the geochemistry of mafic metavolcanics implications for the origin of the devonian massive sulfide deposits at zlate hory czechoslovakia mafic metavolcanic rocks in the area of the zlate hory massive sulfide deposits are interpreted as convergent plate margin basalts and basaltic andesites metamorphosed to the greenschist facies according to the major and trace element compositions the metabasites exhibit island arc tholeiitic to low k calc alkaline composition

a review on natural and human induced geohazards and impacts in karst karst environments are characterized by distinctive landforms related to dissolution and a dominant subsurface drainage the direct connection between the surface and the underlying high permeability aquifers makes karst aquifers extremely vulnerable to pollution a high percentage of the world population depends on these water resources moreover karst terrains frequently underlain by cavernous carbonate and or evaporite rocks may be affected by severe ground instability problems impacts and hazards associated with karst are rapidly increasing as development expands upon these areas without proper planning taking into account the peculiarities of these environments this has led to an escalation of karst related environmental and engineering problems such as sinkholes floods involving highly transmissive aquifers and landslides developed on rocks weakened by karstification the environmental fragility of karst settings together with their endemic hazardous processes have received an increasing attention from the scientific community in the last decades concurrently the interest of planners and decision makers on a safe and sustainable management of karst lands is also growing this work reviews the main natural and human induced hazards characteristic of karst environments with specific focus on sinkholes floods and slope movements and summarizes the main outcomes reached by karst scientists regarding the assessment of environmental impacts and their mitigation

asperities and barriers on the seismogenic zone in north chile state of the art after the 2007 mw 7 7 tocopilla earthquake inferred by gps and insar data the mw 7 7 2007 november 14 earthquake had an epicentre located close to the city of tocopilla at the southern end of a known seismic gap in north chile through modelling of global positioning system gps and radar interferometry insar data we show that this event ruptured the deeper part of the seismogenic interface 30 50 km and did not reach the surface the earthquake initiated at the hypocentre and was arrested 150 km south beneath the mejillones peninsula an area already identified as an important structural barrier between two segments of the peru chile subduction zone our preferred models for the tocopilla main shock show slip concentrated in two main asperities consistent with previous inversions of seismological data slip appears to have propagated towards relatively shallow depths at its southern extremity under the mejillones peninsula our analysis of post seismic deformation suggests that small but still significant post seismic slip occurred within the first 10 d after the main shock and that it was mostly concentrated at the southern end of the rupture the post seismic deformation occurring in this period represents 12 19 per cent of the coseismic deformation of which 30 55 per cent has been released aseismically post seismic slip appears to concentrate within regions that exhibit low coseismic slip suggesting that the afterslip distribution during the first month of the post seismic interval complements the coseismic slip the 2007 tocopilla earthquake released only 2 5 per cent of the moment deficit accumulated on the interface during the past 130 yr and may be regarded as a possible precursor of a larger subduction earthquake rupturing partially or completely the 500 km long north chile seismic gap

nonvolcanic tremor observed in the mexican subduction zone nonvolcanic tremor nvt activity is revealed as episodes of higher spectral amplitude at 1 8 hz in daily spectrograms from the continuous seismological records in guerrero mexico the analyzed data cover a period of 2001 2007 when in 2001 2002 a large slow slip event sse had occurred in the guerrero oaxaca region and then a new large sse occurred in 2006 the tremor burst is dominated by s waves more than 100 strong nvt bursts were recorded in the narrow band of 40 150 km 2 to the south of iguala city and parallel to the coastline depths of nvt hypocenters are mostly scattered in the continental crust between 5 and 40 km depth tremor activity is higher during the 2001 2002 and 2006 sse compared with that for the quiet period of 2003 2005 while resistivity pattern in guerrero does not correlate directly with the nvt distribution gravity and magnetic anomaly modeling favors a hypothesis that the nvt is apparently related to the dehydration and serpentinization processes

a tremor and slip event on the cocos caribbean subduction zone as measured by a global positioning system gps and seismic network on the nicoya peninsula costa rica in may 2007 a network of global positioning systems gps and seismic stations on the nicoya peninsula of northern costa rica recorded a slow slip event accompanied by seismic tremor the close proximity of the nicoya peninsula to the seismogenic part of the cocos caribbean subduction plate boundary makes it a good location to study such events several centimeters of southwest motion were recorded by the gps stations over a period of several days to several weeks and the seismic stations recorded three distinct episodes of tremor during the same time span inversion of the surface displacement data for the depth and pattern of slip on the plate interface shows peak slip at a depth of 25 30 km downdip of the main seismogenic zone estimated temperatures here are 250 300 c lower than in other subduction zones where events of this nature have been previously identified there may also be a shallower patch of slip at 6 km depth these results are significant in that they are the first to suggest that slow slip can occur at the updip transition from stick slip to stable sliding and that a critical temperature threshold is not required for slow slip tremor and low frequency earthquake locations are more difficult to determine our results suggest they occur on or near the plate interface at the same depth range as the deep slow slip but not spatially colocated

new insights on the interseismic active deformation along the north ecuadorian south colombian nesc margin 1 the north ecuadorian south colombian subduction zone was the site of the 1906 mw 8 8 megathrust earthquake this main shock was followed by three large events in 1942 1958 and 1979 whose rupture zones were located within the 500 km long 1906 rupture area acombined onshore andoffshore temporary seismic network covering from thetrench to the andes was deployed during 3 months in the area of large earthquakes in order to obtain a detailed knowledge of the seismic background activity resulting earthquakes location and mechanisms bring new insights on interseismic active deformation distribution in the three main tectonic units of the margin namely the interplate seismogenic zone the fore arc region which is part of the north andean block and the downgoing oceanic nazca plate the interplate seismic activity presents along strike variations suggesting that the seismicity and the associated stress buildup along the plate interface depend on the time elapsed since the last large earthquakes according to our results the updip and downdip limits of the seismogenic zone appear to be located at 12 and 30 km depth respectively shallow to intermediate depth seismicity indicates a slab dip angle of 25 north of the carnegie ridge the wadati benioff plane is defined beneath the fore arc down to 100 km depth facing the ridge the wadati benioff plane extends beneath the andes down to 140kmdepth thisobservationconflictswiththehypothesisofthepresenceofaflatslabat a depth of 100 km facing the ridge in the overlying fore arc region the crustal seismicity occurs down to 40 km depth and is mainly concentrated in a roughly nw se 100 km wide stripe stretching from the coast at about 1 n to the andes the location of this active deformation stripe coincides with observed tectonic segmentation of the coastal domain as evidenced by the presence of an uplifting segment to the south and a subsiding segment to the north of the stripe it also corresponds to a 30 change in the trend of the andes suggesting that the curvature of the volcanic arc might play an important role in the deformation of the fore arc region

interplate coupling in the kanto district central japan and the boso peninsula silent earthquake in may 1996 i studied crustal deformation in the kanto district central japan based on continuous gps data horizontal as well as vertical displacement rate demonstrate significant interaction between the landward kanto block and the philippine sea plate although the subduction effect of the pacific plate is not apparent it is reasonable to consider the entire kanto district is displaced westward due to the interaction with the pacific plate the gps velocity data were inverted to estimate the slip deficit distribution on the sagami trough subduction zone the result delineates a strongly coupled region on the plate interface part of which corresponds to the 1923 kanto earthquake the strongly coupled region is located shallower than 20 km in addition the plate interaction is laterally heterogeneous even in the same depth range implying thermal structure is not the only factor controlling interplate coupling the gps data also detected a silent earthquake event on the interface of the philippine sea slab east of the boso peninsula in the middle of may 1996 the silent rupture propagated over a 50 km 50 km wide area during about a week the maximum slip was approximately 50 mm and the released seismic moment was 4 7 1018nm mw 6 4 there was a small seismicity triggered by this silent event the silent slip was located in the peripheral of the strongly coupled area suggesting that frictional properties and or stress conditions are inhomogeneous on the plate boundary interface

non volcanic tremor associated with the march 2010 gisborne slow slip event at the hikurangi subduction margin new zealand 1 non volcanic tremor accompanies slow slip events at most circum pacific subduction zones previously the hikurangi subduction margin new zealand and the boso peninsula of japan have been noted as exceptions where slow slip which occurs at shallow depth compared to other subduction zones does not generate seismic tremor the lack of tremor observations raises questions whether tremor and slow slip are manifestations of the same process and whether different temperature and pressure conditions influence the physical mechanism of tremor production analysis of seismic data during the march 2010 gisborne slow slip event new zealand reveals that this slow slip event at the northern hikurangi margin is accompanied by tremor with distinctive characteristics compared to local microearthquakes both the gisborne area of new zealand and the boso peninsula of japan are underlain by thick accumulations of sedimentary rocks that likely inhibit the observation of low amplitude tremor due to high attenuation discovery of tremor in new zealand suggests that tremor may always accompany slow slip and that its apparent absence at the boso peninsula the hikurangi margin prior to this study and any future regions discovered to experience slow slip without concurrent tremor may be the effect of highly attenuating sediments

fusion of multi resolution surface terrestrial laser scanning and subsurface geodata ert srt for karst landform investigation and geomorphometric quantification a multi method research design based on terrestrial laser scanning gis geophysical prospecting electrical resistivity tomography refraction seismics and sedimentology is applied for the first time to investigate enclosed karst depressions in an integrated way fusing multi resolution surface and subsurface geodata provides profound insights into the formation geometry and geomorphologic processes of dolines the studied landforms which are located in the dikti mountains of east crete are shown to be filled by loose sediments of thicknesses of up to 30 m that mainly consist of fine grained material overlying solid bedrock at depths below 35 to 45 m by combining subsurface observations with geomorphometric calculations local doline genesis can be traced back to initial collapse of fractured bedrock followed by subsequent infilling with colluvials in order to define crucial methodological requirements and guidelines for data fusion both the impact of different elevation models and the influence of data resolution are assessed surface volumes of depressions derived by the digital surface model are 7 21 higher than the results obtained from the terrain model due to vegetation similarly estimates of infill volume calculated on the basis of geophysical outcomes and elevation data differ by up to 13 calculations of the landforms current volumes i e total surface and subsurface volume however are fairly insensitive to raster resolution hence the distinct geomorphologic properties of landforms e g shape terrain roughness slope inclination substantially determine the geomorphometric analysis of both surface and subsurface data as shown by the findings data fusion to integrate digital terrain geophysical and sedimentological datasets of varied resolutions benefits geomorphologic studies and helps provide a comprehensive image of landforms copyright 2013 john wiley sons ltd

slow slip on the northern hikurangi subduction interface new zealand 1 in october 2002 a surface displacement episode of 20 30 mm magnitude was observed over a 10 day period on two continuous global positioning system gps instruments near gisborne north island new zealand we interpret this to result from slow slip on the northern hikurangi subduction interface using ten years of regional campaign gps 1995 2004 and recent continuous gps data we estimate the recurrence interval for similar events to be 2 3 yrs in november 2004 a similar slow slip event occurred within this recurrence period the 2002 event can be modeled by 18 cm of slow slip near the down dip end of the seismogenic zone on the subduction interface offshore of gisborne the campaign gps data show that the 2002 slow slip event had little effect on regional strain patterns

interseismic coupling segmentation and mechanical behavior of the central chile subduction zone global positioning system gps measurements carried out in chile over the last two decades showed that an entire portion of the nazca south america subduction zone 38 s 24 s was locked over this period of time the induced accumulation of elastic deformation in the upper plate was not released until the recent maule earthquake of 27 february 2010 mw 8 8 that ruptured the southern part of this section locking or coupling between the two plates varies both with depth and along strike here we use our own gps data an updated solution of our extended network in central chile combined with other published data sets to quantify the spatial variations of the coupling that prevailed before the maule earthquake using a simple elastic model based on the back slip assumption we show that coupling variations on the subduction plane are sufficient to explain the observed surface deformation with no need of a sliver in central chile we identify four segments characterized by higher coupling and separated by narrow areas of lower coupling this segmentation is in good agreement with historical and recent seismicity in chile in particular the narrow zones of lower coupling seem to have stopped most large seismic ruptures including maule s these zones are often associated with irregular bathymetric or coastal features fracture zones or peninsulas finally coseismic and early post seismic slip distribution of the maule earthquake occurring either in previously highly or weakly coupled zones map a complex distribution of velocity weakening and velocity strengthening patches on the subduction interface

terrestrial laser scanning and close range photogrammetry for 3d archaeological documentation the upper palaeolithic cave of parpallo as a case study graphic and metric archaeological documentation is an activity that requires the capture of information from different sources accurate processing and comprehensive analysis if monitoring of the state of conservation is required this task has to be performed before intervention during and after the completion of the works in a repetitive way this paper presents the use of terrestrial laser scanning tls in order to effectively produce prior to intervention accurate and high resolution 3d models of a cave with engravings dating back to the upper palaeolithic era the processing of the tls data is discussed in detail in order to create digital surface models the complexity of the cave required the integration of two techniques tls and close range photogrammetry to yield not only traditional drawings such as sections and elevations but also photo realistic perspective views and visual navigation worlds fully operational in 3d environments this paper demonstrates the potential of integrating tls and close range photogrammetry to provide both accurate digital surface models and photo realistic outputs this processed data can be used to systematically improve archaeological understanding of complex caves and relief panels of prehistoric art with tiny engravings

deep structures of the ecuador convergent margin and the carnegie ridge possible consequence on great earthquakes recurrence interval 1 the deep structure of the ecuador subduction zone and adjacent carnegie ridge cr was investigated using on shore off shore wide angle seimics a crustal model obtained by 2 d inversion of traveltimes reveals the overthickened 14 km oceanic crust of the cr that underthrusts the high velocity 6 km s basement of the upper plate margin wedge interpreted as part of the accreted oceanic terranes described on shore the plate interface dips 4 to 10 east from the trench to a depth of 15 km shadow zones observed on the margin obs records are interpreted as a low velocity zone consisting of a thin layer of underthrust sediments and the 3 km thick cr layer 2 whose average seismic velocity of 5 1 km s is slower than that of the margin wedge increased interplate coupling related to the subduction of the thick buoyant cr may account for an apparent local increased recurrence interval between great interplate earthquakes

upper paleozoic oceanic crust in the polish sudetes ndsr isotope and trace element evidence the two main mafic ultramafic complexes outcropping in the polish sudetes around the sowie gory high grade massif mt sleza and nowa ruda have been studied for trace elements and nd sr isotopes upper paleozoic sm nd whole rock isochron ages are obtained for both massifs 353 21 ma 2 with i 8 8 0 1 mt sleza and 351 16 ma with i 8 5 0 1 nowa ruda the high initial nd point to a source characterized by a strong time integrated lree depletion and along with incompatible trace element patterns they substantiate the oceanic derivation of these massifs although a subduction related marginal basin setting cannot be totally precluded trace element and isotopic data rather suggest a normal mid ocean ridge origin for the sudetic ophiolites while these results are in marked contrast with previously inferred precambrian or early paleozoic ages remnants of oceanic crust as young as the early carboniferous are consistent with the local sedimentary record of pelagic facies from the frasnian to the tournaisian and they may provide a suitable explanation for the contrasted evolution displayed by different domains of the sudetes the sudetic ophiolites might tentatively be correlated with the upper paleozoic prasinites of the saxon lineament if a late hercynian ca 150 km dextral offset is assumed along the elbe fracture in that case they might represent the latest stage remnants of an oceanic suture zone between the saxo thuringian and moldanubian zones together with several other examples throughout europe these ophiolites provide compelling evidence for the involvement of oceanic crust and plate tectonic processes in the variscan belt

extended nucleation of the 1999 mw 7 6 izmit earthquake laboratory and theoretical studies suggest that earthquakes are preceded by a phase of developing slip instability in which the fault slips slowly before accelerating to dynamic rupture we report here that one of the best recorded large earthquakes to date the 1999 moment magnitude mw 7 6 izmit turkey earthquake was preceded by a seismic signal of long duration that originated from the hypocenter the signal consisted of a succession of repetitive seismic bursts accelerating with time and increased low frequency seismic noise these observations show that the earthquake was preceded for 44 minutes by a phase of slow slip occurring at the base of the brittle crust this slip accelerated slowly initially and then rapidly accelerated in the 2 minutes preceding the earthquake

a preliminary analysis of failure mechanisms in karst and man made underground caves in southern italy abstract natural and anthropogenic caves may represent a potential hazard for the built environment due to the occurrence of instability within caves that may propagate upward and eventually reach the ground surface inducing the occurrence of sinkholes in particular when caves are at shallow depth the effects at the ground surface may be extremely severe apulia region southern italy hosts many sites where hazard associated with sinkholes is very serious due to presence of both natural karst caves and anthropogenic cavities the latter being mostly represented by underground quarries the pliocene pleistocene calcarenite a typical soft rock was extensively quarried underground by digging long and complex networks of tunnels with time these underground activities have progressively been abandoned and their memory lost so that many apulian towns are nowadays located just above the caves due to urban expansion in the last decades therefore a remarkable risk exists for society which should not be left uninvestigated the present contribution deals with the analysis of the most representative failure mechanisms observed in the field for such underground instability processes and the factors that seem to influence the processes as for example those causing weathering of the rock and the consequent degradation of its physical and mechanical properties aimed at exploring the progression of instability of the cavities numerical analyses have been developed by using both the finite element method for geological settings represented by continuous soft rock mass and the distinct element method for jointed rock mass conditions both the effects of local instability processes occurring underground and the effects of the progressive enlargement of the caves on the overall stability of the rock mass have been investigated along with the consequent failure mechanisms in particular degradation processes of the rock mass as a consequence of wetting and weathering phenomena in the areas surrounding the caves have been simulated the results obtained from the numerical simulations have then been compared with what has been observed during field surveys and a satisfactory agreement between the numerical simulations and the instability processes as detected in situ has been noticed

speleogenesis geometry and topology of caves a quantitative study of 3d karst conduits karst systems are hierarchically spatially organized three dimensional 3d networks of conduits behaving as drains for groundwater flow recently geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns however few studies have been performed to quantitatively define these relationships this paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account in order to study the spatial organization of caves a 3d numerical database was built from 26 caves corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns the database includes 3d speleological surveys for which the speleogenetic context is known allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns vadose branchwork vb water table cave wtc looping cave lc and angular maze am eight morphometric cave descriptors were calculated four geometrical parameters width height ratio tortuosity curvature and vertical index and four topological ones degree of node connectivity and graph indices and ramification index respectively the results were validated by statistical analyses kruskal wallis test and pca the vb patterns are clearly distinct from am ones and from a third group including wtc and lc a quantitative database of cave morphology characteristics is provided depending on their speleogenetic processes these characteristics can be used to constrain and or validate 3d geostatistical simulations this study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes conversely the approach developed here provides proxies to estimate the evolution of the vadose zone to epiphreatic and phreatic zones in limestones from the quantitative analysis of existing cave patterns

supergene processes on ore deposits a source of heavy metals the study of supergene processes i e secondary processes running in ore deposits and driven by thermodynamic nonequilibrium between ore and rock forming minerals and natural waters gasses etc is important in order to understand the migration of heavy metals from ore into their adjacent surroundings the contamination of the local environment can be characterized by the composition of pore waters the pb zn cu ore deposits of zlate hory czech republic have been chosen for a detailed study of pore solutions a simple model has been created to describe the evolution of supergene processes in the ore deposits this model is based on the determination of chemical composition of pore solutions the dilution of pore solutions of such mineral deposits results in acid mine drainage pore solutions can have during specific stages of their evolution relatively high concentrations of cu 0 09 mol kg zn 0 1 mol kg so4 0 8 mol kg and an extremely low ph 1 38 the supergene alteration of pyrite is the most important process determining the character of pore water this reaction causes significant acidification and is a leading source of acid mine drainage the leached zone originates from the interaction of pyrite and limonite increased concentrations of heavy metals and sulfates occur in pore waters the dynamic composition of pore waters within ore deposits undergoing the supergene process can be used to distinguish 1 three main zoneslimonite transition and primary zone and 2 two areas an area with the highest intensity of weathering processes and an area of weathering initiation in these areas the rate of sulfide oxidation is higher as a result of low ph from the study of these zones and areas we can further our knowledge of ore body pore solution acid mine drainage and contamination of the local environment

2010 maule earthquake slip correlates with pre seismic locking of andean subduction zone analysis of seismic data and global positioning system gps observations from the region around the site of the recent magnitude 8 8 maule earthquake in chile have been combined with modelling of the andean subduction zone to build up a detailed image of the event the earthquake occurred at a seismic gap part of the fault that has not experienced a major earthquake since 1835 and it seems to have released most of the stress accumulated since that time the observations suggest that coseismic slip heterogeneity at the scale of single asperities and therefore the seismic potential of future great earthquakes might be anticipated by geodetic observations these authors show evidence for a high coherence between the slip distribution inferred from the 2010 maule earthquake chile and the patchwork of interseismic locking distribution derived from global positioning system observations during the previous decade their work suggests that coseismic slip heterogeneity at the scale of single asperities should indicate the seismic potential of future earthquakes which thus might be anticipated by geodetic observations the magnitude 8 8 maule chile earthquake of 27 february 2010 ruptured a segment of the andean subduction zone megathrust that has been suspected to be of high seismic potential1 2 3 4 5 6 it is the largest earthquake to rupture a mature seismic gap in a subduction zone that has been monitored with a dense space geodetic network before the event this provides an image of the pre seismically locked state of the plate interface of unprecedentedly high resolution allowing for an assessment of the spatial correlation of interseismic locking with coseismic slip pre seismic locking might be used to anticipate future ruptures in many seismic gaps6 7 8 9 10 11 12 given the fundamental assumption that locking and slip are similar this hypothesis however could not be tested without the occurrence of the first gap filling earthquake here we show evidence that the 2010 maule earthquake slip distribution correlates closely with the patchwork of interseismic locking distribution as derived by inversion of global positioning system gps observations during the previous decade the earthquake nucleated in a region of high locking gradient and released most of the stresses accumulated in the area since the last major event in 1835 two regions of high seismic slip asperities appeared to be nearly fully locked before the earthquake between these asperities the rupture bridged a zone that was creeping interseismically with consistently low coseismic slip the rupture stopped in areas that were highly locked before the earthquake but where pre stress had been significantly reduced by overlapping twentieth century earthquakes our work suggests that coseismic slip heterogeneity at the scale of single asperities should indicate the seismic potential of future great earthquakes which thus might be anticipated by geodetic observations

characteristic silent earthquakes in the eastern part of the boso peninsula central japan 1 analysis of global positioning system gps data shows transient crustal deformation in the boso peninsula central japan for about fifty days from october 2002 the southeastward horizontal displacements detected suggest the occurrence of interplate aseismic slip between the philippine sea plate and the north american plate six years after a similar event in 1996 we estimate an area of aseismic slip with moment magnitude mw 6 6 centered off the boso peninsula adjacent to associated seismic activity slip evolution of the 2002 aeismic slip started on october 4 and migrated from north to south for about ten days followed by gradual subsidence and restarting of slip which lasted until december 2 propagating more southward similarities in focal area and slip process between the 1996 and the 2002 events suggest the boso aseismic slips as characteristic silent earthquakes together with the repetitive occurrence of seismic swarm in a similar region every six to seven years a more tightly coupled southern area that did not release enough energy in the 1996 event may have caused the differences in magnitude central slip area and duration between the 1996 and the 2002 events if the hypothesized recurrence interval for strain accumulation is true based on swarm seismicity

seismicity patterns along the ecuadorian subduction zone new constraints from earthquake location in a 3 d a priori velocity model to improve earthquake location we create a 3 d a priori p wave velocity model 3 dvm that approximates the large velocity variations of the ecuadorian subduction system the 3 dvm is constructed from the integration of geophysical and geological data that depend on the structural geometry and velocity properties of the crust and the upper mantle in addition specific station selection is carried out to compensate for the high station density on the andean chain 3 d synthetic experiments are then designed to evaluate the network capacity to recover the event position using only p arrivals and the maxi technique three synthetic earthquake location experiments are proposed 1 noise free and 2 noisy arrivals used in the 3 dvm and 3 noise free arrivals used in a 1 dvm synthetic results indicate that under the best conditions exact arrival data set and 3 dvm the spatiotemporal configuration of the ecuadorian network can accurately locate 70 per cent of events in the frontal part of the subduction zone average azimuthal gap is 289 44 noisy p arrivals up to 0 3 s can accurately located 50 per cent of earthquakes processing earthquake location within a 1 dvm almost never allows accurate hypocentre position for offshore earthquakes 15 per cent which highlights the role of using a 3 dvm in subduction zone for the application to real data the seismicity distribution from the 3 d maxi catalogue is also compared to the determinations obtained in a 1 d layered vm in addition to good quality location uncertainties the clustering and the depth distribution confirm the 3 d maxi catalogue reliability the pattern of the seismicity distribution a 13 yr record during the inter seismic period of the seismic cycle is compared to the pattern of rupture zone and asperity of the mw 7 9 1942 and the mw 7 7 1958 events the mw 8 8 1906 asperity patch is not defined we observe that the nucleation of 1942 1958 and 1906 events coincides with areas of positive simple bouguer anomalies and areas where marine terraces are still preserved on the coastal morphology from north to south 1 the 1958 rupture zone is almost aseismic and is attributed to a zone of high coupling 2 south of the galera alignment perpendicular to the trench the 1942 rupture zone presents moderate seismicity deeper on the seismogenic interplate zone and abutting on the jama cluster to the south this cluster is facing the cabo pasado cap and positive bouguer anomalies on the overriding margin we suspect that this cluster reflects a zone of local asperity partial coupling south of the jama cluster the spherical aseismic zone in the bahia area is interpreted as having a low seismic coupling steady creep motion or slow slip events we suspect that the site that generated the three m 7 events 1896 1956 and 1998 correspond to a small patch of strong coupling to the south in the manta puerto lopez zone the seismicity is mainly organized in earthquake swarms 1998 2002 2005 although slow slip events have been observed in the area vallee et al submitted we infer from the coastline shape the marine terraces and the high positive bouguer anomalies that the seismicity here might reveal a significant amount of seismic coupling

recent crustal deformation and the earthquake cycle along the ecuador colombia subduction zone recent results from global positioning system gps measurements show deformation along the coast of ecuador and colombia that can be linked to the rupture zone of the earthquake in 1979 a 3d elastic boundary element model is used to simulate crustal deformation observed by gps campaigns in 1991 1994 1996 and 1998 deformation in ecuador can be explained best by 50 apparent locking on the subduction interface although there have not been any historic large earthquakes mw 7 south of the 1906 earthquake rupture zone 50 apparent elastic locking is necessary to model the deformation observed there in colombia only 30 apparent elastic locking is occurring along the subduction interface in the 1979 earthquake rupture zone mw 8 2 and no elastic locking is necessary to explain the crustal deformation observed at two gps sites north of there there is no evidence from seismicity or plate geometry that plate coupling on the subduction zone is reduced in colombia however simple viscoelastic models suggest that the apparent reduction in elastic locking can be explained entirely by the response of a viscous upper mantle to the 1979 earthquake these results suggest that elastic strain accumulation is occurring evenly throughout the study area but postseismic relaxation masks the true total strain rate

a silent slip event on the deeper cascadia subduction interface continuous global positioning system sites in southwestern british columbia canada and northwestern washington state usa have been moving landward as a result of the locked state of the cascadia subduction fault offshore in the summer of 1999 a cluster of seven sites briefly reversed their direction of motion no seismicity was associated with this event the sudden displacements are best explained by 2 centimeters of aseismic slip over a 50 kilometer by 300 kilometer area on the subduction interface downdip from the seismogenic zone a rupture equivalent to an earthquake of moment magnitude 6 7 this provides evidence that slip of the hotter plastic part of the subduction interface and hence stress loading of the megathrust earthquake zone can occur in discrete pulses

slow slip and frictional transition at low temperature at the hikurangi subduction zone temperature changes with depth do not appear to be a primary control for either slow slip or fault locking processes at the hikurangi margin north island new zealand both slow slip events and the geodetically observed transition from fault locking to free slip at depth occur at temperatures as low as 100 c shallow portions of faults exhibit brittle stick slip behaviour that gives way to more stable sliding with increasing depth limiting the depths to which earthquake inducing slip can occur the increase of temperature with depth is often assumed to transform friction in the fault from velocity weakening unstable to velocity strengthening stable and to change conditions from brittle to ductile1 2 3 4 5 a temperature of 350 c has been suggested to mark the base of the frictionally unstable portion of the fault which becomes free slipping at depth where temperatures rise above 450 c refs 2 4 6 here we show that both slow slip events and the geodetically observed transition from fault locking to free slip at the hikurangi subduction zone east of the north island new zealand occur at temperatures as low as 100 c suggesting that temperature is not a primary control on either slow slip or fault locking processes at the hikurangi margin although globally shallow slow slip events are rare five out of seven events observed so far at the hikurangi margin are less than 15 km deep

high resolution 3 d mapping using terrestrial laser scanning as a tool for geomorphological and speleogenetical studies in caves an example from the lessini mountains north italy abstract terrestrial laser scanning tls is increasingly used in geomorphology for the study of medium to small scale landforms a light weight compact and portable tls device has been used in the grotta a cave mt lessini n italy to make a detailed 3d model of the underground environment a total of 16 scans were used to survey the about 150 m long cave in

the comparison of strata bound massive sulfide deposits using the fuzzy linguistic diagnosis of the zlate hory deposits czechoslovakia as an example the zlate hory ore deposits as an example of volcanogenic strata bound massive base metal sulfides occurring in the devonian formations of the jeseniky mts are compared with distinctive phanerozoic types representing this type of ore deposit i e with kuroko type rosebery type besshi type and cyprus type deposits the results of comparison performed with fuzzy linguistic diagnosis indicate close resemblance of the zlate hory deposits to rosebery type massive sulfides with regard to primary features however individual features point to certain original similarity with kuroko type deposits too the metamorphic history of the ore deposits studied was similar to that of the rosebery and besshi types

intense interface seismicity triggered by a shallow slow slip event in the central ecuador subduction zone we document a 1 week long slow slip event sse with an equivalent moment magnitude of 6 0 6 3 which occurred in august 2010 below la plata island ecuador south of the rupture area of the 1906 mw 8 8 megathrust earthquake gps data reveal that the sse occurred at a depth of about 10 km within the downdip part of a shallow 15 km isolated locked patch along the subduction interface the availability of both broadband seismometer and continuous geodetic station located at the la plata island 10 km above the sse enables a careful analysis of the relationships between slow and rapid processes of stress release along the subduction interface during the slow slip sequence the seismic data show a sharp increase of the local seismicity with more than 650 earthquakes detected among which 50 have a moment magnitude between 1 8 and 4 1 however the cumulative moment released through earthquakes accounts at most for 0 2 of the total moment release estimated from gps displacements most of the largest earthquakes are located along or very close to the subduction interface with focal mechanism consistent with the relative plate motion while the earthquake sizes show a classical distribution gutenberg richter law with a b value close to 1 the space time occurrence presents a specific pattern first the largest earthquakes appear to occur randomly during the slow slip sequence which further evidence that the seismicity is driven by the stress fluctuations related to aseismic slip moreover the seismicity observed during the sse consists in individual events and families of repeating earthquakes these observations indicate that the stress increment induced by the episodic aseismic slip may lead both to sudden seismic moment release and to progressive rupture within small locked patches this study offers an a posteriori interpretation of the seismogenesis in the central ecuador subduction zone where intense seismic swarms have been regularly observed 1977 1998 2002 and 2005 these swarms have likely been triggered by large magnitude slow slip events

an integrated perspective of the continuum between earthquakes and slow slip phenomena slow slip a mechanism by which faults can relieve stress was thought to be distinct from earthquakes however a global review of slow slip phenomena suggests that instead there is a continuum between the two types of event