3 d inhomogeneities in the upper mantle abstract the method developed by aki christofferson and husebye for determining a 3 d seismic image of the earth s interior from the travel time data obtained at a 2 d array has been applied to seventeen arrays around the world by various authors the most outstanding results from these works are that small scale lateral velocity anomalies exist in the lower crust and upper mantle everywhere studied the reality of these deep seated anomalies is supported by 1 1 significant reduction of residual variance 2 2 resolution analysis for decoupling from shallower anomalies and 3 3 error analysis for the significance of anomalies in this paper we try to strengthen the credibility of these deep seated anomalies by drawing attention to those found where they were expected namely low velocity bodies under several geothermal areas and high velocity anomalies associated with the subducting plate

kinematics of active deformation in the sulaiman lobe and range pakistan the western margin of the indian plate is highly oblique to the direction of convergence between india and asia and represents an excellent example of large scale oblique continent continent collision determining the strain field in western pakistan and how it relates to the plate motion and plate margin geometry affords an exceptional opportunity for understanding oblique margin processes in general through the inversion of regional and teleseismic body waves we have determined the source parameters of 10 moderate sized earthquakes that occurred between 1964 and 1985 in and around the sulaiman range pakistan the earthquakes are dominantly thrust events with slip vectors that are approximately perpendicular to the lobate sulaiman mountain front slip vector orientations rotate 60 70 from a n s to a wnw ese direction of compression consistent with the geometries of the complex festoon shaped mountain belts of this margin we have estimated the spatial variation of the horizontal strain rate and velocity fields within sulaiman using vertically averaged models that accommodate plate motion constraints within a deforming layer the most important factors determining the style of strain rotation in the sulaiman lobe and range are the presence of pure strike slip motion along the chaman fault and the relatively rigid and undeformed katawaz basin that is therefore allowed to translate obliquely relative to india this same conclusion is obtained using either a three dimensional frictional analogue model with significant basal tractions or a thin sheet viscous numerical model without basal tractions thrusting in a predominantly nw se direction in the sulaiman range accommodates 5 14 mm yr of n s motion between india eurasia and 3 6 mm yr of e w shortening seismic moment release this century within the india eurasia plate boundary zone west of the western himalayan syntaxis constitutes roughly 40 of the expected total seismic moment release for this time period particularly significant moment rate deficits exist within the sulaiman range and along the chaman fault

the thermal responses of rock art pigments implications for rock art weathering in southern africa the san rock art of southern africa is an international heritage subject to degradation and loss resulting from weathering the paintings occur within rock shelters where many are exposed to direct solar radiation for varying periods rather than occurring in dark caves as part of a study on the factors thought to be impacting weathering data were collected pertaining to rock and pigment temperatures as well as humidity within the rock shelters in addition xrd analyses were undertaken on pigment samples and the pigment to rock and pigment to pigment contacts were investigated by means of sem pigments were found to be composed of ferric oxide the ochre and a gypsum clay mix the white and to occur as a layer on top of rather than penetrating into the sandstone noncontact infrared sensors were used to monitor the temperatures of the actual pigments while micro thermocouples to monitor the surrounding nonpainted rock surfaces thermal data show that there are significant differences between the white and the ochre pigments both in terms of actual temperatures and short term thermal responses noticeably the white paint exhibits relatively large thermal fluctuations as compared to the ochre or the rock over the 20 s to 1 min timescale these thermal variations may induce pigment to pigment stresses within the painting the pigmented areas also exhibit different temperatures to the surrounding paint free rock suggesting that there may be both within painting and between painting and rock including the rock beneath the painting stresses that can lead to degradation humidity data were found to be inadequate for any meaningful evaluation of the moisture conditions

mode of strong earthquake recurrence in the central ionian islands greece possible triggering due to coulomb stress changes generated by the occurrence of previous strong shocks the spatiotemporal distribution of shallow strong m 6 3 earthquakes occurring in the area of central ionian islands is analyzed these shocks are generated on two adjacent fault segments with different strike but both segments are associated with strike slip faulting constituting the boundary between continental collision to the north and oceanic subduction to the south seismic activity is concentrated in short time intervals alternating with much longer relatively quiescent periods each active period consists of a relatively large event or series two to four of events occurring closely both in space and time this alteration was observed to happen four times since 1867 the period when complete data exist for the study area since the phenomenon is not strictly periodic and during each active period multiple events occurred i attempted to interpret the seismic behavior on the basis of possible trig gering i then investigated how changes in coulomb failure function dcff asso ciated with one or more earthquakes may trigger subsequent events both the co seismic slip due to the generation of the strong earthquakes and stress buildup associated with the two major fault segments were taken into account for the dcff calculation earthquakes can be modeled as static dislocations in elastic half space and the stress pattern has been calculated according to the geometry and slip of each of the faults that ruptured in the chain of events these calculations show that 13 out of 14 earthquakes of m 6 3 were preceded by a static stress change that encouraged failure the magnitude of the stress increases transferred from one earthquake to another ranged from 0 01 mpa 0 1 bar to over 0 1 mpa 1 bar showing that stress transfer adequately explains the occurrence pattern of these events maps of current dcff provide additional information to long term earthquake prediction areas of positive dcff have been identified at two sites in kefalonia and lefkada faults respectively where the next strong events are expected to occur a fact that will substantiate the hypothesis elaborated in this article

tectonic implications and seismicity triggering during the 2008 baluchistan pakistan earthquake sequence abstract a damaging and widely felt moderate earthquake mw 6 4 hit the rural mountainous region of southwestern pakistan on october 28 2008 the main shock was followed by another earthquake of identical magnitude mw 6 4 on the next day the spatial distribution of aftershocks and focal mechanism revealed a nw se striking rupture with right lateral strike slip motion which is sympathetic to the nnw sse striking active mapped urghargai fault the occurrence of strike slip earthquakes suggests that along with the thrust faults strike slip faults too are present beneath the fold and thrust belt of sulaiman kirthar ranges and accommodates some of the relative motion of the indian and eurasian plates to assess the characteristics of this sequence the statistical parameters like aftershocks temporal decay b value of g r relationship partitioning of radiated seismic energy due to aftershocks and spatial fractal dimension d value have been examined the b value is estimated as 1 03 0 42 and suggests the tectonic genesis of the sequence and crustal heterogeneity within rock mass the low p value of 0 89 0 07 implies slow decay of aftershocks activity which is probably an evidence for low surface heat flow a value of spatial fractal dimension of 2 08 0 02 indicates random spatial distribution and that the source is a two dimensional plane filled up by fractures the static coseismic coulomb stress changes due to the foreshock mw 5 3 were found to increase stress by more than 0 04 bars at the hypocenter of the main shock thus promoting the failure the cumulative coseismic coulomb stress changes due to the foreshock and mainshocks suggest that most of the aftershocks occurred in the region of increased coulomb stress and to the se to the mainshock rupture

radio echo sounding of svalbard glaciers peculi arities of radio echo sound ing of mountain gl aciers and ice fields between nunataks from terrestria l vehicles and from heli copters are consi dered in this paper the possibility of using compar atively high frequen cies of up to 865 mhz for sounding suc h glaciers is demonst rated on the basis of expe rimental data results of airbo rne radio echo so unding of svalba rd gl aciers of various types dimensions and regime obtained with the help of the 620 m hz airbo rne equipment of high resolution are shown returns from the gla cier bed have been obtained on the majority of glaciers unde r in vestigation the firn regions of ice fields with temp erate regimes flowing between nuna taks are mostly an exception depre ssion in the glacier bed with the ice thic kne ss up to 540 m as well as int ernal reflecting boundaries have been detected in some glaciers ic e volum es of glaciers have been determined from the airborne radio echo sounding data with the use of a parabolic appr oximation to the cross section glacier profiles good correl ational dependence between ice volume and surface area of glaciers has been established and is use d to estimate the ic e and water resources in sva lbard glaciers

evolution of the stress field in the northern aegean sea greece summary the evolution of the stress field in the area of the northern aegean sea during the 20th century has been studied the area is dominated by dextral strike slip faulting and is characterized by frequent strong earthquakes coulomb stress changes dcff were calculated assuming that earthquakes can be modelled as static dislocations in an elastic half space and taking into account both the coseismic slip in large mi7 0 earthquakes and the slow tectonic stress build up along the major fault segments the stress change calculations were performed for strike slip faults of strike dip and rake appropriate to the large events we evaluate whether these stress changes brought a given large earthquake closer to or farther from failure it was found that each of the large events occurred in regions of increased calculated coulomb stress moreover the majority of smaller events for which reliable fault plane solutions are available were also located in areas of positive dcff by extending the calculations to 2020 and assuming that no additional large mi7 0 earthquake occurs between 1999 and 2020 possible sites of future large earthquakes are identified

bath s law derived from the gutenberg richter law and from aftershock properties 1 the empirical bath s law states that the average difference in magnitude between a mainshock and its largest aftershock is 1 2 regardless of the mainshock magnitude following vere jones 1969 and console et al 2003 we show that the origin of bath s law is to be found in the selection procedure used to define mainshocks and aftershocks rather than in any difference in the mechanisms controlling the magnitude of the mainshock and of the aftershocks we use the etas model of seismicity which provides a more realistic model of aftershocks based on i a universal gutenberg richter gr law for all earthquakes and on ii the increase of the number of aftershocks with the mainshock magnitude using numerical simulations of the etas model we show that this model is in good agreement with bath s law in a certain range of the model parameters

static stress transfer and earthquake triggering no lower threshold in sight the main objective of this study is to see if a lower threshold for earthquake triggering exists resolving this issue is important for the understanding of earthquake mechanics and for the purpose of hazard analysis we compute the cumulative static stress changes imposed on 63 m 4 5 earthquakes in central california between 1969 and 1998 by adding the stress changes imposed by all previous m 4 5 earthquakes as a function of time prior to the events we find that 85 of the cumulative stress changes at the time of rupture are positive for stress change magnitudes of 10 kpa 0 1 bar and 70 are positive for stress changes of 10 kpa 0 1 bar as well as 1 kpa 0 01 bar a comparison between these results and those obtained for synthetic catalogs in which the timing or focal mechanisms of the earthquakes were randomized shows that this degree of triggering is very unlikely to be found in a random catalog thus we conclude that no lower threshold for earthquake triggering in central california has been found we show that the temporal distribution of stress changes that discourage failure is consistent with the theoretical prediction that the time delay increases with the magnitude of the stress change

volume area scaling parameterisation of norwegian ice caps a comparison of different approaches over the recent decades glaciers have in general continued to lose mass causing surface lowering volume reduction and frontal retreat thus contributing to global sea level rise when making assessments of present and future sea level change and management of water resources in glaciated catchments precise estimates of glacier volume are important the glacier volume cannot be measured on every single glacier therefore the global glacier volume must be estimated from models or scaling approaches volume area scaling is mostly applied for estimating volumes of glaciers and ice caps on a regional and global scale by using a statistical theoretical relationship between glacier volume v and area a v ca for explanation of the parameters c and see eq 1 in this paper a two dimensional 2d glacier model has been applied on four norwegian ice caps hardangerjokulen nordre folgefonna sporteggbreen and vestre svartisen in order to obtain values for the volume area relationship on ice caps

new empirical relationships among magnitude rupture length rupture width rupture area and surface displacement source parameters for historical earthquakes worldwide are compiled to develop a series of empirical relationships among moment magnitude m surface rupture length subsurface rupture length downdip rupture width rupture area and maximum and average displacement per event the resulting data base is a significant update of previous compilations and includes the additional source parameters of seismic moment moment magnitude subsurface rupture length downdip rupture width and average surface displacement each source parameter is classified as reliable or unreliable based on our evaluation of the accuracy of individual values only the reliable source parameters are used in the final analyses in comparing source parameters we note the following trends 1 generally the length of rupture at the surface is equal to 75 of the subsurface rupture length however the ratio of surface rupture length to subsurface rupture length increases with magnitude 2 the average surface displacement per event is about one half the maximum surface displacement per event and 3 the average subsurface displacement on the fault plane is less than the maximum surface displacement but more than the average surface displacement thus for most earthquakes in this data base slip on the fault plane at seismogenic depths is manifested by similar displacements at the surface log linear regressions between earthquake magnitude and surface rupture length subsurface rupture length and rupture area are especially well correlated showing standard deviations of 0 25 to 0 35 magnitude units most relationships are not statistically different at a 95 significance level as a function of the style of faulting thus we consider the regressions for all slip types to be appropriate for most applications regressions between magnitude and displacement magnitude and rupture width and between displacement and rupture length are less well correlated and have larger standard deviation than regressions between magnitude and length or area the large number of data points in most of these regressions and their statistical stability suggest that they are unlikely to change significantly in response to additional data separating the data according to extensional and compressional tectonic environments neither provides statistically different results nor improves the statistical significance of the regressions regressions for cases in which earthquake magnitude is either the independent or the dependent parameter can be used to estimate maximum earthquake magnitudes both for surface faults and for subsurface seismic sources such as blind faults and to estimate the expected surface displacement along a fault for a given size earthquake

global distributions of glacier properties a stochastic scaling paradigm many problems in global climate and earth systems science require knowledge of regional or global scale distributions of glacier properties which includes mass balance ice velocity flux thickness volume and surface area among others with roughly 160 000 glaciers worldwide obtaining information on the global probability distributions of most ice properties is expensive and often infeasible only surface area distributions are relatively easy to measure either by direct observation or remote sensing while other properties are difficult to observe this work shows that scaling relationships from the continuum dynamics of ice can link the distribution of surface areas to the global and regional distributions of any other continuum property some data inventories already exist for constructing reasonable distributions of glacier sizes and this analysis presents theoretical arguments based on glacier network topologies similar in concept to river networks to suggest a power law times an exponential distribution of surface areas in agreement with the data therefore by using existing data or the theoretical distributions of surface areas specific distributions for other glacier properties in any region of the world can be constructed as an example predictions up to a scaling constant are made for the distribution of glacier volumes characteristic thicknesses characteristic velocities and characteristic response times in the alps

spatio temporal fluctuations over chorabari glacier garhwal himalaya india between 1976 and 2017 abstract the current research work deals with the health of chorabari glacier between 1976 and 2017 using multi spectral and multi dated satellite data series of landsat mss tm and etm and resourcesat ii liss iv result closely reveals that the studied glacier receding continuously with inconsistent rate for the last 41 years and rate of receding dominates significantly after 2012 it lost 306 43 61 m total length 7 46 1 48 m a 1 0 074 km2 frontal area 0 0018 km2 a 1 0 31 km2 24 glaciated area 0 007 km2 a 1 0 015 km3 32 60 glaciated volume the upward migration of sla snow line altitude from 5265 m to 5290 m also suggests that the melting process were prevailing during the study tenure an existence of supra glacial lakes and its successive growth over the surface of chorabari glacier further justifies that the temperature of the surroundings has increased significantly and influences the melting process as well the melting process between 1976 and 1990 of the studied glacier directly influenced by the frequent episodes of precipitation and temperature anomalies of central himalayan region during 1960 1990 while the melting process after 1990 is directly influenced by the increase in average mean temperature and decrease in average mean precipitation of garhwal himalayan region the tree ring data of garhwal himalaya region also well matches the precipitation data of imd indian meteorological department the overall analysis explains that the chorabari glacier is retreating continuously since 1976

secondary aftershocks and their importance for aftershock forecasting the potential locations of aftershocks which can be large and damaging are often forecast by calculating where the mainshock increased stress we find however that the mainshock induced stress field is often rapidly altered by aftershock induced stresses we find that the percentage of aftershocks that are secondary aftershocks or aftershocks triggered by previous aftershocks increases with time after the mainshock if we only consider aftershock sequences in which all aftershocks are smaller than the mainshock the percentage of aftershocks that are secondary also increases with mainshock magnitude using the california earthquake catalog and monte carlo trials we estimate that on average more than 50 of aftershocks produced 8 or more days after m 5 mainshocks and more than 50 of all aftershocks produced by m 7 mainshocks that have aftershock sequences lasting at least 15 days are triggered by previous aftershocks these results suggest that previous aftershock times and locations may be important predictors for new aftershocks we find that for four large aftershock sequences in california an updated forecast method using previous aftershock data and neglecting mainshock induced stress changes can outperform forecasts made by calculating the static coulomb stress change induced solely by the mainshock manuscript received 20 november 2002

weathering of sandstone by the combined action of frost and salt preliminary results from a continuing series of laboratory experiments designed to examine the combined effects of salt and frost weathering indicate that some salts greatly enhance the breakdown of rocks by frost samples of ardingly sandstone from southeast england were soaked in saturated solutions of sodium chloride or sodium sulphate and subjected to alternating cycles of freezing and thawing rapid disintegration of the sandstone occurred within twenty cycles in each of the salt solutions in contrast samples subjected to freezing and thawing in deionized water suffered very little damage unless they were saturated under vacuum when samples were subjected to twenty cycles of wetting and drying at temperatures above 0 c those soaked in deionised water or sodium chloride suffered no appreciable damage but those soaked in sodium sulphate rapidly disintegrated tentative explanations of these results are offered the enhancement of frost weathering by salt appears to have been overlooked by many writers yet it is likely to be an important geomorphological process in those areas of mid and high latitudes where rocks are saturated with sodium salts

the 2001 skyros northern aegean greece earthquake sequence off fault aftershocks tectonic implications and seismicity triggering was identified as a possible site for the occurrence of a strong event by papadimitriou and sykes 2001 who applied an evolutionary stress model in the northern aegean area 4 the paper analyzes the details of the earthquakes in the skyros sequence aiming to contribute to the understanding of the seismotectonic properties in this area where the western termination of the north aegean strike slip faulting against the mainland of greece takes place the co seismic stress changes associated with the main shock are computed and the areas of static stress increases are correlated with the aftershock spatial distribution

properties of aftershock sequences in southern california the temporal behavior of 39 aftershock sequences in southern california 1933 1988 was modeled by the modified omori relation minimum magnitudes for completeness of each sequence catalog were determined and the maximum likelihood estimates of the parameters k p and c with the standard errors on each were determined by the ogata algorithm the b value of each sequence was also calculated many of the active faults in the region both strike slip and thrust were sampled the p values were graded in terms of the size of the standard error relative to the p value itself most of the sequences were modeled well by the omori relation many of the sequences had p values close to the mean of the whole data set 1 11 0 25 but values significantly different from the mean as low as 0 7 and as high as 1 8 exist no correlation of p with either the b value of the sequence or the mainshock magnitude was found the results suggest a direct correlation of p values is with surface heat flow with high values in the salton trough high heat flow and one low value in the san bernardino mountains and on the edge of the ventura basin both low heat flow the large fraction of the sequences with p values near the mean are at locations where the heat flow is near the regional mean 74 mw m2 if the hypothesis that aftershock decay rate is controlled by temperature at depth is valid the effects of other factors such as heterogeneity of the fault zone properties are superimposed on the background rate determined by temperature surface heat flow is taken as an indicator of crustal temperature at hypocentral depths but the effects on heat flow of convective heat transport and variations in near surface thermal conductivity invalidate any simple association of local variations in heat flow with details of the subsurface temperature distribution the interpretation is that higher temperatures in the aftershock source volume caused shortened stress relaxation times in the fault zone materials leading to a faster decay rate higher p value in 1967 mogi proposed such a relation on the basis of japanese data seismic velocity distributions published for southern california generally support the hypothesis with low velocities higher temperatures corresponding to high p values and vice versa

modeling glacier thickness distribution and bed topography over entire mountain ranges with glabtop application of a fast and robust approach 1 the combination of glacier outlines with digital elevation models dems opens new dimensions for research on climate change impacts over entire mountain chains of particular interest is the modeling of glacier thickness distribution where several new approaches were proposed recently the tool applied herein glabtop glacier bed topography is a fast and robust approach to model thickness distribution and bed topography for large glacier samples using a geographic information system gis the method is based on an empirical relation between average basal shear stress and elevation range of individual glaciers calibrated with geometric information from paleoglaciers and validated with radio echo soundings on contemporary glaciers it represents an alternative and independent test possibility for approaches based on mass conservation and flow as an example for using glabtop in entire mountain ranges we here present the modeled ice thickness distribution and bed topography for all swiss glaciers along with a geomorphometric analysis of glacier characteristics and the overdeepenings found in the modeled glacier bed these overdeepenings can be seen as potential sites for future lake formation and are thus highly relevant in connection with hydropower production and natural hazards the thickest ice of the largest glaciers rests on weakly inclined bedrock at comparably low elevations resulting in a limited potential for a terminus retreat to higher elevations the calculated total glacier volume for all swiss glaciers is 75 22 km3 for 1973 and 65 20 km3 in 1999 considering an uncertainty range of 30 these results are in good agreement with estimates from other approaches

thermal stress weathering and the spalling of antarctic rocks using in situ field measurements laboratory analyses and numerical modeling we test the potential efficacy of thermal stress weathering in the flaking of millimeter thick alteration rinds observed on cobbles and boulders of ferrar dolerite on mullins glacier mcmurdo dry valleys mdv in particular we examine whether low magnitude stresses arising from temperature variations over time result in thermal fatigue weathering yielding slow crack propagation along existing cracks and ultimate flake detachment our field results show that during summer months clasts of ferrar dolerite experience large temperature gradients across partially detached alteration rinds 4 7 c mm 1 and abrupt fluctuations in surface temperature up to 12 c min 1 the latter are likely due to the combined effects of changing solar irradiation and cooling from episodic winds the results of our thermal stress model coupled with subcritical crack growth theory suggest that thermal stresses induced at the base of thin alteration rinds 2 mm thick common on rocks exposed for 105 years may be sufficient to cause existing cracks to propagate under present day meteorological forcing eventually leading to rind detachment the increase in porosity observed within alteration rinds relative to unaltered rock interiors as well as predicted decreases in rind strength based on allied weathering studies likely facilitates thermal stress crack propagation through a reduction of fracture toughness we conclude that thermal stress weathering may be an active though undervalued weathering process in hyperarid terrestrial polar deserts such as the stable upland region of the mdv

afghanistan structure greater india concept and eastern tethys evolution abstract the large and complex area between central asia and the arabia india block includes from north to south the tien shan and hindu kush kun lun hercynian belts the turkman farah rud and tanghla shan neokimmerian belt the zagros makran baluch himalayan alpine belt and relics of corresponding oceanic spaces the angarian or gondwanian affinities of the different blocks separated by these successive peri indian belts are discussed an interpretation is proposed for the paleogeographic and structural evolution of this area from early paleozoic to present this interpretation is based on geologic and paleomagnetic data and on global tectonic considerations the hindu kush kun lun pre hercynian ocean probably separated laurasia from gondwanaland it was an early paleozoic tethys tethys 1 the tien shan ocean may have been a marginal basin for the hindu kush kun lun ocean the turkman farah rud tanghla shan pre neokimmerian ocean resulted from the break up of the gondwanaland margin its opening seems to have been related to the pre hercynian ocean closure resulting in the formation of a new tethys tethys 2 its subsequent closure may also have been related to the opening of the zagros baluch indus tsang po pre alpine ocean tethys 3 according to this interpretation eurasia appears to have increased from early paleozoic to cenozoic by successive accretion of cratonic blocks which came from the south through the tethys this evolution can be compared to the similar mediterranean evolution this interpretation is in agreement with the greater india concept however the northern border of greater india differs according to the stage of the gondwanaland evolution which is considered actually greatest india extended north to the caledonian belt and consequently has recorded the whole history of the eastern tethys

laboratory simulation of rock weathering by salt crystallization and hydration processes in hot arid environments the results of a series of experiments are reported in this paper which were designed to differentiate between the forces of crystal growth and hydration in salt weathering using a single salt hydrate system sodium sulphate five contrasting rock types and several diurnal temperature relative humidity cycles which permitted or inhibited these processes and simulated ground surface climates in hot arid environments it was shown that hydration of sodium sulphate is an effective mechanism of rock disintegration but that it is significantly less destructive than crystal growth pressure crystallization of thenardite na2so4 is in turn more effective in rock weathering than the crystal growth of mirabilite na2so4 10h2o in general rates of disintegration were most rapid where the diurnal temperature range was extreme and relative humidity lowest

fractal dimension and b value on creeping and locked patches of the san andreas fault near parkfield california we tested the hypotheses 1 that the fractal dimension d of hypocenters are different in a locked and a creeping segment of the san andreas fault and 2 that the relationship d 2b holds approximately where b is the slope of the frequency magnitude relationship the test area was the 30 to 50 km fault segment north of park eld for which two earthquake catalogs exist the borehole high resolution seismic network data and the u s geological survey data which have a minimum magnitude of completeness of mc 0 4 and mc 1 0 1 2 respectively the relative location errors in the two catalogs are estimated as 0 25 km and less than 1 km respectively the periods of high quality data available extend from 1987 to 1998 5 and 1981 to 2000 2 respectively furnishing 2609 and 3775 events for analysis in the two catalogs in the locked part 0 5 b 0 7 and 0 96 d 1 14 whereas in the creeping segment 1 1 b 1 6 and 1 45 d 1 72 however the spatial distribution of the hypocenters in the creeping segment is not well approximated by a fractal distribution we conclude 1 that the frequency magnitude distribution as described by b as well as the fractal dimension d are different in the locked and creeping segments near park eld 2 that the spatial distribution in the creeping segment is not well approximated by a fractal distribution and 3 that the relationship d 2b holds in the locked segment where both parameters can be measured accurately thus we propose that the heterogeneity of seismogenic volumes lead to differences in d and b and that these differences where established by high quality data may furnish clues concerning properties of fault zones

the 2007 talala saurashtra western india earthquake sequence tectonic implications and seismicity triggering abstract a damaging and widely felt moderate mw 5 0 earthquake occurred in the talala region of saurashtra gujarat western india on november 6 2007 the highly productive sequence comprised about 1300 micro earthquakes m 0 5 out of which 325 of m 1 5 that occurred during november 6 2007 january 10 2008 were precisely located the spatial aftershock distribution revealed a ne sw striking fault in accordance with the centroid moment tensor solution which in turn implies left lateral motion the orientation and sense of shear are consistent with similarly orientated geological fault identified in the area from satellite imagery and field investigation the aftershocks temporal decay b value of frequency magnitude distribution spatial fractal dimension d and slip ratio ratio of the slip occurred on the primary fault to the total slip were examined with the purpose to identify the properties of the sequence the high b value 1 18 0 01 may be attributed to the paucity of the larger m 4 0 aftershocks and reveals crustal heterogeneity and low stress regime the high p value 1 10 0 39 implying fast decay rate of aftershocks evidences high surface heat flux a value of the spatial fractal dimension d equal to 2 21 0 02 indicates random spatial distribution and source in a two dimensional plane that is being filled up by fractures a slip ratio of 0 42 reveals that more slip occurred on secondary fault systems the static coulomb stress changes due to the coseismic slip of the main shock enhanced off fault aftershock occurrence the occurrence of a moderate earthquake mw 4 3 on october 5 2008 inside a region of positive coulomb stress changes supports the postulation on aftershock triggering when the stress changes were resolved on a cross section including the stronger m4 8 foreshock plane that is positioned adjacent to the main fault it became evident that the activity continued there due to stress transfer from the main rupture

regional and global volumes of glaciers derived from statistical upscaling of glacier inventory data 1 very few global scale ice volume estimates are available for mountain glaciers and ice caps although such estimates are crucial for any attempts to project their contribution to sea level rise in the future we present a statistical method for deriving regional and global ice volumes from regional glacier area distributions and volume area scaling using glacier area data from 123 000 glaciers from a recently extended world glacier inventory we compute glacier volumes and their sea level equivalent sle for 19 glacierized regions containing all mountain glaciers and ice caps on earth on the basis of total glacierized area of 741 103 68 103 km2 we estimate a total ice volume of 241 103 29 103 km3 corresponding to 0 60 0 07 m sle of which 32 is due to glaciers in greenland and antarctica apart from the ice sheets however our estimate is sensitive to assumptions on volume area scaling coefficients and glacier area distributions in the regions that are poorly inventoried i e antarctica north america greenland and patagonia this emphasizes the need for more volume observations especially of large glaciers and a more complete world glacier inventory in order to reduce uncertainties and to arrive at firmer volume estimates for all mountain glaciers and ice caps

estimate of the total volume of svalbard glaciers and their potential contribution to sea level rise using new regionally based scaling relationships we present a set of new volume scaling relationships specific to svalbard glaciers derived from a sample of 60 volume area pairs glacier volumes are computed from ground penetrating radar gpr retrieved ice thickness measurements which have been compiled from different sources for this study the most precise scaling models in terms of lowest cross validation errors are obtained using a multivariate approach where in addition to glacier area glacier length and elevation range are also used as predictors using this multivariate scaling approach together with the randolph glacier inventory v3 2 for svalbard and jan mayen we obtain a regional volume estimate of 6700 835 km3 or 17 2 mm of sea level equivalent sle this result lies in the mid to low range of recently published estimates which show values as varied as 13 and 24 mm sle we assess the sensitivity of the scaling exponents to glacier characteristics such as size aspect ratio and average slope and find that the volume of steep slope and cirque type glaciers is not very sensitive to changes in glacier area

the 1997 kagoshima japan earthquake doublet a quantitative analysis of aftershock rate changes we quantitatively map relative rate changes for the aftershock sequence following the second mainshock of the 1997 earthquake doublet m w 6 1 m w 6 0 in the kagoshima province japan using the spatial distribution of the modified omori law parameters for aftershocks that occurred during the 47 8 days between the two mainshocks we forecast the aftershock activity in the next 50 days and compare it to the actually observed rates the relative rate change map reveals four regions with statistically significant relative rate changes three negative and one positive our analysis suggests that the coseismic rate changes for off fault aftershocks could be explained by changes in static stress however to explain the activation and deactivation of on fault seismicity other mechanism such as unusual crustal properties and the presence of abundant crustal fluids are required

frost and salt weathering further experimental results a laboratory experiment has been conducted to examine the effects of frost and salt weathering i e physical breakdown by the freezing of salt solutions on a limestone results show that the presence of certain salts in solution can inhibit frost damage these findings are in direct conflict with those presented by goudie 1974 and more recently williams and robinson 1981 comparison of the experimental methods used in each of these three studies suggests that opposing results can be explained in terms of the different experimental procedures which were employed if salt supply is frequent and plentiful then it seems likely that rock breakdown will be enhanced this is the case represented by the experiment of williams and robinson conversely if the salt supply is limited and the amounts of salt remain more or less constant then rock breakdown will be inhibited the case of the present experimental study caution is therefore advocated when attempting to extrapolate laboratory derived results to infer on the behaviour of rocks under natural conditions several environmental situations in which frost and salt weathering may be a possibility are dsiscussed but it is concluded that further field data especially concerning temperature regimes and salt availability at and below rock surfaces in cold regions would be necessary before more definite statements could be made about the efficacy of this process

spatial variability of seismicity parameters in aftershock zones the spatial variability of the b value of the frequency magnitude relationship and the decay rate of aftershocks as described by the p value of the modified omori law is investigated by using dense spatial grids we map out the distribution of b and p values within the landers northridge morgan hill and kobe aftershock sequences considerable spatial variability is found with b values of independent subvolumes ranging from 0 6 to 1 4 and p values ranging from 0 6 to 1 8 these systematic and statistically highly significant differences argue that it is an oversimplification to assign one single p and b value to an aftershock sequence that extends up to 100 km the spatial distribution of these two parameters is compared with the slip distribution during the mainshock suggesting that the areas of largest slip release correlate with high b value regions we hypothesize that the frictional heat created during the event may influence the p value distribution within an aftershock zone while applied shear stress crack density and pore pressure govern the frequency magnitude distribution by investigating the frequency magnitude distribution separately for preseismic and postseismic periods for the morgan hill mainshock we find that only the volume in the vicinity of the highest slip release shows a significant increase in the b value which decays to premainshock values within a year surrounding areas of the aftershock zone show an approximately constant b value with time because the aftershock hazard after a mainshock depends strongly on both the b and p value we propose that aftershock hazard assessment can be improved by taking into account the spatial distribution of the parameters

sandstone weathering processes damaging prehistoric rock paintings at the albarracin cultural park ne spain the rock paintings in cliff foot caves of the albarracin cultural park are known as some of the most important evidences of the levantine prehistoric art of spain 8000 3000 bp the paintings are on sandstone buntsandstein facies of triasic age which may develop intense weathering the analysis of the variables controlling the weathering indicate that salt and wetting drying weathering are responsible for granular disintegration and flaking which lead to rock painting deterioration

weathering geomorphology texts 2 cliff ollier 1984 longman group ltd essex england 2d ed 270 pp stg 11 50 paperback

the physical basis of glacier volume area scaling ice volumes are known for only a few of the roughly 160 000 glaciers worldwide but are important components of many climate and sea level studies which require water flux estimates a scaling analysis of the mass and momentum conservation equations shows that glacier volumes can be related by a power law to more easily observed glacier surface areas the relationship requires four closure choices for the scaling behavior of glacier widths slopes side drag and mass balance reasonable closures predict a volume area scaling exponent which is consistent with observations giving a physical and practical basis for estimating ice volumes glacier volume is insensitive to perturbations in the mass balance scaling but changes in average accumulation area ratios reflect significant changes in the scaling of both mass balance and ice volume

sporteggbreen western norway in the past present and future simulations with a two dimensional dynamical glacier model a two dimensional shallow ice flow model yielding the glacier geometry at selected time intervals is used to simulate the development of sporteggbreen 1 from 8000 cal yr bp to the present 2 from ad 2011 to 2050 and 3 extending forward in time to ad 2100 and 2200 glacier surface geometry subglacial topography mass balance data internal deformation and subglacial sliding are used as input data for the model runs to force the model from 8000 cal yr bp to the present a mass balance series based on the equilibrium line altitude ela variations on jostedalsbreen to the west of sporteggbreen is applied a 50 reduction of the ela amplitude at jostedalsbreen is used to construct a new mass balance series and it was found that this gives a reasonably good coherence between the modelled and the real glacier the modelled time series for ela and length changes indicate that the glacier melted away c 7300 cal yr bp and was absent for c 1700 years it reformed c 5400 cal yr bp because of a mo

in the shadow of 1857 the effect of the great ft tejon earthquake on subsequent earthquakes in southern california the great 1857 fort tejon earthquake is the largest earthquake to have hit southern california during the historic period we investigated if seismicity patterns following 1857 could be due to static stress changes generated by the 1857 earthquake when post 1857 earthquakes with unknown focal mechanisms were assigned strike slip mechanisms with strike and rake determined by the nearest active fault 13 of the 13 southern california m 5 5 earthquakes between 1857 and 1907 were encouraged by the 1857 rupture when post 1857 earthquakes in the transverse ranges with unknown focal mechanisms were assigned reverse mechanisms and all other events were assumed strike slip 11 of the 13 earthquakes were encouraged by the 1857 earthquake these results show significant correlations between static stress changes and seismicity patterns the correlation disappears around 1907 suggesting that tectonic loading began to overwhelm the effect of the 1857 earthquake early in the 20th century

properties of the 2003 lefkada ionian islands greece earthquake seismic sequence and seismicity triggering on 14 august 2003 lefkada island central ionian was strongly af fected by an mw 6 2 earthquake a dense temporary seismic network was installed one day after and accurately located hundreds of aftershocks that defined in detail the main rupture as well as the activity distribution in the neighboring fault segments the main rupture occupied the northwestern part of the coastline and trends north northeast south southwest in agreement with regional tectonics regional network locations were appropriately calibrated using the local network data allowing the relocation of the mainshock and strong m 4 5 or larger aftershocks during the first day intense aftershock activity took place up to 40 km beyond the southern end of the main rupture theoretical static stress changes from the mainshock give a preliminary explanation for the aftershock distribution aside from the main rupture as well as triggering of seismicity in the nearby kefalonia fault providing evidence for future seismic hazard ensuing from this fault

earthquakes and associated deformation in northern baluchistan 1892 2001 we examine a century of seismicity and earthquake related deformation on the western margin of the indian plate in the pakistan region of northern baluchistan several catalogs of earthquakes for this region currently exist but early catalogs in particular suffer from errors incompleteness inhomogeneity and location bias we form a new catalog of more than 1000 earthquakes using original sources to confirm macroseismic locations and assign m s magnitudes to earthquakes since 1892 in doing so we reveal a systematic east northeast bias in locations caused largely by the uneven global distribution of seismic stations used in their determination an appendix provides narrative accounts and historical references to 34 significant earthquakes in the region the pattern of seismicity in the past century shows activity over a 700 km long 200 km wide segment of the plate boundary with predominantly strike slip faulting to the west and thrust faulting to the east at its narrowest near 29 n transpression of the plate boundary is partitioned into reverse and strike slip components separated by approximately 100 km the m 7 3 1931 mach earthquake slip 1 1 m on a 40 east southeast dipping reverse fault released fault normal stresses that may have unclamped the subsequent m 7 7 left lateral quetta earthquake 4 years later the northern chaman fault system in the past century has been largely inactive suggesting that this time period is not representative of long term activity in the region and that up to 4 m of potential slip is currently available to drive one or more future m 7 earthquakes despite triangulation installed in the late nineteenth and early twentieth centuries no recent geodetic data are available to permit plate boundary velocities to be measured directly

ice thickness measurements and volume estimates for glaciers in norway glacier volume and ice thickness distribution are important variables for water resource management in norway and the assessment of future glacier changes we present a detailed assessment of thickness distribution and total glacier volume for mainland norway based on data and modelling glacier outlines from a landsat derived inventory from 1999 to 2006 covering an area of 2692 81 km 2 were used as input we compiled a rich set of ice thickness observations collected over the past 30 years altogether interpolated ice thickness measurements were available for 870 km 2 32 of the current glacier area of norway with a total ice volume of 134 23 km 3 results indicate that mean ice thickness is similar for all larger ice caps and weakly correlates with their total area ice thickness data were used to calibrate a physically based distributed model for estimating the ice thickness of unmeasured glaciers the results were also used to calibrate volume area scaling relations the calibrated total volume estimates for all norwegian glaciers ranged from 257 to 300 km 3

the potential for sea level rise new estimates from glacier and ice cap area and volume distributions projections of sea level rise from mountain glaciers and ice caps for the next century and beyond should be based on an assessment of the ice available for melting projections to date are based on all regions except greenland and antarctica the latter are considered separately by the ipcc yet no sound estimates for the appropriate volume of ice and its potential for sea level rise are evident in the literature an ice cap data set is compiled allowing the separate treatment of glacier area coverage data glacier inventory data are comprehensive enough in some regions to allow the estimation of glacier size distributions the differences in the distributions are related to a metric of the regional topographic variability allowing glacier size distributions to be estimated on a 1 latitude longitude grid of cells containing glaciers appropriate volume area scaling for glaciers and for ice caps gives global estimates of glacier and ice cap volumes by size class this leads to an estimate of the total ice volume of 0 087 0 010 106 km3 and a sea level rise equivalent of 0 241 0 026 m the glaciers and ice caps contribute 41 and 59 to these estimates respectively these values are based on data sets compiled during several decades mainly in the second half of the 20th century we compare our results to published results that include the glaciers and icecaps at the margins of the greenland and antarctic ice sheets

distributed ice thickness and volume of all glaciers around the globe 1 a new physically based approach for calculating glacier ice thickness distribution and volume is presented and applied to all glaciers and ice caps worldwide combining glacier outlines of the globally complete randolph glacier inventory with terrain elevation models shuttle radar topography mission advanced spaceborne thermal emission and reflection radiometer we use a simple dynamic model to obtain spatially distributed thickness of individual glaciers by inverting their surface topography results are validated against a comprehensive set of thickness observations for 300 glaciers from most glacierized regions of the world for all mountain glaciers and ice caps outside of the antarctic and greenland ice sheets we find a total ice volume of 170 103 21 103 km3 or 0 43 0 06 m of potential sea level rise

mesozoic ophiolites sutures and arge scale tectonic movements in afghanistan abstract the tectonic history of afghanistan appears to be the result of successive accretion of fragments of gondwana to the active margin of laurasia since the end of the paleozoic the margin in afghanistan lies along the present herat and panjshir faults south of hindu kush swings around the central pamirs and can presumably be traced along the present western altyn tagh and kunlun faults in tibet north of this boundary paleozoic rocks have been deformed in the upper paleozoic whereas south of it there is no trace of the hercynian orogeny the first collision of gondwanian fragments with laurasia probably occurred in the early mesozoic along the hindu kush and kunlun to the south ophiolites along the panjao and pangong nu chiang sutures respectively in central afghanistan and central tibet testify for another suturing event in the upper jurassic or lower cretaceous the indus tsangpo suture between india and tibet corresponds in eastern afghanistan to two ophiolite subbelts near kabul and khost both ophiolite complexes have been emplaced between maestrichtian and lower eocene by choking of two northward dipping subduction zones after complete contact between the indian and asian continents was achieved presumably in the end of eocene the penetration of india into asia caused large scale intra continental shortening a large part of the shortening was accommodated by strike slip faulting along mesozoic and more ancient sutures central afghanistan in particular was extruded to the west along the herat suture by the protrusion of the pamir wedge it subsequently collided with the lut block

seismicity analysis through point process modeling a review the occurrence times of earthquakes can be considered to be a point process and suitable modeling of the conditional intensity function of a point process is useful for the investigation of various statistical features of seismic activity this manuscript summarizes likelihood based methods of analysis of point processes and reviews useful models for particular analyses of seismicity most of the analyses can be implemented by the computer programs published by the author and collaborators

the randolph glacier inventory a globally complete inventory of glaciers the randolph glacier inventory rgi is a globally complete collection of digital outlines of glaciers excluding the ice sheets developed to meet the needs of the fifth assessment of the intergovernmental panel on climate change for estimates of past and future mass balance the rgi was created with limited resources in a short period priority was given to completeness of coverage but a limited uniform set of attributes is attached to each of the 198 000 glaciers in its latest version 3 2 satellite imagery from 1999 2010 provided most of the outlines their total extent is estimated as 726 800 34 000 km 2 the uncertainty about 5 is derived from careful single glacier and basin scale uncertainty estimates and comparisons with inventories that were not sources for the rgi the main contributors to uncertainty are probably misinterpretation of seasonal snow cover and debris cover these errors appear not to be normally distributed and quantifying them reliably is an unsolved problem combined with digital elevation models the rgi glacier outlines yield hypsometries that can be com bined with atmospheric data or model outputs for analysis of the impacts of climatic change on glaciers the rgi has already proved its value in the generation of significantly improved aggregate estimates of glacier mass changes and total volume and thus actual and potential contributions to sea level rise

a method to estimate the ice volume and ice thickness distribution of alpine glaciers sound knowledge of the ice volume and ice thickness distribution of a glacier is essential for many glaciological applications however direct measurements of ice thickness are laborious not feasible everywhere and necessarily restricted to a small number of glaciers in this paper we present a method to estimate the ice thickness distribution and the total ice volume of alpine glaciers this method is based on glacier mass turnover and principles of ice flow mechanics the required input data are the glacier surface topography the glacier outline and a set of borders delineating different ice flow catchments three parameters describe the distribution of the apparent mass balance which is defined as the difference between the glacier surface mass balance and the rate of ice thickness change and two parameters define the ice flow dynamics the method was developed and validated on four alpine glaciers located in switzerland for which the bedrock topography is partially known from radio echo soundings the ice thickness along 82 cross profiles can be reproduced with an average deviation of about 25 between the calculated and the measured ice thickness the cross sectional areas differ by less than 20 on average this shows the potential of the method for estimating the ice thickness distribution of alpine glaciers without the use of direct measurements

glacier volume estimation as an ill posed inversion estimating a glacier s volume by inferring properties at depth e g bed topography or basal slip from properties observed at the surface e g area and slope creates a calculation instability that grows exponentially with the size of the glacier random errors from this inversion instability can overwhelm all other sources of error and can corrupt thickness and volume calculations unless problematic short spatial wavelengths are specifically excluded volume area scaling inherently filters these short wavelengths and automatically eliminates the instability while numerical inversions can also give stable solutions by filtering the correct wavelengths explicitly as is frequently done when regularizing a model each of the scaling and numerical techniques has applications to which it is better suited and there are trade offs in resolution and accuracy but when calculating volume neither the modeling nor the scaling approach offers a fundamental advantage over the other both are significantly limited by the inherently ill posed inversion and even though both provide stable volume solutions neither can give unique solutions

neural networks applied to estimating subglacial topography and glacier volume abstract to predict the rate and consequences of shrinkage of the earth s mountain glaciers and ice caps it is necessary to have improved regional scale models of mountain glaciation and better knowledge of the subglacial topography upon which these models must operate the problem of estimating glacier ice thickness is addressed by developing an artificial neural network ann approach that uses calculations performed on a digital elevation model dem and on a mask of the present day ice cover because suitable data from real glaciers are lacking the ann is trained by substituting the known topography of ice denuded regions adjacent to the ice covered regions of interest and this known topography is hidden by imagining it to be ice covered for this training it is assumed that the topography is flooded to various levels by horizontal lake like glaciers the validity of this assumption and the estimation skill of the trained ann is tested by predicting ice thickness for four 50 km 50 km regions that

sandstone weathering a century of research and innovation abstract a review of sandstone weathering research particularly in the past 100 years reveals a trajectory of enquiry from early description and classification of features to development of process based explanations to decreasing scales of investigation and a disparity between understanding of process es and explanations of the genesis of sandstone weathering features developments in expositions on mesoscale weathering features on sandstone surfaces are discussed demonstrating a range of approaches to weathering phenomena field based and laboratory based that must be linked to provide an explanation of observed features on a landform scale throughout the twentieth century a thematic chronology highlights certain trends in research description of forms often in arid and semi arid environments single process form models an emphasis on experimentation difficulties in measuring weathering rates and a persistent emphasis on physical causes of breakdown a new research agenda is promoted in which biodeterioration and chemical processes gain parity a holistic approach based on conceptual modeling of weathering systems gains prominence and scale issues are addressed more rigorously

tidal triggering caught in the act over the past three decades many researchers have searched for the tidal triggering of earthquakes in the hope that small triggered shocks would illuminate faults critically stressed for failure in future large earthquakes the results have been equivocal but not anymore according to the perspective by stein he highlights a recent paper by tanaka ohtake and sato in earth planets and space where they report the detection of detected tidal triggering in 10 of the japanese archipelago and show that earthquakes are only triggered when the tidal stress acts in the same direction as the regional tectonic stress if the results can be reproduced in places such as california and taiwan a long sought goal of seismology would be achieved

the enigma of the arthur s pass new zealand earthquake 2 the aftershock distribution and its relation to regional and induced stress fields the aftershock distribution of the 1994 arthur s pass earthquake mw6 7 is unusual for a reverse faulting event in that it extends 12 km nnw and 30 km sse of the actual fault plane which strikes ne sw we have used several methods to infer the regional stress field in the region including geodetic results earthquake mechanisms and inversion of p wave polarity data for the stress tensor orientation the inversion method is new and does not require the focal mechanisms of the events used it also incorporates the coulomb failure criterion all results point to a stress field favoring strike slip faulting not thrusting with near horizontal 1 and 3 principal axes striking at 298 and 28 using dislocation theory we calculate the stress induced by the arthur s pass earthquake and its largest aftershock a strike slip event and add this to the regional field there is a fair correspondence between the hypocenters of aftershocks away from the mainshock fault plane and regions of high induced coulomb failure stress cfs on optimally oriented fault planes however there are regions of high induced cfs that are devoid of aftershocks it appears that earthquake slip in this region of oblique 19 plate convergence is as observed elsewhere partitioned into components parallel and perpendicular to the plate margin most of the slip is parallel as occurs on the nearby dextral alpine fault the boundary between the pacific and australian plates however occasional reverse events such as the arthur s pass earthquake account for at least some of the perpendicular component of slip and the uplift that produced the southern alps

classification of rock weathering at writing on stone provincial park alberta canada a study in applied geomorphology at writing on stone provincial park in southern alberta canada weathering is causing deterioration and loss of archaeologically important indian rock art a procedure devised for the use of park personnel identified four classes of weathering ranging from largely unweathered rock to severely weathered the technique employed simple visual qualitative assessment and photo interpretation of 50 sample sections of sandstone cliff face covering a total area of 354 m2 schmidt hammer tests indicated large variations in rock strength and provided a numerical basis for the visual assessment about 43 per cent of the cliffs are severely to completely weathered 41 per cent show moderate weathering

triggering of the 1999 mw 7 1 hector mine earthquake by aftershocks of the 1992 mw 7 3 landers earthquake 1 there is strong observational evidence that the 1999 mw 7 1 hector mine earthquake in the mojave desert california was triggered by the nearby 1992 mw 7 3 landers earthquake many authors have proposed that the landers earthquake directly stressed the hector mine fault our model of the landers aftershock sequence however suggests there is an 85 chance that the hector mine hypocenter was actually triggered by a chain of smaller earthquakes that was initiated by the landers main shock we perform our model simulations using the monte carlo method based on the gutenberg richter relationship omori s law bath s law and assumptions that all earthquakes including aftershocks are capable of producing aftershocks and that aftershocks produce their own aftershocks at the same rate that other earthquakes do in general our simulations show that if it has been more than several days since an m 7 main shock most new aftershocks will be the result of secondary triggering these secondary aftershocks are not physically constrained to occur where the original main shock increased stress this may explain the significant fraction of aftershocks that have been found to occur in main shock stress shadows in static coulomb stress triggering studies

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

extending earthquakes reach through cascading earthquakes whatever their size can trigger other earthquakes mainshocks cause aftershocks to occur which in turn activate their own local aftershock sequences resulting in a cascade of triggering that extends the reach of the initial mainshock a long lasting difficulty is to determine which earthquakes are connected either directly or indirectly here we show that this causal structure can be found probabilistically with no a priori model nor parameterization large regional earthquakes are found to have a short direct influence in comparison to the overall aftershock sequence duration relative to these large mainshocks small earthquakes collectively have a greater effect on triggering hence cascade triggering is a key component in earthquake interactions