earthquakes in northern europe in 1375 1989 abstract an updated version of the catalogue of earthquakes in northern europe is presented it comprises events inside a region window of about 55 80 n and 10 w 45 e covering a 615 year period from 1375 to 1989 the data have been compiled using all the available historical publications catalogues studies and reports of the region and for events from 1984 to 1989 a regional seismic parameter database maintained by the institute of seismology of the university of helsinki the number of events exceeds 5200 of which more than 40 have been registered since 1980 the huge increase of event reports is the result of the installation of new high frequency networks for microearthquake studies and the upgrade of the seismic instrumentation because of the different degree of accuracy and homogeneity of the parameter data the events were divided into historical 1375 1964 and instrumental 1965 1989 datasets the source parameters are mainly macroseismic for historical events and obtained by iterative location procedure for instrumental data by assuming internal homogeneity between the different regional magnitude scales we estimated the catalogue to be complete for events with magnitude 4 5 since the 1880 s magnitude 4 0 4 4 since the 1940 s and magnitude 3 5 3 9 since the 1970 s although the distribution of seismicity exhibits similar patterns in both datasets the clustering of epicenters and offshore seismicity is more distinct in the instrumental period the occurrence of the greatest events can be seen more clearly in the historical data the earthquake epicenters are concentrated in the geologically younger tectonic provinces in the western part of the region and follow with some exceptions the tectonic fracture and fault zones in the fennoscandian area 80 of the earthquakes occurred in the upper 20 km of the earth s crust the deepest epicenters are in the southwestern corner of the region where the crust is thinnest

source parameters of the 2014 mw 6 1 south napa earthquake estimated from the sentinel 1a cosmo skymed and gps data abstract using the combination of two insar and one gps data sets we present the detailed source model of the 2014 mw 6 1 south napa earthquake the biggest tremor to hit the san francisco bay area since the 1989 mw 6 9 loma prieta earthquake the insar data are from the sentinel 1a s1a and cosmo skymed cs satellites and gps data are provided by nevada geodetic laboratory we firstly obtain the complete coseismic deformation fields of this event and estimate the insar data errors then using the s1a data to construct the fault geometry one main and two short parallel sub faults which haven t been identified by field investigation as expected the geometry is in good agreement with the aftershock distribution by inverting the insar and gps data we derive a three segment slip and rake models our model indicates that this event was a right lateral strike slip earthquake with a slight reverse component in the west napa fault as we estimated the fault is 30 km long and more than 80 of the seismic moment was released at the center of the fault segment where the slip reached its maximum up to 1 m we also find that our geodetic moment magnitude is 2 07 1018 nm corresponding to mw 6 18 larger than that of usgs mw 6 0 and gcmt mw 6 1 this difference may partly be explained by our insar data including about one week s postseismic deformation and aftershocks the results also demonstrate high snr and great ability of the newly launched sentinel 1a in earthquake study furthermore this study suggests that this earthquake has potential to trigger nearby faults especially the green valley fault where the coulomb stress was imparted by the 2014 south napa earthquake

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

real time reliable magnitudes for large earthquakes from 1 hz gps precise point positioning the 2011 tohoku oki japan earthquake 1 the early warning issued after the onset of the mw9 0 tohoku oki earthquake significantly underestimated its magnitude saturating 120 seconds after the earthquake began at mw8 1 here we investigate whether real time deformation data from japan s dense network of continuously recording global positioning system gps stations could have been used to provide a more reliable rapid estimate of the earthquake s magnitude and ultimately a more robust tsunami forecast we use precise point positioning in real time mode with broadcast clock and orbital corrections to give station positions every 1 s we then carry out a simple static inversion on a subset of stations to determine the portion of the fault that slipped and the earthquake magnitude unlike most previous methods our method produces estimates of seismic moment before the earthquake rupture has completed we find that the deformation data allow a robust magnitude estimate just 100 s after the earthquake onset we also investigated the density of stations required for a robust moment magnitude estimate fewer than 1 station every 100 km are needed we recommend that gps data be incorporated into earthquake early warning systems for regions at threat from large magnitude earthquakes and tsunamis

reverse water level change during interference slug tests in fractured rock 1 reverse water level responses in monitoring wells are widely known during pumping tests where they are recognized as the noordbergum or rhade effects and a similar response was observed in many of the 100 interference slug tests conducted at a well field near clemson south carolina the reverse water level effect is characterized by a drop in pressure head by 1 cm to several centimeters and it occurs in the first 10 100 s of the test the reverse response is followed by a rise and fall of pressure head that is typical of slug in tests the reverse water level response is highly repeatable and it increases when the pressure used to create the slug test is increased a conceptual model recognizes that opening displacement of the fracture wall can cause a pressure drop even when the pressure increases in the wellbore the conceptual model is supported by a closed form analytical solution and a numerical model that couple fluid pressure and deformation in a fracture characteristics of the reverse water level response are sensitive to properties of the fracture system and enveloping formation parameter estimation methods can be used to invert theoretical analyses and use the reverse response to improve the characterization of fractured rock aquifers

analysis of the reliability and resolution of the earthquake source history inferred from waveforms taking the chi chi earthquake as an example summary in the inversion of observed waveforms to obtain the earthquake source faulting process some uncertain factors may influence the reliability of the results several numerical tests have been analysed in this paper in order to understand the effect of some of these uncertain parameters such as the number and width of multiple time windows that define the source time function the assumed strike and dip of the fault the velocity structure and noise also the influence of the sampling rate the time window of the data and the distribution of observational stations is studied our research indicates the near source waveform data can adequately recover the source rupture process of the shallow part of the fault however they poorly constrain the slip distribution on the deep part of the fault using near source and teleseismic waveform data jointly can provide a more complete view of the rupture process of the whole fault the result using near fault data is very sensitive to the assumed strike and dip parameters of the fault model a 2 deviation of the presumed strike and a 5 deviation of the presumed dip from that of the true fault will lead to a distorted inversion result the influence of the uncertainty of the seismic velocity structure for the chi chi earthquake might be ignored if we can take the difference between ma et al s model and wu et al s model as the measure of the media uncertainty

sedimentary anisotropy diverges from flute trends in south east finnish lapland abstract subglacial flutes are parallel to ice flow lineations indicative of glacial streamlining yet their depositional erosional origin or sedimentary anisotropy is not fully understood the flutes aligned nw se with a flow direction to the se are superimposed on westerly oriented drumlins in kuusamo south eastern finnish lapland 65 45 n and 29 40 e and reflect ice stream flow pattern towards the younger dryas end moraines ydems in russian karelia we investigated bedform morphology flutes drumlins and crescentic troughs as well as sedimentary anisotropy of flute ridges and troughs using digital elevation models dems airborne radiometric ar data and measurements of azimuthal electrical conductivity a the dem ar revealed elongation ratios l w from 2 1 to 25 1 yet the highest ratios reached l w 48 1 flutes in the study area fan towards the east and south east whereas the drumlins on which they are superimposed show ice flow from the west 280 the a anisotropy of the flute ridges and troughs indicates sedimentation from 340 to 350 diagonal with respect to both drumlins and flutes we found erosional crescentic troughs with down flow rims indicative of both phases but failed to find evidence for subglacial meltwater boulder lags or ice flow erosional bedrock bump sticky spots we contend that the studied flutes are erosional and date to the ydem phase yet the origin of the precursory sediments may date to early weichselian

storage change in a flat lying fracture during well tests 1 the volume of water released from storage per unit head drop per volume of an rev is a basic quantity in groundwater hydrology but the details of the process of storage change in the vicinity of a well are commonly overlooked we characterize storage change in a flat lying fracture or thin sedimentary bed through the apparent hydraulic compliance cf the change in aperture of the fracture or thickness of the layer per unit change in pressure the results of theoretical analyses and field measurements show that cf increases with time near the well during pumping but it drops suddenly and may become negative at the beginning of recovery during a well test profiles of cfincrease with radial distance from a well but they are marked by a sharp increase and a sharp decrease at the edge of the region affected by the wellbore pressure transient the conventional view in groundwater hydrology is that storage change at a point is proportional to the local change in pressure which requires that the hydraulic compliance is uniform and constant it appears that this conventional view is a simplification of a process that varies in both space and time and can even take on negative values this simplification may be a source of uncertainty when interpreting well tests and extensometer records or predicting long term well performance

source rupture process of the 2004 chuetsu mid niigata prefecture japan earthquake inferred from waveform inversion with dense strong motion data abstract the kinematic source rupture process of the 2004 chuetsu mid niigata prefecture japan earthquake is estimated from strong motion data by the linear waveform inversion method in order to develop appropriate green s functions one dimensional velocity structure models for each station are constructed by modeling the aftershock waveforms the estimated top of the bedrock is deeper at the western side of the fault and relatively shallow at the eastern side this tendency coincides with other investigations of seismic tomography and microtremor array observations the obtained source model shows large slips in the vicinity of the hypocenter the reverse slipping rupture originated from the deeper part of the fault and propagated toward the up dip and southwest directions the near surface slip is small two tests are demonstrated to check the stability of the obtained source model the first test examines the effects of the number of available stations on the solution and the second test examines how the difference in the target waveform type affects the solution the number of stations affects the variation of slip amount and more than 12 stations appear to be sufficient to obtain a stable solution in this case the difference in the target wave type in the data set does not significantly affect the solution if the number of stations is sufficient and the green s functions are well calibrated the model obtained using calibrated velocity structure models shows clear image of high slip area compared to the model obtained using a single velocity structure model

ice shaped ring forms in western canada their airphoto expressions and manifold polygenetic origins abstract a variety of ice shaped ring forms and patterns in western canada are strikingly expressed in black and white aerial photographs the most common forms are round and oval mounds and plateaus with rim ridges around summit craters it is speculated that small clusters and large fields of them originated from dead ice supraglacial and subglacial wasting processes and often from a combination of both where shallow glacial lake waters were present other ice shaped ring features and patterns illustrated in this paper result from former and present permafrost and periglacial activity groundwater discharge and winter ice mounding and expansion that transfer fine sediment from circular orifices to their margins slush formation that creates fractal like patterns on thin ice floating on shallow snow covered lakes and wind driven icebergs and lake ice that produce circular scours on the beds of glacial lakes portions of contact airphotos have been included to show better examples of ring forms and patterns in western canada speculations on their manifold polygenetic origins are presented

objective landslide detection and surface morphology mapping using high resolution airborne laser altimetry a map of extant slope failures is the most basic element of any landslide assessment without an accurate inventory of slope instability it is not possible to analyze the controls on the spatial and temporal patterns of mass movement or the environmental human or geomorphic consequences of slides landslide inventory maps are tedious to compile difficult to make in vegetated terrain using conventional techniques and tend to be subjective in addition most landslide inventories simply outline landslide boundaries and do not offer information about landslide mechanics as manifested by internal deformation features in an alternative approach we constructed accurate high resolution dems from airborne laser altimetry lidar data to characterize a large landslide complex and surrounding terrain near christchurch new zealand one dimensional circular 2 d and spherical 3 d statistics are used to map the local topographic roughness in the dems over a spatial scale of 1 5 to 10 m the bedrock landslide is rougher than adjacent unfailed terrain and any of the statistics can be employed to automatically detect and map the overall slide complex furthermore statistics that include a measure of the local variability of aspect successfully delineate four kinematic units within the gently sloping lower half of the slide features with a minimum size of surface folds that have a wavelength of about 11 to 12 m and amplitude of about 1 m are readily mapped two adjacent earthflows within the landslide complex are distinguished by a contrast in median roughness and texture and continuity of roughness elements the less active of the earthflows has a surface morphology that presumably has been smoothed by surface processes the laplacian operator also accurately maps the kinematic units and the folds and longitudinal levees within and at the margins of the units finally two dimensional power spectra analyses are used to quantify how roughness varies with length scale these results indicate that no dominant length scale of roughness exists for smooth unfailed terrain in contrast zones with different styles of landslide deformation exhibit distinctive spectral peaks that correspond to the scale of deformation features such as the compression folds the topographic based analyses described here may be used to objectively delineate landslide features generate mechanical inferences about landslide behavior and evaluate relatively the recent activity of slides published by elsevier science b v

liquefaction induced lateral spreading in near fault regions during the 1999 chi chi taiwan earthquake we document and analyze incidents of liquefaction induced lateral ground deformation at five sites located in the near fault region of the 1999 chi chi taiwan earthquake each of the lateral spreads involved cyclic mobility of young alluvial soils towards a free face at creek channels in each case the lateral spreading produced relatively modest lateral displacements approximately 10 200 cm in parts of the spreads not immediately adjacent to channel slopes for each site we present displacement vectors across the spread features which are based on mapping performed within three weeks of the earthquake we review the results of detailed subsurface exploration conducted at each site including cone penetration test soundings borings with standard penetration testing and laboratory index tests we back analyze the field displacements using recent empirical and semiempirical models and find that the models generally overestimate the observed ground displacements possible causes of the models overpr

glacial dispersal of till constituents in morainic landforms of different types abstract the range of till landforms covered by the present paper includes cover and ground moraines drumlins and flutings rogen landforms marginal landforms and in addition two landform types the pulju moraine and the sevetti moraine which are not very well known outside finland flow paths and transport distances vary with each landform type in cover moraine areas which are composed of some metres of lodgement till only glacigenic dispersion commonly forms a narrow train with short transport distances a beneficial situation for boulder tracing ground moraine areas with a thick overburden are different however the boulder trains and geochemical anomalies being diluted by the long transport distance a situation which creates problems in prospecting most drumlins and flutings in finland date back to the last deglaciation they are commonly composed of more or less homogeneous sandy till which is mostly distantly derived the situation resembles that of a ground moraine with a thick overburden rogen landforms are commonly layered with the lower part composed of distantly derived material and the surficial part usually of chiefly local material though the overburden can be markedly thick the areas are usually favourable for prospecting pulju moraines consist of both hummocks and winding arcuate ridges a well developed fabric orientation a homogeneous pebble lithology and well rounded clasts are suggestive of basal till with more or less distant derivation of debris even though the surface pattern can resemble ice disintegration features a sevetti moraine forms a train of morainic landforms which includes both parallel ridges and also hummocks and diversely oriented ridges the till making up the landforms is immature and the pebble lithology variable and commonly of very local origin the landform can be considered a beneficial one for prospecting

seismic remote sensing for the earthquake source process and near source strong shaking a case study of the october 16 1999 hector mine earthquake a new methodology to automatically determine the earthquake source process and near source strong ground motions using regional and local distance data was used to study the october 16 1999 hector mine earthquake mw7 1 broadband displacement data were inverted for the seismic moment tensor and to resolve the fault plane ambiguity independent of aftershock location and surface faulting information the identified nnw striking fault plane was used to invert for the distribution of fault slip over a planar surface the slip model was used to predict near fault peak ground velocity which was found to agree well with the trinet shakemap and also with near fault observations that were not available at the time of the initial analysis our method if automated is capable of providing near source strong ground motion information within 30 minutes of the earthquake origin time even in cases where there are few near fault recording instruments

analytical solutions to coupled hm problems to highlight the nonlocal nature of aquifer storage specific storage reflects the volumetric deformation capacity of permeable media classical groundwater hydrology equates elastic storage to medium compressibility plus fluid compressibility times porosity however it is unclear if storage behavior can be represented by a single parameter hydraulic gradients act as body forces that push the medium in the direction of flow causing it to deform instantaneously everywhere i e even in regions where pressure would not have changed according to conventional fluid flow therefore actual deformation depends not only on the mechanical properties of the medium but also on aquifer geometry and on surrounding strata which act like constraints to displacements here we discuss the question and highlight the nonlocal nature of storage i e the volume of water released at a point depends on the poroelastic response over the whole aquifer proper evaluation of transient pressure and water release from storage requires acknowledging the hydromechanical coupling which generally involves the use of numerical methods we propose analytical solutions to the hm problem of fluid injection extraction into finite aquifers with one dimensional or cylindrical geometries we find that pressure response is much faster virtually instantaneous and larger than expected from traditional purely hydraulic solutions when aquifer deformation is restrained whereas the pressure response is reversed i e pressure drop in response to injection when the permeable medium is free to deform these findings suggest that accounting for hydromechanical coupling may be required when hydraulic testing is performed in low permeability media which is becoming increasingly demanded for energy related applications

a methodology for near field tsunami inundation forecasting application to the 2011 tohoku tsunami existing tsunami early warning systems in the world can give either one or a combination of estimated tsunami arrival times heights or qualitative tsunami forecasts before the tsunami hits near field coastlines a future tsunami early warning system should be able to provide a reliable near field tsunami inundation forecast on high resolution topography within a short time period here we describe a new methodology for near field tsunami inundation forecasting in this method a precomputed tsunami inundation and precomputed tsunami waveform database is required after information about a tsunami source is estimated tsunami waveforms at nearshore points can be simulated in real time a scenario that gives the most similar tsunami waveforms is selected as the site specific best scenario and the tsunami inundation from that scenario is selected as the tsunami inundation forecast to test the algorithm tsunami inundation along the sanriku coast is forecasted by using source models for the 2011 tohoku earthquake estimated from gps w phase or offshore tsunami waveform data the forecasting algorithm is capable of providing a tsunami inundation forecast that is similar to that obtained by numerical forward modeling but with remarkably smaller cpu time the time required to forecast tsunami inundation in coastal sites from the sendai plain to miyako city is approximately 3 min after information about the tsunami source is obtained we found that the tsunami inundation forecasts from the 5 min gps 5 min w phase 10 min w phase fault models and 35 min tsunami source model are all reliable for tsunami early warning purposes and quantitatively match the observations well although the latter model gives tsunami forecasts with highest overall accuracy the required times to obtain tsunami forecast from the above four models are 8 min 9 min 14 min and 39 min after the earthquake respectively or in other words 3 min after receiving the source model this method can be useful in developing future tsunami forecasting systems with a capability of providing tsunami inundation forecasts for locations near the tsunami source area

settlements around pumping wells analysis of influential factors and a simple calculation procedure abstract estimated and measured settlements caused by pumping rarely agree several reasons could explain this mismatch including the influence of layering the mechanical parameters used in the predictions or the relationship between settlements and drawdown we analyze the influence of the above issues by investigating the mechanical response of pumped elastic porous media under different conditions a radially symmetric conceptual model is considered and several hydro mechanical simulations are performed varying the boundary conditions the size of the modeled domain and the presence or not of an overlying layer the simplicity of the considered problem allows us to compare our results with existing analytical solutions to identify the role of each variable on pumping settlements and to generalize the results the most relevant results are as follows 1 settlements are proportional to drawdown only outside a circle of radius equal to 0 7 times the thickness of the pumped porous medium inside they are virtually constant which leads to two simple procedures for computing pumping settlements 2 poorly conductive layers located above or below a pumped porous medium with higher hydraulic conductivity reduce and smooth settlements 3 boundary constraints affect the local specific storage coefficient and the displacements occurred 4 the specific storage coefficient evaluated by interpreting pumping tests with the cooper and jacob method 1946 leads to overestimation of the actual young s modulus of the soil the main conclusion is that settlements are less differential than expected near pumping wells still they must always be evaluated acknowledging the nature of layering the boundary constraints and carefully selecting the mechanical parameters of the soil

automated delineation of karst sinkholes from lidar derived digital elevation models abstract sinkhole mapping is critical for understanding hydrological processes and mitigating geological hazards in karst landscapes current methods for identifying sinkholes are primarily based on visual interpretation of low resolution topographic maps and aerial photographs with subsequent field verification which is labor intensive and time consuming the increasing availability of high resolution lidar derived digital elevation data allows for an entirely new level of detailed delineation and analyses of small scale geomorphologic features and landscape structures at fine scales in this paper we present a localized contour tree method for automated extraction of sinkholes in karst landscapes one significant advantage of our automated approach for sinkhole extraction is that it may reduce inconsistencies and alleviate repeatability concerns associated with visual interpretation methods in addition the proposed method has contributed to improving the sinkhole inventory in several ways 1 detection of non inventoried sinkholes 2 identification of previously inventoried sinkholes that have been filled 3 delineation of sinkhole boundaries and 4 characterization of sinkhole morphometric properties we applied the method to fillmore county in southeastern minnesota usa and identified three times as many sinkholes as the existing database for the same area the results suggest that previous visual interpretation method might significantly underestimate the number of potential sinkholes in the region our method holds great potential for creating and updating sinkhole inventory databases at a regional scale in a timely manner

geomorphons a pattern recognition approach to classification and mapping of landforms abstract we introduce a novel method for classification and mapping of landform elements from a dem based on the principle of pattern recognition rather than differential geometry at the core of the method is the concept of geomorphon geomorphologic phonotypes a simple ternary pattern that serves as an archetype of a particular terrain morphology a finite number of 498 geomorphons constitute a comprehensive and exhaustive set of all possible morphological terrain types including standard elements of landscape as well as unfamiliar forms rarely found in natural terrestrial surfaces a single scan of a dem assigns an appropriate geomorphon to every cell in the raster using a procedure that self adapts to identify the most suitable spatial scale at each location as a result the method classifies landform elements at a range of different spatial scales with unprecedented computational efficiency a general purpose geomorphometric map an interpreted map of topography is obtained by generalizing allgeomorphons to a small number of the most common landform elements due to the robustness and high computational efficiency of the method high resolution geomorphometric maps having continental and even global extents can be generated from giga cell dems such maps are a valuable new resource for both manual and automated geomorphometric analyses in order to demonstrate a practical application of this new method a 30 m cell 1 geomorphometric map of the entire country of poland is generated and the features and potential usage of this map are briefly discussed the computer implementation of the method is outlined the code is available in the public domain

stability of rapid finite fault inversion for the 2014 mw6 1 south napa earthquake local seismograms are useful for rapidly reconstructing kinematic finite fault sources but the results often depend not only on the data coverage but also on uncertainties of parameters e g hypocentral location and fault geometry used as a priori information during the inversion an automatic scheme was applied to offline tests for the 2014 south napa earthquake in the case of retrospective full waveform inversions a network with station spacing of 10 km within the epicentral distance of 30 km is able to provide adequate stable key source parameters if the preestimated hypocenter and fault orientation are accurate of 5 km and 15 respectively in simulated real time inversions the magnitude reaches mw6 0 at 13 s and the slip distribution matches that from the retrospective inversion at about 22 28 s after the origin time of the earthquake these results are meaningful for estimating the lead time of a catastrophic seismic event

machine learning based mapping of micro topographic earthquake induced paleo pulju moraines and liquefaction spreads from a digital elevation model acquired through laser scanning abstract the advent of public open source airborne laser scanning produced digital elevation models als dem has provided new perspectives on glacial geomorphology in the nordic countries seismically induced micro topographic paleo landforms can now be identified and mapped throughout the former fennoscandian ice sheet allowing spatial safety assessment for nuclear waste disposal automated machine learning techniques enable recognition of these fine scale geomorphological features efficiently and in a consistent way nationwide the current study focuses on automated recognition of paleo liquefaction spreads and pulju moraines in northern finland geomorphometric variables in different cell sizes were first derived from the 2 m als dem by gabor and principal curvature filtering to emphasize the elevational multi scale texture of these paleo seismic landforms the gabor textural variables were considered as a baseline method and the principal curvature features including maximum and minimum curvature were used because they have previously been proven critical in recognition of concave and convex elongated features both sets of raster variables were then turned into histogram based features and input into a non linear supervised multilayer perceptron early stop committee which is a neural network classifier the leave one out cross validation performance results indicated principal curvature features to be highly successful with 94 accuracy principal curvatures provided a clear improvement to gabor based features which provided significantly lower accuracies between 83 and 85 the study demonstrates the high success of supervised neural network based classification of als dem data and derived textural features capturing the multi scale nature of the micro topographic liquefaction spreads and pulju moraines the approach could be utilized for time efficient mapping of these paleo seismic geomorphologies to complete paleo seismic databases in formerly glaciated regions

distribution and morphology of landslides in northern finland an analysis of postglacial seismic activity abstract the ages and sizes of landslides occurring in seismically active areas can be used to reconstruct the seismic history of the area and estimate the maximum moment magnitudes of past earthquakes here we present a data set of 121 landslides discovered in northern finland that were analyzed for their morphometric characteristics we show that 89 debris slide type landslides in the data set are clustered close to known postglacial faults pgfs and thus provide information on the characteristics of postglacial paleoseismic events by using empirical correlations between the landslide volume area data and earthquake moment magnitude we estimate maximum moment magnitudes m w 6 9 7 7 for postglacial earthquakes in the suasselka isovaara riikonkumpu venejarvi and vaalajarvi areas where earlier estimates based on fault length and displacement have yielded magnitudes varying between m w 6 5 and 7 5 we also show that the landslides in northern finland are located within a radius of 35 km from the closest known pgf and that sizes of the landslides decrease as a function of distance from pgfs hence providing strong empirical evidence for their seismic origin as far as we are aware this is the first use of landside data in quantifying postglacial seismicity within the fennoscandian shield area

automated landslide mapping using spectral analysis and high resolution topographic data puget sound lowlands washington and portland hills oregon abstract landslide inventory maps are necessary for assessing landslide hazards and addressing the role slope stability plays in landscape evolution over geologic timescales however landslide inventory maps produced with traditional methods aerial photograph interpretation topographic map analysis and field inspection are often subjective and incomplete the increasing availability of high resolution topographic data acquired via airborne light detection and ranging lidar over broad swaths of terrain invites new automated landslide mapping procedures we present two methods of spectral analysis that utilize lidar derived digital elevation models of the puget sound lowlands washington and the tualatin mountains oregon to quantify and automatically map the topographic signatures of deep seated landslides power spectra produced using the two dimensional discrete fourier transform and the two dimensional continuous wavelet transform identify the characteristic spatial frequencies of deep seated landslide morphologic features such as hummocky topography scarps and displaced blocks of material spatial patterns in the amount of spectral power concentrated in these characteristic frequency bands highlight past slope instabilities and allow the delineation of landslide terrain when calibrated by comparison with detailed independently compiled landslide inventory maps our algorithms correctly classify an average of 82 of the terrain in our five study areas spectral analysis also allows the creation of dominant wavelength maps which prove useful in analyzing meter scale topographic expressions of landslide mechanics past landslide activity and landslide modifying geomorphic processes these results suggest that our automated landslide mapping methods can create accurate landslide maps and serve as effective objective and efficient tools for digital terrain analysis

digital terrain modelling a review of hydrological geomorphological and biological applications the topography of a catchment has a major impact on the hydrological geomorphological and biological processes active in the landscape the spatial distribution of topographic attributes can often be used as an indirect measure of the spatial variability of these processes and allows them to be mapped using relatively simple techniques many geographic information systems are being developed that store topographic information as the primary data for analysing water resource and biological problems furthermore topography can be used to develop more physically realistic structures for hydrologic and water quality models that directly account for the impact of topography on the hydrology digital elevation models are the primary data used in the analysis of catchment topography we describe elevation data sources digital elevation model structures and the analysis of digital elevation data for hydrological geomorphological and biological applications some hydrologic models that make use of digital representations of topography are also considered

horizontal aquifer movement in a theis thiem confined system the skeletal matrix of an aquifer is known to move laterally toward a discharging well the mechanisms by which it moves relative to the well have been only partially studied in the past examining the relation of drawdown to volume strain for an assumed poroelastic solid has been a common approach by way of contrast the present study examines the relation of the velocity of solids aquifer matrix to their hydraulic driving forces the present approach can be considered darcian and allows the displacement field of the aquifer matrix to be calculated directly a new formulation of the darcy gersevanov law of water flowing relative to moving solids is applied to a theis thiem confined aquifer the aquifer is found to start with a maximum velocity when the pump is turned on and then to decelerate as time progresses dimensionless type curves of horizontal movement of the skeletal matrix are calculated the resulting equation of aquifer deformation is checked against 1 results from alternatively using the standard poroelastic stress strain approach and 2 the fundamental storage equation for transient groundwater flow

three dimensional structure influences on the strong motion wavefield of the 1989 loma prieta earthquake abstract the accurate calculation of ground motions for future large earthquakes depends on detailed knowledge of three dimensional 3d geologic structure and the earthquake source process as well as sufficient computational resources in this article we describe the results of finite difference simulations for the 1989 loma prieta ca earthquake with a 3d seismic velocity model for the san francisco bay region and a heterogeneous slip model of the source additionally we explore the sensitivity of the synthetics to the major geologic structures in the velocity model the san francisco bay region particularly the loma prieta region is a unique area for the study of 3d wave propagation because of the pronounced lateral velocity contrasts across the strike slip faults of the region understanding the effects of such long wavelength structure is doubly important when considering a source located close to such a contrast our simulations show that the lateral velocity contrast across the san andreas fault saf would be expected to substantially affect the propagation of elastic waves radiated from a source in the loma prieta region indeed we find that the refraction of energy by the saf serves to reduce ground motions at stations located along the san francisco peninsula and the quaternary and tertiary alluvial basins of the san francisco bay region are found to amplify and extend the duration of ground motions in santa clara valley livermore valley and san pablo bay we find that the 3d model as currently defined accurately describes the spatial variation of peak ground velocity for frequencies less than 0 5 hz which suggests that this model may be used to estimate ground motions for future earthquake scenarios

seismogeodesy of the 2014 mw6 1 napa earthquake california rapid response and modeling of fast rupture on a dipping strike slip fault real time high rate geodetic data have been shown to be useful for rapid earthquake response systems during medium to large events the 2014 mw6 1 napa california earthquake is important because it provides an opportunity to study an event at the lower threshold of what can be detected with gps we show the results of gps only earthquake source products such as peak ground displacement magnitude scaling centroid moment tensor cmt solution and static slip inversion we also highlight the retrospective real time combination of gps and strong motion data to produce seismogeodetic waveforms that have higher precision and longer period information than gps only or seismic only measurements of ground motion we show their utility for rapid kinematic slip inversion and conclude that it would have been possible with current real time infrastructure to determine the basic features of the earthquake source we supplement the analysis with strong motion data collected close to the source to obtain an improved postevent image of the source process the model reveals unilateral fast propagation of slip to the north of the hypocenter with a delayed onset of shallow slip the source model suggests that the multiple strands of observed surface rupture are controlled by the shallow soft sediments of napa valley and do not necessarily represent the intersection of the main faulting surface and the free surface we conclude that the main dislocation plane is westward dipping and should intersect the surface to the east either where the easternmost strand of surface rupture is observed or at the location where the west napa fault has been mapped in the past

lidar derived dem evaluation of deep seated landslides in a steep and rocky region of japan abstract in steep and rocky terrains their rough surfaces make it difficult to create landslide inventories even with detailed maps images produced from airborne lidar data to provide objective clues in locating deep seated landslides the surface textures of a 5 km2 steepland area in japan was investigated using the eigenvalue ratio and slope filters calculated from a very high resolution lidar derived dem the range of filter values was determined for each of a number of surface features mapped in the field and these included cracked bedrock outcrops coarse colluvial deposits gently undulating surfaces and smooth surfaces recently active slides commonly contained patches of ground in which deposition and erosion occurred together near the erosion front or where cracked bedrock outcrops and coarse colluvial deposits coexisted under a gently undulating surface the characteristic eigenvalue and slope filter values representing this sliding process were applied to maps of the dem derived filter values to extract potential sites of recent landslide activity in addition the relationships between the filter values of deep seated landslides at various stages of evolution within the field mapped area were extended to the entire study area to assess the contribution that landslide evolution makes to change in the landscape as a whole while landslide components made up the steepest as well as the gentlest parts of the landscape depending on their evolutionary stage landslides were constantly coarsened and steepened by progressive erosion probably initiated by river bank erosion at the foot of slopes

post younger dryas fault instability and deformations on ice lineations in finnish lapland abstract the younger dryas phase which occurred between 12 8 and 11 5 ka as a part of the cyclic pattern of global climatic changes was concurrent with maximum fault instability 13 10 ka in the fennoscandian shield ice lineations indicative of glacial streaming toward the younger dryas end moraines ydems may have faced earthquake impacts within the glacial isostatic adjustment gia morphometric analyses for airborne laser scanning als revealed that ice lineations were deformed subglacially and subaerially in finnish lapland the subglacial water outburst flows diagonally eroded the drumlins 50 km from the ydems in utsjoki northern finnish lapland similarly north in the sevetti area 40 km from the ydems a large portion of the ice lineations were entirely distorted by the subglacial squeeze up pulju moraine and liquefaction bowl formations in the interior part of the fennoscandian ice sheet fis in kemijarvi representing onset of an ice stream fan 200 km from the ydems mass flows had reworked the ice lineations based on the electrical sedimentry anisotropy mass flow sediments deviated from the ice flow pattern postglacial liquefaction craters were created on the drumlins in utsjoki and also in kuusamo eastern finnish lapland 70 km from the ydems in russian karelia we interpret these features as indications of paleoseismic events associated with gia

geomorphological criteria for identifying pleistocene ice streams ice streams are critical regulatory mechanisms in contemporary ice sheets it has been inferred that they also had a significant effect on the dynamics of former ice sheets subsequently many people have invoked their widespread occurrence from a variety of formerly glaciated areas hypothesised locations however have often outweighed meaningful evidence this paper addresses the problem using the characteristics of contemporary ice streams as a basis for their identification from former ice sheet beds a convergence of knowledge gained from contemporary ice stream research coupled with theories of glacial geomorphology allows several geomorphological criteria to be identified as suggestive signatures of ice stream activity it is envisaged that the geomorphological criteria developed here will introduce a more objective approach to the study of former ice streams the criteria are used to construct conceptual land system models of the beds of former ice streams and it is hoped such models can provide an observational template upon which hypotheses of former ice streams can be better based

a reinvestigation of the analytical solution for drawdown distributions in a finite confined aquifer a finite aquifer is an aquifer in which drawdown variations reflect the influence of the exterior boundary by making use of laplace transform the transient solution for drawdown distributions in a finite confined aquifer surrounded by constant head boundary is reinvestigated the development of the solution was facilitated by using the available steady state solution for drawdown distributions in a leaky artisian aquifer with constant leakage the solution obtained consists of the theis solution and other functions which are responsible for the influence of the exterior boundary methods of evaluating the solution are given and results are presented in type curves a time criterion is determined approximating the duration during which an ideal aquifer i e the aquifer is homogeneous isotropic and of uniform thickness can property be analyzed as an infinite one this relationship interrelates time with the given hydrogeological properties

postglacial rebound and fault instability in fennoscandia summary the best available rebound model is used to investigate the role that postglacial rebound plays in triggering seismicity in fennoscandia the salient features of the model include tectonic stress due to spreading at the north atlantic ridge overburden pressure gravitationally self consistent ocean loading and the realistic deglaciation history and compressible earth model which best fits the sea level and ice data in fennoscandia the model predicts the spatio temporal evolution of the state of stress the magnitude of fault instability the timing of the onset of this instability and the mode of failure of lateglacial and postglacial seismicity the consistency of the predictions with the observations suggests that postglacial rebound is probably the cause of the large postglacial thrust faults observed in fennoscandia the model also predicts a uniform stress field and instability in central fennoscandia for the present with thrust faulting as the predicted mode of failure however the lack of spatial correlation of the present seismicity with the region of uplift and the existence of strike slip and normal modes of current seismicity are inconsistent with this model further unmodelled factors such as the presence of high angle faults in the central region of uplift along the baltic coast would be required in order to explain the pattern of seismicity today in terms of postglacial rebound stress the sensitivity of the model predictions to the evects of compressibility tectonic stress viscosity and ice model is also investigated for sites outside the ice margin it is found that the mode of failure is sensitive to the presence of tectonic stress and that the onset timing is also dependent on compressibility for sites within the ice margin the evect of earth rheology is shown to be small however ice load history is shown to have larger evects on the onset time of earthquakes and the magnitude of fault instability

reverse water level fluctuations in semiconfined aquifer systems rhade effect abstract pumping tests in semiconfined aquifer systems near dorsten f r g caused anomalous reverse water level fluctuations in observation wells tapping the overlying confining bed aquitard at different depths multilevel piezometer whenever water is pumped from a well that is screened in the aquifer of the halterner sande the piezometric surface in the aquitard bottroper mergel rises after that increase the water level falls according to the drawdown of head within the pumped aquifer noordbergum effect according to verruijt 1969 conversely the piezometric surface in the aquitard falls whenever the pump is shut off rhade effect the anomalous water level reactions propagate with decreasing amplitude from the aquifer aquitard boundary to the top of the semipermeable layer such water level fluctuations swelling effects may be explained by the capability of a water saturated compacted material to change volume when subjected to sudden pressure changes on a practical basis the noordbergum and rhade effects must be taken into consideration for evaluating long term changes in chemical and hydraulic properties in pumped semiconfined aquifer systems

landslide inventory maps new tools for an old problem landslides are present in all continents and play an important role in the evolution of landscapes they also represent a serious hazard in many areas of the world despite their importance we estimate that landslide maps cover less than 1 of the slopes in the landmasses and systematic information on the type abundance and distribution of landslides is lacking preparing landslide maps is important to document the extent of landslide phenomena in a region to investigate the distribution types pattern recurrence and statistics of slope failures to determine landslide susceptibility hazard vulnerability and risk and to study the evolution of landscapes dominated by mass wasting processes conventional methods for the production of landslide maps rely chiefly on the visual interpretation of stereoscopic aerial photography aided by field surveys these methods are time consuming and resource intensive new and emerging techniques based on satellite airborne and terrestrial remote sensing technologies promise to facilitate the production of landslide maps reducing the time and resources required for their compilation and systematic update in this work we first outline the principles for landslide mapping and we review the conventional methods for the preparation of landslide maps including geomorphological event seasonal and multi temporal inventories next we examine recent and new technologies for landslide mapping considering i the exploitation of very high resolution digital elevation models to analyze surface morphology ii the visual interpretation and semi automatic analysis of different types of satellite images including panchromatic multispectral and synthetic aperture radar images and iii tools that facilitate landslide field mapping next we discuss the advantages and the limitations of the new remote sensing data and technology for the production of geomorphological event seasonal and multi temporal inventory maps we conclude by arguing that the new tools will help to improve the quality of landslide maps with positive effects on all derivative products and analyses including erosion studies and landscape modeling susceptibility and hazard assessments and risk evaluations

a semi automated method for mapping glacial geomorphology tested at breiðamerkurjokull iceland abstract despite advances in data collection and analytical software mapping of glacial geomorphology is still largely achieved through manual techniques manual mapping is a relatively slow inefficient and potentially subjective process particularly given the extensive spatial coverage of remotely sensed datasets thus glacial geomorphic mapping would benefit from semi automated techniques able to map large areas quickly and efficiently here we develop novel semi automated techniques for mapping glacial geomorphology based on lidar derived data collected from brei amerkurjokull iceland using object based image analysis obia the landforms classified were moraines eskers flutes drumlins and glacio fluvial outwash several land surface parameters lsps were calculated during image segmentation and analysis representing the characteristics of the landforms of interest the segmentation and classification routines were developed in matlab whereas most attempts so far have used specialised obia software our techniques utilised exploratory data analysis where statistical groupings within the data define different landform types accuracy was assessed against a reference map derived using traditional manual mapping techniques landforms were classified to an overall accuracy of 77 our semi automated mapping techniques should with further algorithm development be applicable using other datasets commonly used in palaeo glaciology such as radar derived elevation data and swath bathymetry

high resolution dems in the study of rainfall and earthquake induced landslides use of a variable window size method in digital terrain analysis abstract we undertake digital terrain analyses of rainfall and earthquake induced landslides in japan using high resolution orthoimagery and light detection and ranging lidar dems our aims are twofold to demonstrate an effective method for dealing with high resolution dems which are often too detailed for landslide assessments and to evaluate the topographic differences between rainfall and earthquake induced landslides the study areas include the izumozaki 1961 and 2004 heavy rainfalls niihama 2004 heavy rainfalls houfu 2009 heavy rainfalls and hanokidachi kurikoma dam regions the 2008 m 7 2 iwate miyagi nairiku earthquake the study areas include 7 106 landslides in these five regions we use two topographic attributes the slope gradient and the laplacian calculated from dems in varying window sizes the hit rates for statistical prediction of landslide cells through discriminant analyses are calculated using the two topographic attributes as explanatory variables and the landslide inventory data as the dependent variable in cases of surface failure the hit rates are found to diminish when the window size of the topographic attributes is too large or too small indicating that an optimal scale factor is key in assessing shallow landslides the representative window sizes are approximately 30 m for shallow landslides the optimal window size may be directly related to the average size of landslides in each region we also find a stark contrast between rainfall and earthquake induced landslides rainfall induced landslides are always most common at a slope gradient of 30 but the frequency of earthquake induced landslides increases exponentially with slope gradient we find that the laplacian i e the attributes of surface convexity and concavity and the slope gradient are both important factors for rainfall induced landslides whereas earthquake induced landslides are influenced mainly by slope steepness

visualization of lidar derived relief models for detection of archaeological features abstract this paper presents visualisation techniques of high resolution digital elevation models dems for visual detection of archaeological features the methods commonly used in archaeology are reviewed and improvements are suggested one straightforward technique that has so far not been used in archaeology the shift method is presented the main purpose of this article is to compare and evaluate different visualisation methods two conclusions have been reached where a single method must be chosen for printing or producing digital images for non professionals the use of sky view factor or slope gradient is endorsed both presented in greyscale otherwise interpreters should choose different techniques on different terrain types shift on flat terrain sky view factor on mixed terrain slope gradient on sloped terrain and sky view factor preferably as a composite image with slope gradient on rugged terrain

quantitative analysis of land surface topography land surface topography significantly affects the processes of runoff and erosion a system which determines slope aspect and curvature in both the down slope and across slope directions is developed for an altitude matrix also the upslope drainage area and maximum drainage distance are determined for every point within the altitude matrix a fortran 66 program performs the analysis

electrical sedimentary anisotropy of landforms adjacent to postglacial faults in lapland abstract postglacial faults pgfs are common sw ne trending features in the northern part of the fennoscandian shield being attributed to former high magnitude mw 7 8 2 earthquakes arvidsson 1996 these are of interest for the long term seismic hazard of deep geological nuclear waste repositories the pgfs are still seismically active and many of the deformation features such as paleolandslides are spatially coextensive within these earthquake zones based on the 14c datings of landslide buried organic materials three postglacial seismic episodes 9 7 11 5 6 and 1 3 1 8 ky ago have been found in western finnish lapland because the model predictions by wu et al 1999 suggested that the onset of fault instability started at 15 ky and that the maximum fault instability was reached at 13 10 ky in fennoscandia we postulate that not only subaerial but also subglacial types of deformations may have been associated with the past seismic events here we present lidar dem observations and sediment electromagnetic anisotropy data on the landforms such as the rim ridged arcuate pulju moraine kujansuu 1967 roundish liquefaction bowls postdepositional liquefaction deformations on streamlined landforms as well as hummocky ridge fields of massflow sediments the sediments in the pulju moraine and massflow ridges displayed clear anisotropy indicating lateral transportation in subglacial wet based environment instead sediments in the bowl shaped morphologies next to pgfs and deformed ice stream flutings tended to be isotropic suggesting postdepositional and vertical liquefaction processes based on the lidar morphology and sedimentary anisotropy data these landforms may be linked to past earthquakes

real time centroid moment tensor determination for large earthquakes from local and regional displacement records summary we present an algorithm to rapidly determine the moment tensor and centroid location for large earthquakes employing local and regional real time high rate displacement records from gps the algorithm extracts the coseismic offset from the displacement waveforms and uses the information to invert for the moment tensor the green s functions for a layered earth are obtained numerically from open source code edgrn to determine the centroid multiple inversions are simultaneously performed within a grid of inversion nodes and the node with the smallest misfit is then assigned the centroid location we show results for two large earthquakes replayed in simulated real time mode using recorded 1 hz gps displacements the 2003 mw 8 3 tokachi oki and the 2010 mw 7 2 el mayor cucapah earthquakes we demonstrate that it is feasible to obtain accurate cmt solutions within the first 2 3 min after rupture initiation without any prior assumptions on fault characteristics demonstrating an order of magnitude improvement in latency compared to existing seismic methods for the two earthquakes studied this methodology is useful for rapid earthquake response tsunami prediction and as a starting point for rapid finite fault modelling

the 2014 m w 6 0 napa earthquake california observations from real time gps enhanced earthquake early warning recently progress has been made to demonstrate feasibility and benefits of including real time gps rtgps in earthquake early warning and rapid response systems most concepts however have yet to be integrated into operational environments the berkeley seismological laboratory runs an rtgps based finite fault inversion scheme in real time this system g larms detected the 2014 mw 6 0 south napa earthquake in california we review g larms performance during this event and 13 aftershocks and present rtgps observations and real time modeling results for the main shock the first distributed slip model and magnitude estimates were available 24 s after the event origin time which after optimizations was reduced to 14 s 8s s wave travel time 6 s data latency g larms solutions for the aftershocks that had no measurable surface displacements demonstrate that in combination with the seismic early warning magnitude m w 6 0 is our current resolution limit

fennoscandian earthquakes whole crustal rupturing related to postglacial rebound local and regional earthquake locations provide seismic evidence that large shield earthquakes have occurred in northern fennoscandia these paleoearthquakes with fault lengths of up to 160 kilometers and average displacements of up to 15 meters were triggered by nonisostatic compressive stresses caused by the removal of the ice at the end of the last deglaciation the fennoscandian faults were probably formed by single events that ruptured through most of the crust the largest event moment magnitude mw 8 2 was larger than other known stable continent earthquakes outside failed rifts or extended crust

multiscale analysis of topographic surface roughness in the midland valley scotland surface roughness is an important geomorphological variable which has been used in the earth and planetary sciences to infer material properties current past processes and the time elapsed since formation no single definition exists however within the context of geomorphometry we use surface roughness as an expression of the variability of a topographic surface at a given scale where the scale of analysis is determined by the size of the landforms or geomorphic features of interest six techniques for the calculation of surface roughness were selected for an assessment of the parameter s behavior at different spatial scales and data set resolutions area ratio operated independently of scale providing consistent results across spatial resolutions vector dispersion produced results with increasing roughness and homogenization of terrain at coarser resolutions and larger window sizes standard deviation of residual topography highlighted local features and did not detect regional relief standard deviation of elevation correctly identified breaks of slope and was good at detecting regional relief standard deviation of slope sdslope also correctly identified smooth sloping areas and breaks of slope providing the best results for geomorphological analysis standard deviation of profile curvature identified the breaks of slope although not as strongly as sdslope and it is sensitive to noise and spurious data in general sdslope offered good performance at a variety of scales while the simplicity of calculation is perhaps its single greatest benefit

surficial geology indicates early holocene faulting and seismicity central sweden in sweden knowledge of the location and timing of glacially induced faulting and seismicity is critical to effective engineering of a long term nuclear disposal facility to improve understanding and modeling of the complex ice induced and tectonic stresses associated with glacially induced faulting field studies detailing the location and timing of movement of such structures are required although the fault has not been confirmed in the bedrock multi proxy surficial geologic evidence indicates that the recently discovered scarp in bollnas is such a structure machine excavated trenches across the scarp reveal landsliding down the scarp and in one location faulted and vertically offset fine grained glacial sediments the presence of water escape structures in trenches excavated on a topographic high strongly suggests a co seismic origin derived from earthquake magnitudes 5 5 numerous landslides in till exist in the region as well four slopes with landslides were examined in detail and the factors of safety for these slopes indicate stable conditions and suggest a seismic trigger basal radiocarbon dates from peat bogs located stratigraphically above the landslides provide minimum limiting ages for the co seismic landslides the oldest date indicates sliding prior to 10 180 calendar years before the present the proposed bollnas fault is 400 km south of the so called lapland fault province to date it is the southernmost confirmed glacially induced fault in sweden the results of this study are consistent with existing modeling results that indicate fault instability in this region of central sweden following deglaciation

new insights into magnetic derivatives for structural mapping magnetic and gravity derivatives can be likened to seismic attributes in that they can help define estimate the physical properties of the source structure causing the anomaly this contribution looks at the tilt derivative first reported in 1994 and more recently used to derive the local wavenumber 1997 we will show that the combination of the tilt derivative and its total horizontal derivative are highly suitable for mapping shallow basement structure and mineral exploration targets and that they have distinct advantages over many conventional derivatives we provide the simple theory behind the derivatives use a range of simple 2d models to illustrate their response and apply them to mapping a mineral target in namibia

hummocky moraine landscape on jaeren sw norway implications for glacier dynamics during the last deglaciation abstract the jaeren area sw norway can topographically be divided in two regions lagjaeren and hogjaeren hogjaeren is a plateau 120 m a s l covered by quaternary sediments the stratigraphically youngest deposit is a sandy diamicton which accumulated in ridges and hummocks during the last deglaciation this hummocky moraine landscape has previously been interpreted as the record of a stagnant glacier detailed morphological mapping and sedimentological investigations have revealed that various glacigenic elements exist and dominate different areas of the hogjaeren plateau glacigenic elements formed by an active wet based glacier characterize the southern central hummocky area and include marginal moraine ridges and drumlins while circular moraine ridges and glaciofluvial features formed in a stagnant glacial regime dominate the northern central hummocky area the distribution of glacigenic elements within the hummocky moraine landscape shows that active and stagnant ice coexisted on hogjaeren during the last deglaciation and that actively flowing ice was focused through eastward extending valleys it is not possible to determine whether ice flow was kept active in the southern area throughout the deglaciation or if the glacier was reactivated a possible readvance is suggested to have happened simultaneous to a readvance previously suggested based on the morphology on lagjaeren

application of real time gps to earthquake early warning 1 we explore the use of real time high rate gps displacement data for earthquake early warning using 1 hz displacement waveforms from the april 4 2010 mw 7 2 el mayor cucapah earthquake we compare these data to those provided by the broadband velocity and accelerometer instrumentation of the southern california seismic network the unique information provided by the gps based displacement timeseries is the permanent static displacement using a simple algorithm that can be applied in real time we extract the static offset shortly after the s wave arrival around the time of the observed peak shaking at the same site and before shaking at more distant locations these data can be used as they become available to provide a robust estimate of the earthquake magnitude which ranges from 6 8 to 7 0 in this case we therefore conclude that real time high rate gps can provide a useful and independent assessment of earthquake magnitude for the purpose of earthquake early warning and real time earthquake information systems in general including tsunami warning systems

an updated method for estimating landslide event magnitude summary statistics derived from the frequency area distribution fad of inventories of triggered landslides allows for direct comparison of landslides triggered by one event e g earthquake rainstorm with another such comparisons are vital to understand links between the landslide event and the environmental characteristics of the area affected this could lead to methods for rapid estimation of landslide event magnitude which in turn could lead to estimates of the total triggered landslide area previous studies proposed that the fad of landslides follows an inverse power law which provides the basis to model the size distribution of landslides and to estimate landslide event magnitude mls which quantifies the severity of the event in this study we use a much larger collection of earthquake induced landslide eqil inventories n 45 than previous studies to show that size distributions are much more variable than previously assumed we present an updated model and propose a method for estimating mls and its uncertainty that better fits the observations and is more reproducible robust and consistent than existing methods we validate our model by computing mls for all of the inventories in our dataset and comparing that with the total landslide areas of the inventories we show that our method is able to estimate the total landslide area of the events in this larger inventory dataset more successfully than the existing methods 2018 the authors earth surface processes and landforms published by john wiley sons ltd

application of real time gps to earthquake early warning in subduction and strike slip environments 1 we explore the application of gps data to earthquake early warning and investigate whether the coseismic ground deformation can be used to provide fast and reliable magnitude estimations and ground shaking predictions we use an algorithm to extract the permanent static offset fromgps displacement time series and invert for theslip distribution on the fault plane which is discretized into a small number of rectangular patches we developed a completely self adapting strategy in which the initial fault plane model is built based on a quick approximate magnitude estimation and is then allowed to increase in size based on the evolutionary magnitude estimation resulting from the slip inversion two main early warning outputs are delivered in real time magnitude and the along strike extent of the rupture area these are finally used to predict the expected ground shaking due to the finite source we tested the proposed strategy by simulating real time environments for three earthquakes for themw9 0 2011 tohoku oki earthquake our algorithm provides the first magnitude estimate of 8 2 at 39 s after the origin time and then gradually increases to 8 9 at 120 s the estimated rupture length remains constant from the outset at 360 km for the mw 8 3 2003 tokachi oki earthquake the initial magnitude estimate is 8 5 at 24 s and drops to 8 2 at 40 s with a rupture length of 290 km finally for the mw 7 2 2010 el mayor cucapah earthquake the magnitude estimate is 7 0 from the outset with a rupture length of 140 km the accuracy of the ground shaking prediction using the gps based magnitude and finite extent is significantly better than existing seismology based point source approaches this approach would also facilitate more rapid tsunami warnings

diversity of solutions of the problem of earthquake faulting inversion application to sh waves for the great 1989 macquarie ridge earthquake abstract we use the sh waves generated by the great 1989 macquarie ridge earthquake to investigate the non uniqueness of the inverse problem of earthquake faulting the details of the method of linear programming developed for this problem of solution of a constrained set of equations is described protective measures necessary to remove loss of accuracy when solving the problem for large numbers of unknowns and constraints are developed it is shown that solutions which look very different fit the data almost equally well a method is presented for choosing solutions with desirable properties e g with the most uniformly distributed moment along the fault or with the most concentrated moment release on the fault from among available solutions the results show that the data may equally well be interpreted as representing an asperity model of faulting or a propagating crack model of faulting the common feature of all the models is that the hypocentral region is a region of low moment release with regions of higher release being located to its northeast and its southwest along the fault clearly this earthquake did not initiate by the rupture of an asperity

automatic imaging of earthquake rupture processes by iterative deconvolution and stacking of high rate gps and strong motion seismograms by combining the complementary advantages of conventional network inversion and backprojection methods we have developed an iterative deconvolution and stacking ids approach for imaging earthquake rupture processes with near field complete waveform data this new approach does not need any manual adjustment of the physical empirical constraints such as restricting the rupture time and duration and smoothing the spatiotemporal slip distribution therefore it has the ability to image complex multiple ruptures automatically the advantages of the ids method over traditional linear or nonlinear optimization algorithms are demonstrated by the case studies of the 2008 wenchuan and 2011 tohoku earthquakes for such large earthquakes the ids method is considerably more stable and efficient than previous inversion methods additionally the robustness of this method is demonstrated by comprehensive synthetic tests indicating its potential contribution to tsunami and earthquake early warning and rapid response systems it is also shown that the ids method can be used for teleseismic waveform inversions for the two major earthquakes discussed here the ids method can provide without tuning any physical or empirical constraints teleseismic rupture models consistent with those derived from the near field gps and strong motion data

supervised classification of types of glaciated landscapes using digital elevation data abstract automated approaches for identifying different types of glaciated landscapes using digitally processed elevation data were evaluated we tested the ability of geomorphic measures e g elevation relative relief roughness and slope gradient derived from digital elevation models dems to differentiate glaciated landscapes using maximum likelihood classification and artificial neural networks ann the automated methods were trained and validated using an existing quaternary geology map and a manual interpretation of the contour data portrayed on topographic quadrangles the need for such methods arises from efforts to classify types of landscapes e g ecoregions in michigan one fundamental control of the landscape structure in michigan including soil type and vegetation is the underlying sedimentary and landform assemblages produced by an array of glacial processes during the waning phase of the pleistocene traditional methods for identifying different landscapes e g ice contact landscapes stagnation landscapes have relied on printed topographic maps and have been very effective but time consuming the maps resulting from the four supervised classification trials had between 51 and 61 agreement with the original quaternary geology map the output from the maximum likelihood classification had slightly higher agreements than the output from the neural net which is attributed to the generalization inherent in the quaternary geology map compared with the nature of the classifier for the neural net the neural net however identifies significant detail and non linear relationships between classification inputs and output classes future work should incorporate a map of soils into the classification

fennoscandian palaeoglaciology reconstructed using a glacial geological inversion model the evolution of ice sheet configuration and flow pattern in fennoscandia through the last glacial cycle was reconstructed using a glacial geological inversion model i e a theoretical model that formalises the procedure of using the landform record to reconstruct ice sheets the model uses mapped flow traces and deglacial melt water landforms as well as relative chronologies derived from cross cutting striae and till lineations as input data flow trace systems were classified into four types i time transgressive wet bed deglacial fans ii time transgressive frozen bed deglacial fans iii surge fans and iv synchronous non deglacial event fans using relative chronologies and aggregation of fans into glaciologically plausible patterns a series of ice sheet configurations at different time slices was erected a chronology was constructed through correlation with dated stratigraphical records and proxy data reflecting global ice volume geological evidence exists for several discrete ice sheet configurations centred over the scandinavian mountain range during the early weichselian the build up of the main weichselian fennoscandian ice sheet started at approximately 70 ka and our results indicate that it was characterised by an ice sheet with a centre of mass located over southern norway this configuration had a flow pattern which is poorly reproduced by current numerical models of the fennoscandian ice sheet at the last glacial maximum the main ice divide was located overthe gulf of bothnia a major bend in the ice divide was caused by outflow of ice to the northwest over the lowest part of the scandinavian mountain chain widespread areas of preserved pre late weichselian landscapes indicate that the ice sheet had a frozen bed core area which was only partly diminished in size by inward transgressive wet bed zones during the decay phase

pattern recognition of lidar data and sediment anisotropy advocate a polygenetic subglacial mass flow origin for the kemijarvi hummocky moraine field in northern finland abstract object based image analysis and supervised machine learning on a digital elevation model derived from airborne laser scanning data were conducted to assess the aggregate raw material potential over the kemijarvi hummocky moraine field in finnish lapland geomorphometric analysis revealed surface stoniness to be diagnostic of moraine hummocks it was utilized to detect true moraine hummocks from among the potential hummocks delineated using object based image analysis with logistic regression of curvature features derived from the digital elevation model area under the receiver operating characteristics curve auc 0 77 based on the electrical sedimentary anisotropy data the kemijarvi moraine is polygenetic such that the ridges are diagonally and erosionally fluted from sector 280 290 on their surfaces while the ridge cores are deposited from the nw from sector 310 340 the cores are composed of infill gravels and crudely stratified diamict sequences we consider the core of the kemijarvi hummocky moraine field to represent pre existing early weichselian subglacial ridges rather than being generated through monogenetic late weichselian compressional shearing and stacking frozen bed extension or bed ribbing instability mechanisms as presented for ribbed moraines that are transverse to ice flow recently evidence has been presented of multiple slip events earthquakes with moment magnitudes mw 6 7 7 0 up ice from kemijarvi we therefore propose that the genesis of the hummocks may be associated with past early weichselian fault instability within glacio isostatic adjustment s which was able to generate subglacial water bodies possibly lakes and saturated materials that were forced towards the se based on this new geomorphological evidence from mapping using a digital elevation model derived from airborne laser scanning data and azimuthal conductivity surveys combined with the reinterpretation of previously presented geophysics and sedimentological observations we suggest the kemijarvi hummocky moraine field to be reconsidered as the kemijarvi subglacial mass flow field which holds significant potential for construction aggregate materials

rupture history of 2014 mw 6 0 south napa earthquake inferred from near fault strong motion data and its impact to the practice of ground strong motion prediction the spatiotemporal rupture history of the 2014 south napa earthquake is constrained using near fault strong motion records an aggressive source parameterization with 1372 subfaults is adopted to match the signals in the transverse components up to 4 hz the result reveals that the rupture of the napa earthquake initiated at a depth of 9 84 km and propagated mainly to north northwest nnw and updip on a 13 km long fault patch a gradual increase in average rise time when the rupture propagates to shallower depth is observed however it is the rupture of a small mw 4 9 isolated and high stress drop fault patch that excited the largest ground acceleration at stations south of the epicenter such fine scale rupture heterogeneity shall be considered during seismic hazard analysis

a time domain inversion technique for the tempo spatial distribution of slip on a finite fault plane with applications to recent large earthquakes in the tibetan plateau a time domain inversion technique is proposed to invert for the tempo spatial distribution of slip on an earthquake fault plane this technique is based on the idea that a finite fault plane can be divided into several subfaults each of which can be treated as a point source and that the source time function stf of the finite fault is the weighted sum of the stfs of all the subfaults this technique is applied to deduce the source processes of three recent large earthquakes in the qinghai xizang tibetan plateau the 1990 april 26 gonghe qinghai earthquake ms6 9 ruptured on a fault plane with a strike of 113 a dip of 68 and a rake of 89 the fault has a length of 45 km a width of 15 km and a total moment release of 9 4 1018 n m the rupture initiated at the wnw end of the fault and propagated unilaterally towards the ese end of the fault in total the rupturing lasted for 45 s and was divided into two episodes the first 9 s long and the second 16 s long with 20 s quiescence in between there are two distinct rupture regions nuclei on the fault plane these two nuclei with maximum slips of about 62 and 55 cm are about 25 km apart in the wnw ese direction the 1996 february 3 lijiang yunnan earthquake ms7 0 has a focal mechanism with a strike of 157 a dip of 48 and a rake of 102 the earthquake fault is about 45 km with a width of 20 km and a total moment release of 9 8 1018 n m the total duration of the rupture was 16 s is divided into two episodes the first 8 5 s long and the second 7 5 s long the inverted final slip distribution of the lijiang earthquake also shows two nuclei one nucleus with a maximum slip of 40 cm is located on the nnw portion of the fault at a shallower depth and the other with a maximum slip of 50 cm is located on the sse portion of the fault at a greater depth the 1997 november 8 mani xizang tibet earthquake ms7 9 has a focal mechanism with a strike of 250 a dip of 88 and a rake of 19 and a moment release of 3 4 1020 n m the total duration of the rupture was about 15 s the inverted final slip distribution of the mani earthquake shows three nuclei on the fault plane the first nucleus with a maximum slip of 956 cm is located at the wsw end of the fault at 10 km in depth the second with a maximum slip of 743 cm is located at the ene end of the fault 55 km away from the wsw end of the fault and at 35 km depth the third with a maximum slip of 1060 cm is about 30 km away from the wsw end of the fault and at about 40 km depth these three nuclei form a total rupture area of about 70 km in length and 60 km in depth

supervised landform classification of northeast honshu from dem derived thematic maps this paper proposes a quantitative method to classify landforms using four morphometric parameters from dem derived thematic raster maps of slope and topographic openness because the different surficial processes and stages in the evolution of slopes create landscapes with different shapes these parameters may lead to a genetic interpretation of topography the raster maps of slope and topographic openness were constructed for northeast honshu japan from 50 m dems the mean and standard deviation of morphometric parameters within a 3050m by 3050m moving window on the raster maps were calculated the results for some training areas show that constructional depositional and erosional landforms with different relief have different morphometric characteristics a supervised landform classification for northeast honshu using the knowledge from the training areas revealed a ladder geomorphological structure composed of high mountains ranges and volcanoes the close relationship between the ladder geomorphological structure and volcano distribution indicates that the structure reflects the magmatic plumbing system from the upper mantle to the crust of the northeast honshu arc

use of lidar derived images for mapping old landslides under forest large deep seated landslides are common features in the flemish ardennes belgium as most of these old 100 years landslides are located under forest in this hilly region aerial photograph interpretation is not an appropriate landslide mapping method this study tested the potential of lidar light detection and ranging images for mapping old landslides under forest landslide inventory maps were created for a 125 km2 area by applying the expert knowledge of seven geomorphologists to lidar derived hillshade slope and contour line maps in a gis environment each of the seven lidar based landslide inventories was compared i with the other six ii with a detailed field survey based inventory and iii with a comparable study in which topographic data were extracted from a topographical map the combination of the percentage of field landslides indicated by an expert and the percentage of positional discrepancies expressed in terms of positional mismatch were used to evaluate the quality of the lidar based inventory maps high quality lidar derived landslide inventory maps contain more than 70 per cent of the landslides mapped during the field survey and have positional discrepancies smaller than 70 per cent when compared with the field survey based inventory map four experts and the combination map of all experts satisfied these criteria together the seven experts indicated all landslides mapped in the field importantly lidar enabled the experts to find ten new landslides and to correct the boundaries of eleven of the 77 landslides mapped during the field survey hence this study showed that large scale lidar derived maps analysed by experienced geomorphologists can significantly improve field survey based inventories of landslides with a subdued morphology in hilly regions copyright 2006 john wiley sons ltd

comparing landslide inventory maps landslide inventory maps are effective and easily understandable products for both experts such as geomorphologists and for non experts including decision makers planners and civil defense managers landslide inventories are essential to understand the evolution of landscapes and to ascertain landslide susceptibility and hazard despite landslide maps being compiled every year in the word at different scales limited efforts are made to critically compare landslide maps prepared using different techniques or by different investigators based on the experience gained in 20 years of landslide mapping in italy and on the limited literature on landslide inventory assessment we propose a general framework for the quantitative comparison of landslide inventory maps to test the proposed framework we exploit three inventory maps the first map is a reconnaissance landslide inventory prepared for the umbria region in central italy the second map is a detailed geomorphological landslide map also prepared for the umbria region the third map is a multi temporal landslide inventory compiled for the collazzone area in central umbria results of the experiment allow for establishing how well the individual inventories describe the location type and abundance of landslides to what extent the landslide maps can be used to determine the frequency area statistics of the slope failures and the significance of the inventory maps as predictors of landslide susceptibility we further use the results obtained in the collazzone area to estimate the quality and completeness of the two regional landslide inventory maps and to outline general advantages and limitations of the techniques used to complete the inventories

seasonality and increasing frequency of greenland glacial earthquakes some glaciers and ice streams periodically lurch forward with sufficient force to generate emissions of elastic waves that are recorded on seismometers worldwide such glacial earthquakes on greenland show a strong seasonality as well as a doubling of their rate of occurrence over the past 5 years these temporal patterns suggest a link to the hydrological cycle and are indicative of a dynamic glacial response to changing climate conditions

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

coupled multiphase poroelastic analysis of reservoir depletion including surrounding strata field observations suggest that although pressure depletion is a local process that only occurs inside aquifers or reservoirs it results in volume changes that trigger a redistribution of effective stresses in a more extensive domain which involves the entire overburden and surrounding rocks extending out to considerable distances a tabular petroleum reservoir in an infinite or semi infinite domain is viewed as a macroscopic displacement discontinuity allowing use of the efficient displacement discontinuity mathematical method to calculate stresses and displacements that arise due to pressure changes a three dimensional 3 d finite element method fem using a multiphase poroelastic formulation is applied to the reservoir by coupling the displacement discontinuity and fems a 3 d large scale multiphase poroelastic reservoir can be simulated within an infinite or semi infinite domain numerical examples are given and results indicate that the influence of the surrounding rocks is an essential coupling factor for the analysis of multiphase flow induced pressure changes saturation evolution and reservoir deformation arising from injection or production activities

real time high rate co seismic displacement from ambiguity fixed precise point positioning application to earthquake early warning 1 nowadays more and more high rate real time gps data become available that provide a great opportunity to contribute to earthquake early warning eew system in terms of capturing regional surface displacements as an independent information source useful for promptly estimating the magnitude of large destructive earthquake in our study we demonstrate the performance of the real time ambiguity fixed precise point positioning ppp approach using 5 hz gps data collected during el mayor cucapah earthquake mw 7 2 4 april 2010 the ppp based displacements show to agree with accelerometer based displacement at centimeter level the key for successfully obtaining high precision displacements is the efficient ambiguity resolution ppp with ambiguity fixing can result in correct permanent co seismic offsets and correct recovery of moment magnitude and fault slip inversion at levels comparable to post processing

mathematical model for regional land subsidence due to pumping 2 integrated aquifer subsidence equations for vertical and horizontal displacements a mathematical model for regional subsidence due to pumping from an aquifer is developed on the basis of biot s work on coupled three dimensional consolidation following biot s work on threedimensional consolidation with coupling between mass conservation and equilibrium equations a mathematical model for regional subsidence due to pumping from an aquifer is developed by averaging the three dimensional model over the thickness of the aquifer and assuming conditions of plane stress both vertical land subsidence and horizontal displacements as functions of plane coordinates and time can be estimated by solving the model equations for a given confined or leaky confined aquifer an analytical solution is presented for the special case of a single well pumping from an infinite homogeneous isotropic aquifer the solution provides estimates of changes in averaged over the vertical values of piezometric head vertical subsidence and horizontal displacement the results indicate that under the conditions of the studied case of radial flow the solution for piezometric head is identical to the one obtained by noncoupled models furthermore half the volume strain is produced by vertical subsidence while the other half by the horizontal displacement hence the vertical subsidence is only approximately half the value obtained in noncoupled models which neglect horizontal displacement a numerical example demonstrates these conclusions

toward earthquake early warning in northern california 1 earthquake early warning systems are an approach to earthquake hazard mitigation which takes advantage of the rapid availability of earthquake information to quantify the hazard associated with an earthquake and issue a prediction of impending ground motion prior to its arrival in populated or otherwise sensitive areas one such method earthquake alarm systems elarms has been under development in southern california and more recently in northern california event magnitude is estimated using the peak amplitude and the maximum predominant period of the initial p wave elarms incorporates ground motion prediction equations and algorithms from shakemap for prediction of ground motions in advance of the s wave arrival the first peak ground motion estimates are available 1 s after the first p wave trigger and are updated each second thereafter for the duration of the event the elarms methodology has been calibrated using 43 events ranging in size from ml 3 0 to mw 7 1 that occurred in northern california since 2001 we present the results of this calibration as well as the first implementation of elarms in an automated noninteractive setting and the results of 8 months of noninteractive operation in northern california between february and september 2006 elarms successfully processed 75 events between md 2 86 to mw 5 0 we find that the elarms methodology processed these events reliably and accurately in the noninteractive setting the median warning time afforded by this method is 49 s at the major population centers of the bay area for these events the magnitude estimate is within an average of 0 5 units of the network derived magnitude and the ground motion prediction from elarms is within an average of 0 1 units of the observed modified mercalli intensity

liquefaction limit during earthquakes and underground explosions implications on ground motion attenuation liquefaction of saturated soils and sediments documented during earthquakes shows an empirical relation log r max 2 05 0 10 0 45 m where r max is the liquefaction limit in meters i e the maximum distance from liquefaction site to the hypocenter and m is the earthquake magnitude combining this with an empirical relation between m and the seismic energy of an earthquake we obtain a relation between the liquefaction limit and the seismic energy e a r max the prefactor corresponds to a threshold energy for liquefaction ranging from 0 004 to 0 1 j m3 the exponent ranging from 3 2 to 3 3 implies that the energy density of ground motion attenuates with distance according to 1 r 3 2 3 3 where r is the distance from the hypocenter the value of the threshold energy suggests a preliquefaction degradation of the shear modulus of soils by more than 3 orders of magnitude liquefaction documented during underground explosions is characterized by a threshold energy several orders of magnitude greater than that for liquefaction during earthquakes but shows a similar functional relation between e and r max as that for liquefaction during earthquakes and implies a similar attenuation relation between ground motion energy density and distance

rapid detection and characterization of large earthquakes using quasi finite source green s functions in continuous moment tensor inversion 1 large earthquakes along subduction zones have the potential to generate tsunamis along local coasts as well as traveling far across oceans by continuously inverting for moment tensors we show that it is possible with a single procedure to automatically detect locate and determine source parameters of any earthquake from magnitude 3 5 to larger than 8 located in both the near and far field we find that the detection and characterization of large earthquakes is improved when quasi finite source green s functions are used in a point source moment tensor approach as they represent to some extent the rupture s finiteness and directivity solutions can be obtained within several minutes after the origin time of the earthquake and could therefore be used as part of a near source tsunami early warning system capable of providing tens of minutes of possible warning depending on the distance of the earthquake rupture from the coast

source rupture process of the tecoman colima mexico earthquake of 22 january 2003 determined by joint inversion of teleseismic body wave and near source data the spatial and temporal slip distribution of the tecoman colima mexico earthquake is estimated from near source strong motion and teleseismic body wave data to perform a stable inversion we applied smoothing constraints and determined their optimal relative weights on the observed data using an optimized akaike s bayesian information criterion abic the source parameters are as follows strike dip slip 300 20 93 seismic moment m 2 3 1020 n m source duration 30 sec along strike distance 35 km along dip distance 70 km we found that the rupture process can be divided into three stages the rupture nucleated near the hypocenter stage i then it broke the first asperity centering about 15 km southwest from the epicenter stage ii and the rupture propagated to the northeast and the second asperity was broken stage iii we also estimated the shear stress change due to the rupture process of the mainshock on and around the major fault zone it appears that one cluster of aftershocks for the first 5 days which took place in and adjacent to the zones of stress increased due to the fault rupture during the mainshock but overall correlation between the aftershock location and the stress pattern is not clear manuscript received 14 may 2003

analysis of lidar derived topographic information for characterizing and differentiating landslide morphology and activity abstract this study used airborne laser altimetry lidar to examine the surface morphology of two canyon rim landslides in southern idaho the high resolution topographic data were used to calculate surface roughness slope semivariance and fractal dimension these data were combined with historical movement data global positioning systems gps and laser theodolite and field observations for the currently active landslide and the results suggest that topographic elements are related to the material types and the type of local motion of the landslide weak unconsolidated materials comprising the toe of the slide which were heavily fractured and locally thrust upward had relatively high surface roughness high fractal dimension and high vertical and lateral movement the body of the slide which predominantly moved laterally and consists mainly of undisturbed older canyon floor materials had relatively lower surface roughness than the toe the upper block consisting of a down dropped section of the canyon rim that has remained largely intact had a low surface roughness on its upper surface and high surface roughness along fractures and on its west face unrelated to landslide motion the upper block also had a higher semivariance than the toe and body the topographic data for a neighboring older and larger landslide complex which failed in 1937 are similarly used to understand surface morphology as well as to compare to the morphology of the active landslide and to understand scale dependent processes the morphometric analyses demonstrate that the active landslide has a similar failure mechanism and is topographically more variable than the 1937 landslide especially at scales 20 m weathering and the larger scale processes of the 1937 slide are hypothesized to cause the lower semivariance values of the 1937 slide at smaller scales

glacial earthquakes in greenland and antarctica glacial earthquakes are a new class of seismic events first discovered as signals in long period seismograms recorded on the global seismographic network most of these events occur along the coasts of greenland where they are spatially related to large outlet glaciers glacial earthquakes show a strong seasonality with most events occurring during the late summer the rateofglacial earthquakeoccurrenceincreasedbetween2000and2005 with a stabilization of earthquake frequency at 2003 2004 levels in 2006 2008 recent observations establish a strong temporal correlation between the distinct seismic signals of glacial earthquakes and large ice loss events in which icebergs of cubic kilometer scale collapse against the calving face linking the seismogenic process to the force exerted by these icebergs on the glacier andtheunderlyingsolidearth asuddenchangeinglacierspeedresultsfrom these glacial earthquake calving events seasonal and interannual variations in glacier terminus position account for general characteristics of the temporal variation in earthquake occurrence glacial earthquakes in antarctica are less well studied but they exhibit several characteristics similar to glacial earthquakes in greenland