated using the modeling results the synthetic spectra are examined for spectral variations created by changes in lighting conditions induced by the topography changes above the modeling uncertainties are seen in both spectral slope and band depths though the most pronounced change is in band depth the data have insufficient spectral resolution to determine if there are any changes in band center due to photometric effects no additional absorption features are introduced by the photometry these results have serious implications on the interpretation of spectral observations in terms of abundance estimates and alteration processes as a function of location and association with geologic features

lunar photometric properties at wavelengths 0 5 1 6 μm acquired by selene spectral profiler and their dependency on local albedo and latitudinal zones abstract the lunar photometric function which describes the dependency of the observed radiance on the observation geometry is used for photometric correction of lunar visible near infrared data a precise photometric correction parameter set is crucial for many applications including mineral identification and reflectance map mosaics we present for the first time spectrally continuous photometric correction parameters for both sides of the moon for wavelengths in the range 0 5 1 6 m and solar phase angles between 5 and 85 derived from kaguya selene spectral profiler sp data since the measured radiance also depends on the surface albedo we developed a statistical method for selecting areas with relatively uniform albedos from a nearly 7000 orbit sp data set using the selected data set we obtained empirical photometric correction parameter sets for three albedo groups high medium and low we did this because the photometric function depends on the albedo especially at phase angles below about 20 for which the shadow hiding opposition effect is appreciable we determined the parameters in 160 bands and discovered a small variation in the opposition effect due to the albedo variation of mafic mineral absorption the consistency of the photometric correction was checked by comparing observations made at different times of the same area on the lunar surface variations in the spectra obtained were lower than 2 except for the large phase angle data in mare lastly we developed a correction method for low solar elevation data which is required for high latitude regions by investigating low solar elevation data we introduced an additional correction method we used the new photometric correction to generate a 1 mesh global lunar reflectance map cube in a wavelength range of 0 5 1 6 m surprisingly these maps reveal that high latitude 75 regions in both the north and south have much lower spectral continuum slopes color ratio r 1547 7nm r 752 8nm 1 8 than the low and medium latitude regions which implies lower degrees of space weathering

galileo observations of europa s opposition effect abstract during galileo s g7 orbit the solid state imaging ssi camera acquired pictures of the spacecraft shadow point on europa s surface as well as a comparison set of images showing the same geographic region at phase angle 5 coverage obtained at three spectral bandpasses vlt 0 41 m grn 0 56 m and 1mc 0 99 m at a spatial resolution of 404 m pixel shows a 162 220 km region of europa s surface located at 30 n 162 w we have used these images to measure the near opposition spectrophotometric behavior of four primary europan terrain materials ir bright icy material ir dark icy material dark lineament material and dark spot material the high spatial resolution of the g7 images reveal low albedo materials in dark spots that are among the darkest features 17 albedo at 0 56 m and 5 phase yet found on icy galilean satellites while material of comparable albedo is found on ganymede and callisto low albedo europan materials are much redder all europan surface materials exhibit an opposition effect however the strength of the effect as measured by the total increase in reflectance as phase angle decreases from 5 to 0 varies among terrains the opposition effects of ir bright icy and ir dark icy materials which dominate europa s surface are about 1 5 times larger than predicted from pre galileo studies low albedo materials in dark spots exhibit unusually intense opposition effects up to four times larger than bright icy europan terrains consistent with the presence of a strong shadow hiding opposition surge the strengths of the opposition surges among average europan terrains systematically vary with terrain albedo and can be explained in terms of the simultaneous contributions of shadow hiding and coherent backscatter to the total opposition effect coherent backscatter introduces a narrow angular contribution

application of a radiative transfer model to bright icy satellites a radiative transfer model derived largely from the work of b w hapke 1981 j geophys res 86 3039 3054 and j d goguen 1981 ph d thesis cornell university ithaca n y is fit to voyager imaging observations of europa mimas enceladus and rhea it is possible to place constraints on the single scattering albedo the porosity of the optically active upper regolith the single particle phase functions and in the cases of europa and mimas the mean slope angle of macroscopic surface features the texture of the surfaces of the saturnian satellites appears to be similar to the earth s moon however europa is found to have a distinctly more compact regolith and a more forward scattering single particle phase function

preliminary results on photometric properties of materials at the sagan memorial station mars reflectance measurements of selected rocks and soils over a wide range of illumination geometries obtained by the imager for mars pathfinder imp camera provide constraints on interpretations of the physical and mineralogical nature of geologic materials at the landing site the data sets consist of 1 three small photometric spot subframed scenes covering phase angles from 20 to 150 2 two image strips composed of three subframed images each located along the antisunrise and antisunset lines photometric equator covering phase angles from 0 to 155 and 3 full image scenes of the rock yogi covering phase angles from 48 to 100 phase functions extracted from calibrated data exhibit a dominantly backscattering photometric function consistent with the results from the viking lander cameras however forward scattering behavior does appear at phase angles 140 particularly for the darker gray rock surfaces preliminary efforts using a hapke scattering model are useful in comparing surface properties of different rock and soil types but are not well constrained possibly due to the incomplete phase angle availability uncertainties related to the photometric function of the calibration targets and or the competing effects of diffuse and direct lighting preliminary interpretations of the derived hapke parameters suggest that 1 red rocks can be modeled as a mixture of gray rocks with a coating of bright and dark soil or dust and 2 gray rocks have macroscopically smoother surfaces composed of microscopically homogeneous clear materials with little internal scattering which may imply a glass like or varnished surface

properties of the hermean regolith iv photometric parameters of mercury and the moon contrasted with hapke modelling a comparison of the photometric properties of mercury and the moon is performed based on their integral phase curves and disk resolved image data of mercury obtained with the swedish vacuum solar telescope proper absolute calibration of integral v band

photometric anomalies of the lunar surface results from clementine data 1 we mapped the photometric characteristics of the lunar surface for several small areas using clementine uvvis camera images the maps of the phase function steepness showed several anomalous sites several small fresh impact craters have anomalous halos in these maps the phase function within the halos is less steep than for the surrounding mare surface we interpret these halos to be due to geologically recent impact caused alteration of the equilibrium millimeter scale regolith structure this equilibrium structure is established through micrometeoritic bombardment at a geologically short timescale an anomaly of the same signature was found at the apollo 15 landing site we interpret it as being a result of the regolith structure alteration with the lander jets a unique photometric anomaly not correlated with albedo was found within the reiner gamma formation we suggest that this anomaly is genetically related to the formation which indicates its young age this favors the impact hypothesis for the nature of the reiner gamma formation our study showed that mapping of photometric characteristics is a new powerful tool in studies of the surfaces of atmosphereless bodies future photometric studies of the moon with existing and new data sets are promising for a search for traces of recent seismic events studies of the recent population of meteoroids in the inner solar system an advance in the understanding of swirls etc

of the may 7 1986 andreanof islands earthquake source parameters source characteristics of the may 7 1986 andreanof islands earthquake 51 412 n 174 830 w neic are investigated from wwssn gdsn and ida records first motions from over 60 stations determine one steeply dipping nodal plane we constrained this nodal plane and inverted long period surface waves at a period of t 256 sec and determined the second nodal plane to be dip 18 rake 116 and strike 257 this shallowly dipping thrust mechanism is consistent with plate motions in this region seismic moment from surface wave inversion is 1 3 1028 dyne cm corresponding to mw 8 0 amplitudes of body and surface waves from short period instruments yield magnitudes of and ms 7 7 the teleseismic average p wave moment rate spectrum from 17 short and intermediate period instruments is slightly lower than that of an average mw 8 0 subduction zone event we constrained the fault plane as determined above to deconvolve the first 90 secs of the long period body wave at 11 teleseismic stations to determine the source time function and the spatial distribution of moment release the source time function consists of 4 moment releasing episodes which have a total moment release of 9 4 1027 dyne cm the fault ruptured bilaterally with the largest moment releasing subevent occurring between 30 45 sec this subevent nucleates approximately 75 90 km west of the determined epicenter this region corresponds to the epicentral area of the 1957 great aleutian earthquake which is one of the largest earthquakes in recorded history

a comparison of the spatio temporal distribution of moment release for the 1986 andreanof islands earthquake with relocated seismicity we compare relocated teleseismically recorded seismicity before and after the may 7 1986 andreanof islands earthquake mw 8 to the spatial and temporal distribution of seismic moment release during the mainshock relocated seismicity from 1964 through april 1987 clusters strongly along the main thrust zone in similar locations for the pre and post mainshock periods we performed simultaneous iterative inversions of broadband teleseismic gdsn and nars p waveforms using the method of kikuchi and fukao 1987 fault plane parameters e g strike dip depth and extent of fault plane consistent with regional tectonics and aftershock locations were specified the results of the inversions are spatial and temporal maps of moment release on the fault plane most of the moment found by the inversion is localized in several regions of the fault plane resolution of the location and timing of the major subevents is good the rupture was bilateral with a highly variable rupture velocity a shallow updip region of the fault plane ruptured toward the end of the mainshock process the mainshock moment release tended to occur in regions of the fault plane in which no or few aftershocks or preshocks are located this tendency suggests that regions of high moment release in the 1986 andreanof islands earthquake resulted from rupture of mechanically strong regions i e asperities on the fault plane which exhibited little seismicity before or after the mainshock that ruptured them we infer that the asperity regions were locked and quiescent before the mainshock while surrounding seismically active areas did not store as much strain and slipped mostly aseismically

simulation of multiangular radar echoes for speed measurement during ce 3 landing on the lunar sinus iridum surface the main objective of the chinese chang e 3 ce 3 lunar satellite is to achieve soft landing and roving exploration on the lunar surface a multibeam radar in the lunar lander is implemented to measure the echoes from the lunar rough surface during its descending and to derive the speed of the lander in this paper numerical simulation of multiangular radar echoes and speed inversions from doppler frequency are presented an area of the lunar sinus iridum bay as landing site is specifically selected the rough surface described with the real dtm data is first divided into triangular patches for numerical kirchhoff approximation calculation the radar echoes of multiangular radar beams of ce 3 during the landing are numerically simulated the echo phase and the doppler frequency are then derived to obtain the vertical speed

calibration against the moon i a disk resolved lunar model for absolute reflectance calibration abstract we present a model of the absolute radiance of the disk resolved moon at visible to near infrared wavelengths it has been developed in order to use the moon as a calibration reference particularly by space based sensors observing the earth we begin with the development of hillier et al hillier j buratti b hill k 1999 icarus 141 205 225 for the reflectance as a function of phase angle and base the lunar reflectance on the clementine 0 750 m basemap we adopt hapke s hapke b 2002 icarus 157 523 534 expression for the multiple scattering term including the more accurate approximation to the chandrasekhar h function the geometry is based on the jet propulsion laboratory lunar ephemeris de 421 and the topographic slope is from the kaguya lalt laser altimetry araki h and 10 colleagues 2009 science 323 897 900 we define three types of terrain by combining the reflectance from the clementine basemap and the topographic model to specify maria highlands and crater regions and allow mixed types between each class parameters of the model are solved for as a function of surface type and wavelength by comparison against data chips from the robotic lunar observatory rolo kieffer h h stone t c 2005 astron j 129 2887 2901 the reflectance in any waveband may be computed by spectral interpolation of the model predictions relative to the scaled apollo 16 soil spectrum the accuracy of the model evaluated against rolo imagery was found to be 2 4

iterative deconvolution of complex body waves from great earthquakes the tokachi oki earthquake of 1968 abstract a method of body wave inversion is developed in an attempt to extract the information about asperities or barriers in a fault zone a sequence of point sources each being characterized with the seismic moment the onset time and the location are iteratively derived from observed records at multi stations where the two dimensional extent of the source location is taken into account a modification is made of the iterative method of kikuchi and kanamori on the formulation of inversion procedure to facilitate the computation using this method we analyse long period p waves of the tokachi oki earthquake of 1968 mw 8 2 and obtain several significant subevents with time durations of 10 s their spatio temporal distribution shows that the rupture process consists of three characteristic stages a a stage of introductory rupture b a stage of main rupture and c a stage of aftershocks the main rupture takes place in the form of clustering around a few sites of the fault plane the largest subevent occurs in the northwestern corner the stress drop associated with this event is estimated to be 200 bars one order of magnitude higher than the stress drop averaged over the entire fault plane the sum of the seismic moments of the individual subevents amounts to 2 3 1028 dyn cm which approximately coincides with the one estimated from the analysis of long period surface waves this implies that the source of the tokachi oki earthquake consists of several major subevents with time durations of 10 s in addition to other minor subevents

in situ optical measurements of chang e 3 landing site in mare imbrium 2 photometric properties of the regolith the panorama cameras onboard the yutu rover of the chang e 3 lunar mission acquired hundreds of high resolution color images of the lunar surface and captured the first in situ lunar opposition effect oe since the apollo era we extracted the phase curve and the color ratio in three bands with the phase angle range from 2 degrees to 141 degrees photometric inversions using the hapke model reveal that submicroscopic dusts are present in the landing area and both the coherent backscattering and the shadow hiding are responsible for the strong oe compared with spaceborne measurements the grains in the landing site are brighter more transparent and appear to be better crystallized than the average maria basaltic grains the results show that the phase reddening effect appears to be present in the in situ phase curves the current phase curve can be used as the ground truth validations of any future spaceborne phase curve measurement over the landing site region

photometry of triton 1992 2004 surface volatile transport and discovery of a remarkable opposition surge abstract triton the large satellite of neptune was imaged by the voyager 2 spacecraft in 1989 with dark plumes originating in its volatile rich south polar region southern summer solstice a time when seasonal volatile transport should be at a maximum occurred in 2001 ground based observations of triton s rotational light curve obtained from table mountain observatory in 2000 2004 reveal volatile transport on its surface when compared with a static frost model constructed from voyager images the light curve shows an increase in total amplitude an earlier light curve obtained in 1992 from mauna kea observatory is consistent with the static frost model this movement of volatiles on the surface agrees with recent imaging results from the hubble space telescope bauer j m buratti b j li j y mosher j a hicks m d schmidt b e goguen j d 2010 astrophys j 723 l49 l52 the changes in the light curve can be explained by the transport of nitrogen frost on the surface or by the uncovering of bedrock of less volatile methane we also find that triton exhibits a large opposition surge at solar phase angles less than 0 1 this surge cannot be entirely explained by the effects of coherent backscatter

subduction of aseismic ridges beneath the caribbean plate implications for the tectonics and seismic potential of the northeastern caribbean normal seafloor entering the puerto rico and northern lesser antillean trenches in the northeastern caribbean is interrupted by a series of aseismic ridges on the north and south american plates these topographic features lie close to the expected trend of fracture zones created about 80 110 m y ago when this seafloor was formed at the mid atlantic ridge the northernmost of the ridges that interact with the lesser antillean subduction zone the barracuda ridge intersects the arc in a region of high seismic activity some of this seismicity including a large shock in 1974 occurs within the overthrust plate and may be related to the deformation of the caribbean plate as it overrides the ridge a large bathymetric high the main ridge is oriented obliquely to the puerto rico trench and intersects the subduction zone north of the virgin islands in another cluster of seismic activity along the inner wall of the trench data from a seismic network in the northeastern caribbean indicate that this intersection is also characterized by both interpolate and intraplate seismic activity magnetic anomalies bathymetric trends and the pattern of deformed sediments on the inner wall of the trench strongly suggest that the main and barracuda ridges are parts of a formerly continuous aseismic ridge a segment of which has recently been overridden by the caribbean plate reconstruction of mid miocene to recent plate motions also suggest that at least two aseismic ridges and possibly fragments of the bahama platform have interacted with the subduction zone in the northeastern caribbean the introduction of these narrow segments of anomalous seafloor into the subduction zone has segmented the arc into elements about 200 km long these ridges may act as tectonic barriers or asperities during the rupture processes involved in large earthquakes they also leave a geologic imprint on segments of the arc with which they have interacted a 50 km landward jump of the locus of island arc volcanism occurred in late miocene time along the northern half of the lesser antilles we postulate that the subduction of a segment of seafloor of anomolously thick crust being more buoyant than adjacent seafloor resulted in a marked shoaling in the dip of the descending slab and therefore a shift of the locus of volcanism in the region near western puerto rico and eastern hispanolia plio pleistocene interaction with a similar feature in this case a part of the bahama platform about 3 4 m y ago led to a jump in the locus of subduction as evidenced by a gap in the downgoing seismic zone that segment of the bahama platform interferred with the subduction process and was subsequently sutured onto the caribbean plate when the boundary jumped about 60 km to the northeast the maximum size of historic shallow earthquakes along the lesser antillean arc varies from about 7 0 7 5 in the center of the arc where the dip of the shallow part of the plate boundary is steep to 8 0 8 5 along the northern part of the arc where the dip is shallow the interaction of anomalous seafloor as along the northern lesser antilles can lead to the development of a wider than normal zone of interplate contact and hence to earthquakes that are larger than those associated with more typical seafloor entering subduction zones major seismic gaps and regions of high seismic potential currently exist along the northern lesser antilles and to the north of puerto rico both gaps are bounded by anomalous features on the downgoing plate the intersection of these features with the plate boundary created large asperities that may be good places to search for precursors to future large earthquakes a great shock in 1787 may have ruptured an existing seismic gap north of puerto rico between 65 and 67 w thus that gap can be expected to eventually rupture again in a great shock and not to accommodate plate motion by totally aseismic processes

earthshine and the earth s albedo 1 earthshine observations and measurements of the lunar phase function for accurate measurements of the earth s bond albedo 1 we have been making sustained observations of the earthshine from big bear solar observatory in california since late 1998 we also have intermittent observations from 1994 1995 we have reinvigorated and modernized a nearly forgotten way of measuring the earth s albedo and hence its energy balance previously studied by a danjon and his followers for about 25 years early in the last century using their observations of the earthshine from france this is the first in a series of papers covering observations and simulations of the earth s reflectance from photometric and spectral observations of the moon here we develop a modern method of measuring instantaneously the large scale reflectance of the earth from california we see the moon reflecting sunlight from the third of the earth to the west of us in our evening before midnight which is during the moon s rising phase and from the third of the earth to our east in our morning after midnight which is during the moon s declining phase we have precisely measured the scattering from the moon as a function of lunar phase which enables us to measure in a typical night s observations the earth s reflectance to an accuracy of 2 0 equivalent to measuring the earth s emission temperature to 0 8 k we have also identified the lunar phase function as the major source of discrepancy between danjon s estimates of the albedo and more recent measurements the albedo is due to the interplay of cloud cover and different landscapes

multispectral photometry of the moon and absolute calibration of the clementine uv vis camera abstract we present a multispectral photometric study of the moon between solar phase angles of 0 and 85 using clementine images obtained between 0 4 and 1 0 m we produce a comprehensive study of the lunar surface containing the following results 1 empirical photometric functions for the spectral range and viewing and illumination geometries mentioned 2 photometric modeling that derives the physical properties of the upper regolith and includes a detailed study of the causes for the lunar opposition surge 3 an absolute calibration of the clementine uv vis camera the calibration procedure given on the clementine calibration web site produces reflectances relative to a halon standard and further appear significantly higher than those seen in groundbased observations by comparing clementine observations with prior groundbased observations of 15 sites on the moon we have determined a good absolute calibration of the clementine uv vis camera a correction factor of 0 532 has been determined to convert the web site www planetary brown edu clementine calibration html reflectances to absolute values from the calibrated data we calculate empirical phase functions useful for performing photometric corrections to observations of the moon between solar phase angles of 0 and 85 and in the spectral range 0 4 to 1 0 m finally the calibrated data is used to fit a version of hapke s photometric model modified to incorporate a new formulation developed in this paper of the lunar opposition surge which includes coherent backscatter recent studies of the lunar opposition effect have yielded contradictory results as to the mechanism responsible shadow hiding coherent backscatter or both we find that most of the surge can be explained by shadow hiding with a halfwidth of 8 however for the brightest regions the highlands at 0 75 1 0 m a small additional narrow component halfwidth of

the lunar opposition surge observations by clementine abstract the clementine mission to the moon in 1994 provided the first multispectral observations of the lunar opposition surge below a few degrees the brightness of the moon increases more than 40 between solar phase angles of 4 and 0 the opposition effect exhibits a small wavelength dependence the surge is 3 4 larger at 0 41 m than at 1 00 m this result suggests that the principal cause of the lunar opposition surge is shadow hiding while coherent backscatter if present makes only a minor contribution the amplitude of the effect depends significantly on terrain the surge is about 10 greater in the lunar highlands this difference is attributed to textural variations between the two terrains the clementine measurements provide a new basis for deriving spectral geometric albedos phase integrals and bond albedos a value of 0 11 0 01 was found for the lunar bolometric bond albedo this value is at the low end of the historical published values but not as low as the recent result of 0 080 0 002

opposition effect of the moon from lroc wac data abstract lroc wac images acquired in 5 bands of the visible spectral range were used to study the opposition effect for two mare and two highland regions near the lunar equator opposition phase curves were extracted from the images containing the opposition by separating the phase curve effect from the albedo pattern by comparing wac images at different phase angles from 0 to 30 akimov s photometric function and the nasa digital terrain model gld100 were used in the processing it was found that phase curve slopes at small phase angles directly correlate with albedo while at larger phase angles they are anti correlated we suggest a parameter to characterize the coherent backscattering component of the lunar opposition surge which is defined as the maximum phase angle for which the opposition surge slope increases with growing albedo the width of the coherent backscattering opposition effect varies from approximately 1 2 for highlands in red light to 3 9 for maria in blue light the parameter depends on albedo which is in agreement with the coherent backscattering theory the maximum amplitude of the coherent opposition effect is estimated to be near 8 maps of albedo and phase curve slope at phase angles larger than those at which the coherent backscattering occurs were built for the areas under study absolute calibration of wac images was compared with earth based observations the wac determined albedo is very close to the mean lunar albedo calculated using available earth based observations

an experiment in systematic study of global seismicity centroid moment tensor solutions for 201 moderate and large earthquakes of 1981 data from the global digital seismograph network were used to obtain centroid moment tensor solutions using the method of dziewonski et al 1981 results were obtained for 201 earthquakes ranging in seismic moment from 7 1023 to 3 1027 dyne cm the wide dynamic range of the sro asro stations allows us to investigate using the same algorithm series of events among which the smallest and the largest may differ in moment by a factor as large as 1000 among the events studied is a particularly interesting series in january 1981 off the island of honshu the main shock was preceded by three foreshocks and followed by four aftershocks all falling within the range of our analysis there is an indication that the source mechanism changes with the size of the event statistical analysis of the results for all earthquakes reveals that the half duration of shallow and intermediate events is approximated by 1 6 10 8 m01 3 the shifts in origin time for deep focus earthquakes are indicative of the general complexity of these events which depends only weakly on the seismic moment the extreme departures from a double couple mechanism seem to depend both on the moment and on the focal depth while for shallow earthquakes these departures decrease from a maximum at about 1025 dyne cm with increasing moment the reverse appears to be true with respect to deep focus earthquakes shallow earthquakes north of new guinea and along the solomon islands show systematic and substantial departures from the double couple mechanism

spectrogoniometry and modeling of martian and lunar analog samples and apollo soils abstract we present new visible near infrared multispectral reflectance measurements of seven lunar soil simulants two apollo soils and eight martian analog samples as functions of illumination and emission angles using the bloomsburg university goniometer by modeling these data with hapke theory we provide constraints on photometric parameters single scattering albedo phase function parameters macroscopic roughness and opposition effect parameters to provide additional ground truth photometric properties to assist analyses of spacecraft data a wide range of modeled photometric properties were variably related to albedo color grain size and surface texture finer grained samples here have high single scattering albedo values compared to their coarser grained counterparts as well as lower macroscopic roughness values the mars analog samples and apollo soils exhibit slightly lower opposition effect width parameter values than the lunar analogs whereas the opposition effect magnitude is not well constrained by the models the mars analog soils are typically relatively backscattering and consistent with fairly rough particles with a moderate density of internal scatterers similar to the in situ observations of some soils by the mars exploration rover mer spirit some lunar analog soil models result in moderately forward scattering behaviors as do the two apollo soils other fine grained and or glass rich lunar analog samples populate a narrowly forward scattering regime similar to model results from observations of some rover tracks observed by the mer opportunity rover and some dust poor gray rocks by the spirit rover an experiment to mimic the spherule rich soils observed by opportunity demonstrated a large decrease in single scattering albedo compared to spherule free soil surfaces as well as increased surface roughness narrow opposition effects and a significant increase in backscattering similar to some of the opportunity soils phase reddening effects are documented in many soils as an increase in near infrared visible ratios with phase angle some samples exhibit falloffs in these ratio phase curves at phase angles beyond 50 80 that are likely related to an increased importance of surface scattering at high phase angles none of the lunar analog soils perfectly match the modeled photometric parameters of the two apollo soils the phase reddening nature of the mare soil included an upturn in ratio values at phase angles

compositional analyses of small lunar pyroclastic deposits using clementine multispectral data clementine ultraviolet visible uvvis data are used to examine the compositions of 18 pyroclastic deposits 15 small three large at 13 sites on the moon compositional variations among pyroclastic deposits largely result from differing amounts of new basaltic or juvenile material and reworked local material entrained in their ejecta upon eruption characterization of pyroclastic deposit compositions allows us to understand the mechanisms of lunar explosive volcanism evidence for compositional differences between small pyroclastic deposits at a single site is observed at atlas crater at all sites compositional variation among the small pyroclastic deposits is consistent with earlier classification based on earth based spectra three compositional groups can be observed and the trend of increasing mafic absorption band strength from group 1 to group 2 to group 3 is noted as redefined here group 1 deposits include those of alphonsus west alphonsus southeast alphonsus northeast 2 atlas south cruger franklin grimaldi lavoisier oppenheimer orientale and riccioli group 1 deposits resemble lunar highlands with weak mafic bands and relatively high uv vis ratios group 2 deposits include those of alphonsus northeast 1 atlas north eastern frigoris east and west and aristarchus plateau group 2 deposits are similar to mature lunar maria with moderate mafic band depths and intermediate uv vis ratios the single group 3 deposit j herschel has a relatively strong mafic band and a low uv vis ratio and olivine is a likely juvenile component two of the deposits in these groups orientale and aristarchus are large pyroclastic deposits the third large pyroclastic deposit apollo 17 taurus littrow has a very weak mafic band and a high uv vis ratio and it does not belong to any of the compositional groups for small pyroclastic deposits the observed compositional variations indicate that highland and mare materials are also present in many large and small pyroclastic deposits and they suggest that volcanic glasses or spheres may not be dominant juvenile components in all large pyroclastic deposits

inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 imperial valley california earthquake a least squares point by point inversion of strong ground motion and teleseismic body waves is used to infer the fault rupture history of the 1979 imperial valley california earthquake the imperial fault is represented by a plane embedded in a half space where the elastic properties vary with depth the inversion yields both the spatial and temporal variations in dislocation on the fault plane for both right lateral strike slip and normal dip slip components of motion inversions are run for different fault dips and for both constant and variable rupture velocity models effects of different data sets are also investigated inversions are compared which use the strong ground motions alone the teleseismic body waves alone and simultaneously the strong ground motion and teleseismic records the inversions are stabilized by adding both smoothing and positivity constraints the moment is estimated to be 5 0 10 25 dyne cm and the fault dip 90 5 dislocation in the hypocentral region south of the united states mexican border is relatively small and almost dies out near the border dislocation then increases sharply north of the border to a maximum of about 2 m under interstate 8 dipslip motion is minor compared to strike slip motion and is concentrated in the sediments the best fitting constant rupture velocity is 80 per cent of the local shear wave velocity however there is a suggestion that the rupture front accelerated from the hypocenter northward the 1979 imperial valley earthquake can be characterized as a magnitude 5 earthquake at the hypocenter which then grew into or triggered a magnitude 6 earthquake north of the border

arctic abyssal t phases coupling seismic energy to the ocean sound channel via under ice scattering earthquakes along the mid arctic ridge radiate earthborne compressional and shear waves that couple into the arctic acoustic channel and propagate as t phases the t phase energy is transmitted above the epicenter through the seafloor at near vertical angles scattering from the ice surface couples some of this energy into waterborne angles at 5 hz the coupled energy is about 40 db down from the incident levels and at 15 hz it is about 30 db down scattering accounts for the characteristic spectral shape of the abyssal t phase that is more energetic at 15 hz than 5 hz several t phase arrivals were recorded on hydrophones during the fram ii experiment from the measured acoustic levels a transmission loss prediction between source and receiver and the scattering conversion losses the microearthquake acoustic source level in the water column is estimated to be about 250 db re 1 pa hz at 5 hz and 235 db re 1 pa hz at 15 hz these levels lead to a crustal attenuation estimate of 0 52 db km at 5 hz that is consistent with fram ii refraction measurements work supported by onr

a photometric function for analysis of lunar images in the visual and infrared based on moon mineralogy mapper observations 1 changes in observed photometric intensity on a planetary surface are caused by variations in local viewing geometry defined by the radiance incidence emission and solar phase angle coupled with a wavelength dependent surface phase function f which is specific for a given terrain in this paper we provide preliminary empirical models based on data acquired inflight which enable the correction of moon mineralogy mapper m3 spectral images to a standard geometry with the effects of viewing geometry removed over the solar phase angle range for which the m3 data were acquired our models are accurate to a few percent particularly where thermal emission is not significant our models are expected to improve as additional refinements to the calibrations occur including improvements to the flatfield calibration improved scattered and stray light corrections improved thermal model corrections and the computation of more accurate local incident and emission angles based on surface topography