landslide recognition and mapping in a mixed forest environment from airborne lidar data abstract a precise accurate and complete landslide inventory is indispensable for the establishment of reliable landslide susceptibility and hazard maps in the preparation of landslide inventories dense vegetation cover is the major obstacle that confounds the topographic signature of landslides today the growing usage of light detection and ranging lidar technology in the field of geoscience illuminates the mystery of the landscapes cloaked in dense vegetation by providing a new visual acuity to researchers turkey similar to many mid latitude mountainous countries suffering from landslides is still continuing landslide inventory mapping with conventional methods such as aerial photo interpretations api although 68 of landslide events occurred under dense forest cover in the north of the country despite the country wide medium scaled landslide catalogs the number and the abundance of landslides covered by forests remain largely unknown regardless of the increasing availability of high resolution remote sensing data from these motivating insights and drawbacks the study s focus is to evaluate the capability of mapping landslides by visually analyzing airborne lidar dtm derivatives and compare the results with the 1 25 000 scaled api based inventory to understand the potential contribution of lidar technology in europe s deadliest country turkey in terms of landslides the landslide mapping results for a test area located in the densely forested ulus basin western black sea region reveal that the extent and the number of the mapped landslides n 902 from the airborne lidar data are much higher than those of the available api based landslide inventory which includes 67 landslides comparative analysis on topographic signatures of landslides is also underpinned on a distinct discrepancy of slope failure diagnostic indicators captured by the two available dems derived from lidar and 1 25 000 scaled topographic maps emphasizing the success rate of lidar derived dem in recognition and mapping landslides with higher precision and accuracy together with all analysis results the landslide recognizability degree assessment based on the forest cover percentage and slope height differences of landslides highlights that the lidar data enable landslides to be defined up to 100 m2 while this value is 20 times lower than that of estimated values from api based landslides in addition to underlining the contribution of lidar technology to the recognition of landslides hidden under dense vegetation these findings stress the importance of lidar data on complete and accurate landslide inventories for production of reliable susceptibility and hazard maps and further a better understanding of the landslide processes and reducing related losses

the valpola landslide abstract the large valpola landslide which occurred on july 28 1987 in valtellina central alps italy on the eastern slope of mt zandila is described and analyzed the slide which took place after a period of heavy rainfall involved a slope made up of 34 million cubic meters of fractured igneous rock the rock mass detached between the elevations of 2250 and 1700 m above s l and with the characteristics of a rock avalanche fell approximately 800 m devastating the bottom of the valley over a distance of 4 km and killing 27 people the mass movement was due to the reactivation of a paleoslide triggered by the rise of hydrostatic pressure in the fractured rock mass and by deep erosion along the bed of pola creek in order to mitigate the risks connected with slope instabilities comprehensive surveying and prediction methods are necessary monitoring since july 28 1987 has been very successfull in assisting prediction

the 2001 adana landslide and its destructive effects turkey the current study deals with a catastrophic landslide that occurred due to heavy rainfall in adana southern turkey in 2001 the research area which is one of the largest populated districts in adana and one of the most tropical places between the middle east and southern europe has about 25 000 people on the basis of geological and geotechnical surveys the landslide phenomena and the effects of landslide are examined to understand the slide mechanism of the landslide ground reconnaissance laboratory and in situ tests are conducted it is observed that the clayey and silty layers of the site are heavily saturated due to extreme rainfall in winter and consequently sheared the landslide consists of a block sliding in the upper portions and a debris flow soil flow component around the margins of the sliding blocks in the middle parts and at the toe although there was no loss of human life it has caused significant economic losses besides it is determined that if precautions are not taken around the landslide area larger landslides could definitely occur in the future

volcanic eruptions on io nine eruption plumes were observed over a period of 6 1 2 days during the voyager 1 encounter with io during the voyager 2 encounter 4 months later eight of these eruptions were still active the largest plume viewed by voyager 1 became inactive sometime between the two encounters however a major eruption occurred at surt sometime between the two encounters and deposited an ejecta blanket comparable in size to those associated with the largest plumes the plumes range in height from about 60 to over 300 km with corresponding ejection velocities of about 0 5 to 1 0 km s where topographic information exists plumes 1 and 8 the plume source is located on level plains rather than topographic highs and consists of either fissures or calderas with the exception of plume 1 pele the brightness distribution monotonically decreases from the core to the top of the plume the shape and brightness distribution together with the pattern of the surface deposit of at least plume 3 prometheus can be simulated by a ballistic model in which the ejection velocity is constant 0 5 km s and ejection angles vary from vertical 0 to 55 the brightness distribution of plume 1 is probably better explained by a shock front near the top of the plume numerous surface deposits similar to those associated with active plumes probably mark the sites of recent eruptions the distribution of active and recent eruptions appears to be concentrated in the equatorial regions and indicates the volcanic activity is more frequent and intense in the equatorial regions than the polar regions this suggests that the depositional rate is greater and the surface age younger in the equatorial regions which may account for the darker polar regions the geologic setting of certain plume sources and the very large reservoirs of volatiles required for the active eruptions suggests that sulphur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes

ground based observations of volcanism on io in 1999 and early 2000 ground based observations of volcanism on io during the period of the 1999 and early 2000 galileo close flybys have detected several types of activity providing information which complements the spacecraft observations at loki a brightening began between august 25 and september 9 and continued through february on august 2 a major outburst was observed near 14 n 74 w whose brightness corresponds to an area of approximately 350 km 2 at a temperature of 1100 k observations of eruptions in late june 9906a and in late november 9911a at tvashtar provide temporal and photometric constraints on activity also seen by galileo high resolution adaptive optics images provide further information on the fainter sources distributed across the surface

prolonged impact of earthquake induced landslides on sediment yield in a mountain watershed the tanzawa region japan abstract to determine for how long a landslide affects sediment discharge the sediment yields of 15 check dam basins were compared with the time series of landslide distributions in a mountain basin in the tanzawa region central japan the distribution of sediment yield was quantitatively estimated from deposition in the sediment pools of check dams the relationship between the landslide history and sediment discharge in the nakagawa river basin was examined for an approximately 80 year period two major landslide events occurred during this period the 1923 kanto earthquake and the 1972 disaster caused by heavy rainfall the resulting trend in sediment discharge of the whole basin estimated using reservoir sedimentation in the miho dam at its base was nearly constant with high sediment discharge 2897 m 3 km 2 yr 1 in the intervening quarter century despite the recovery of vegetation on landslide areas in this period comparisons of the landslide distributions resulting from the two disasters the sediment yields of check dam basins and the sediment discharge of the whole basin indicate that recent sediment discharge contains landslide debris that was originated by the kanto earthquake that occurred over 80 years ago thus to understand high sediment discharge it is essential to investigate not only the current basin condition and recent events but also the landslide history of the basin for at least the previous 100 years

spatio temporal analysis of a complex landslide in the northern apennines italy by means of dendrochronology dendrochronology is used to determine the spatial and temporal development of movements in a complex landslide located in the northern apennines the analysis of trees growing on the landslide body enabled us to date their colonisation pattern which starts from the 1920s and increases mainly after 1950 since then sampled trees recorded with growth anomalies the movements involving the landslide body in 1956 1957 1982 1983 1990 1995 and 1998 these movements are reactivations of the main landslide that probably occurred in the last decades of the 19th century in 1980 trees on the upper landslide body were involved in a rock fall due to the expansion of the main scarp microsections cut out from selected tree ring sequences allowed seasonal dating of the highlighted movements which mostly occurred in early spring meteorological and seismic time series were analyzed in order to relate them with reactivations and to search for correlations and triggering events the seismic activity although characterized by low magnitudes could be able either to trigger the movements 1990 or to destabilize the ground where rainfalls could have been playing the first role in triggering the reactivation probably in 1982 1983 and 1995 the other reactivations seem to be linked either to long lasting rainfalls or to monthly rainfall peaks mostly following dry periods

a multistory gigantic subaerial debris flow in an active fault scarp in nw anatolia turkey anatomy mechanism and timing mass instability in the uplifting footwall blocks of normal faults involves a range of regional and local factors including among others climatic setting topography lithology and particularly ground shaking during earthquakes morphological and sedimentological investigations backed by 14c dating on a huge debris flow and its zone of depreciation provided favorable insights for dynamics and causative factors of this mass wasting our observations showed that ismetpasa debris flow with a volume of 96 km 3 involves three individual flows of decreasing significance in the late pleistocene holocene period the primary flow occurred in relation to a huge landslide developed on highly fractured and altered basaltic lavas near the crest of fault scarp c 18 7 ka bp and probably conditioned by high precipitation rates in the early interglacial although most of the blocky debris flow transferred into the neighboring graben to form a 2 km wide debris fan some remnant blocks and flow induced valley side slick

global color variations on io abstract visible and near infrared images of io from the galileo spacecraft reveal a surface more colorful than previously thought red yellow green white and black hues decorate the satellite presumably caused by a varied composition of sulfur compounds and silicates almost a third of io is covered by red and orange materials particularly at polar latitudes above 30 these red regions were scarcely distinguishable in the shorter wavelength voyager observations bright red pyroclastic deposits mark the locations of many hot spots plumes and visible surface changes providing a prominent flag of recent volcanic activity io s equatorial regions are dominated by yellow materials which occupy about 40 of the satellite s surface white and gray materials cover about 27 of io primarily in equatorial areas and in localized deposits at high latitudes these are identified with moderate to coarse grained so2 as mapped by the nims instrument on galileo r w carlson et al 1997 geophys res lett 24 2479 2482 greenish yellow materials in small isolated spots on io s anti jupiter hemisphere were recently discovered in 3 km pixel color imaging from orbit 14 unlike other ionian terrains these regions have a negative near infrared spectral slope suggesting contamination by a nonsulfur component only about 1 4 of io s surface is occupied by dark materials which display a variety of visible colors ranging from black to red and green most dark spots have a shallow spectral absorption feature at 0 9 m suggesting magnesium rich silicates rather than black sulfur little large scale alteration in the global color and albedo pattern has occurred between the voyager and galileo eras 90 of the surface appears unchanged despite the vigorous volcanic activity which must have taken place in the intervening 17 years this suggests that over a time scale of decades the bulk of io s resurfacing is restricted to a few small but persistently active areas

volcanic activity at tvashtar catena io abstract galileo s solid state imager ssi observed tvashtar catena four times between november 1999 and october 2001 providing a unique look at a distinctive high latitude volcanic complex on io the first observation orbit i25 november 1999 resolved for the first time an active extraterrestrial fissure eruption the brightness temperature was at least 1300 k the second observation orbit i27 february 2000 showed a large 500 km 2 region with many small hot regions of active lava the third observation was taken in conjunction with cassini imaging in december 2000 and showed a pele like annular plume deposit the cassini images revealed an 400 km high pele type plume above tvashtar catena the final galileo ssi observation of tvashtar orbit i32 october 2001 revealed that obvious to ssi activity had ceased although data from galileo s near infrared mapping spectrometer nims indicated that there was still significant thermal emission from the tvashtar region in this paper we primarily analyze the style of eruption during orbit i27 february 2000 comparison with a lava flow cooling model indicates that the behavior of the tvashtar eruption during i27 does not match that of simple advancing lava flows instead it may be an active lava lake or a complex set of lava flows with episodic overlapping eruptions the highest reliable color temperature is 1300 k although higher temperatures cannot be ruled out they do not need to be invoked to fit the observed data the total power output from the active lavas in february 2000 was at least 10 11 w

strug landslide in w slovenia a complex multi process phenomenon abstract large rock slides frequently cause secondary unstable phenomena many such instability processes happened after december 2001 when the strug rockslide estimated at 95 000 m3 was triggered above the kosec village near kobarid in the julian alps w slovenia it was initiated at the contact between high permeable calcareous rocks cretaceous scaglia thrusted over nearly impermeable clastic rocks cretaceous flysch soon after the rockslide initiation a rock fall with a volume of 45 000 m3 was initiated within the rockslide the kinetic push of the rock fall caused the movement of a translational soil landslide with a volume of 180 000 m3 that partially slipped into the torrential ravine of the brusnik stream after a sudden drop of 15 m in december 2001 the rockslide average velocity exponentially slowed down to less than 10 m year till the end of 2002 and came to a practical stillstand in 2003 after the rainfall in spring 2002 small debris flows made of clayey gravels with a volume of up to 1000 m3 started to flow from the zone of accumulation of the rock fall over the soil landslide to and along the channel of the brusnik stream in 2002 more than 20 debris flow events were registered the statistical analysis of the measured local rainfall intensities showed that debris flows were initiated at daily rainfall reaching from 20 to 30 mm depending on the antecedent precipitation this value may be taken as a specific hydrologic threshold for this site because in 2003 no more debris flows were registered a conclusion was drawn that debris flow events were rainfall induced but governed on the same time by the availability of rock fall debris in its zone of accumulation

hot spots on io initial results from galileo s near infrared mapping spectrometer the near infrared mapping spectrometer on galileo has monitored the volcanic activity on io since june 28 1996 this paper presents preliminary analysis of nims thermal data for the first four orbits of the galileo mission nims has detected 18 new hot spots and 12 others which were previously known to be active the distribution of the hot spots on io s surface may not be random as hot spots surround the two bright so2 rich regions of bosphorus regio and colchis regio most hot spots seem to be persistently active from orbit to orbit and 10 of those detected were active in 1979 during the voyager encounters we report the distribution of hot spot temperatures and find that they are consistent with silicate volcanism

a survey of io s volcanism by adaptive optics observations in the 3 8 μm thermal band 1996 1999 in this study we analyze a series of images of io obtained with the european southern observatory adaptive optics system adaptive optics near infrared system adonis at 3 8 m from 1996 to 1999 with particular emphasis on the observations carried out in late 1999 in support of the galileo flybys of io use of a new myopic deconvolution method myopic iterative step preserving algorithm mistral especially designed for planetary objects significantly improves the quality and the reliability of the reconstructed images using a simulation of artificial images of io we estimate the extent to which this algorithm is able to prevent noise amplification to better restore sharp edges and to preserve the initial photometry once this algorithm has been applied to our data and the solar reflected background has been subtracted we have 89 images of io available for search and temporal survey of the hot spots over 4 years in most cases the data acquired during two consecutive nights provide an almost global view of the surface of io we identify 20 hot spots for which we determine the coordinates and the brightness at 3 8 m as a function of time more than half of the hot spots were detected on all the images and were considered as persistent particular emphasis has been put on the brightest two hot spots loki and pele for which we obtain a center to limb variation curve a cosine curve for loki and a curve decreasing slightly faster than a cosine law for pele with possible physical interpretations the temporal variations of their activity have been derived over these 4 years and for loki compared with the results of other ground based surveys the variability of the other fainter sources has also been derived but with less accuracy we have also identified a few new hot spots some of which are transient such as a diffuse emission seen in september and november 1999 at the location of the upcoming tvashtar outburst the data are based on observations 58 f 1003 63 s 0260 and 64 s 0661 collected at the european southern observatory in la silla chile

a history of high temperature io volcanism february 1995 to may 1997 ground based observations of io s infrared thermal emission between february 1995 and may 1997 show several discrete brightenings for which we can constrain locations fluxes and durations several of these were brief high temperature events with temperatures up to at least 1500 k similar to but often smaller than the rare outbursts seen previously loki io s most powerful volcano was relatively active before and probably during galileo s december 1995 io flyby was faint during most of 1996 and began a major long lived brightening between february 20 and march 12 1997 thermal emission was not seen from ra patera site of an active plume in galileo images major outbursts were seen on march 2nd and september 27 1995

landslides in the central coalfield cantabrian mountains nw spain geomorphological features conditioning factors and methodological implications in susceptibility assessment abstract a geomorphological study focussing on slope instability and landslide susceptibility modelling was performed on a 278 km2 area in the nalon river basin central coalfield nw spain the methodology of the study includes 1 geomorphological mapping at both 1 5000 and 1 25 000 scales based on air photo interpretation and field work 2 digital terrain model dtm creation and overlay of geomorphological and dtm layers in a geographical information system gis and 3 statistical treatment of variables using spss and development of a logistic regression model a total of 603 mass movements including earth flow and debris flow were inventoried and were classified into two groups according to their size this study focuses on the first group with small mass movements 100 to 101 m in size which often cause damage to infrastructures and even victims the detected conditioning factors of these landslides are lithology soils and colluviums vegetation pasture and topography dtm analyses show that high instabilities are linked to slopes with ne and sw orientations curvature values between 6 and 0 7 and slope values from 16 to 30 bedrock lithology carboniferous sandstone and siltstone presence of quaternary soils and sediments vegetation and the topographical factors were used to develop a landslide susceptibility model using the logistic regression method application of zoom method allows us to accurately detect small mass movements using a 5 m grid cell data even if geomorphological mapping is done at a 1 25 000 scale

active volcanism on io global distribution and variations in activity abstract io s volcanic activity has been monitored by instruments aboard the galileo spacecraft since june 28 1996 we present results from observations by the near infrared mapping spectrometer nims for the first 10 orbits of galileo correlate them with results from the solid state imaging system ssi and from groundbased observations and compare them to what was known about io s volcanic activity from observations made during the two voyager flybys in 1979 a total of 61 active volcanic centers have been identified from voyager groundbased and galileo observations of these 41 are hot spots detected by nims and or ssi another 25 locations were identified as possible active volcanic centers mostly on the basis of observed surface changes hot spots are correlated with surface colors particularly dark and red deposits and generally anti correlated with white so 2 rich areas surface features corresponding to the hot spots mostly calderas or flows were identified from galileo and voyager images hot spot temperatures obtained from both nims and ssi are consistent with silicate volcanism which appears to be widespread on io two types of hot spot activity are present persistent type activity lasting from months to years and sporadic events which may represent either short lived activity or low level activity that occasionally flares up sporadic events are not often detected but may make an important contribution to io s heat flow and resurfacing the distribution of active volcanic centers on the surface does not show any clear correlation with latitude longitude voyager derived global topography or heat flow patterns predicted by the asthenosphere and deep mantle tidal dissipation models however persistent hot spots and active plumes are concentrated toward lower latitudes and this distribution favors the asthenosphere rather than the deep mantle tidal dissipation model

catastrophic mass movement of 1998 monsoons at malpa in kali valley kumaun himalaya india abstract a devastating landslide on 18 august 1998 near malpa village in kali valley of higher kumaun himalaya killed 221 persons the landslide was a complex rock fall debris flow the mass movement generated around one million cubic metres of debris and partially blocked the kali river malpa gad a tributary of kali being blocked completely the rock mass failed primarily due to the near vertical slopes hanging over the valley along joints the formation of structural wedges along the free face the sheared rock mass due to the close proximity of major tectonic planes and the enhanced pore water pressure due to prolonged heavy precipitation in the preceding days the mesoscopic shear zone exhibiting ramp and flat structure in quartzites shows a southward thrust movement that might have generated shear stress in the rocks the slide clearly demonstrates the distressed state of the rock mass in the himalayan region due to the ongoing northward drift of the indian plate

susceptibility assessments of shallow earthflows triggered by heavy rainfall at three catchments by logistic regression analyses abstract sometimes regional meteorological anomalies trigger different types of mass movements in may 1998 the western black sea region of turkey experienced such a meteorological anomaly numerous residential and agricultural areas and engineering lifelines were buried under the flood waters besides the reactivation of many previously delineated landslides thousands of small scale landslides mostly the earthflow type occurred all over the region the earthflows were mainly developed in flysch type units which have already presented high landslide concentrations in this study three different catchments namely agustu egerci and kelemen were selected because they have the most landslide prone geological units of the region the purposes of the present study are to put forward the spatial distributions of the shallow earthflows triggered to describe the possible factors conditioning the earthflows and to produce the shallow earthflow susceptibility maps of the three catchments the unique condition units ucu were employed during the production of susceptibility maps and during statistical analyses the unique condition units numbered 4052 for the agustu catchment 13 241 for the egerci catchment and 12 314 for the kelemen catchment the earthflow intensity is the highest in the agustu catchment 0 038 flow ucu and lowest in the egerci catchment 0 0035 flow ucu logistic regression analyses were also employed however during the analyses some difficulties were encountered to overcome the difficulties a series of sensitivity analyses were performed based on some decision rules introduced in the present study considering the decision rules the proper ratios of ucu free from earthflow 0 ucu including the earthflow 1 for the agustu egerci and kelemen catchments were obtained as 3 6 and 5 respectively also a chart for the proper ratio selection was developed the regression equations from the selected ratios were then applied to the entire catchment and the earthflow susceptibility maps were produced the landslide susceptibility maps revealed that 15 of the agustu catchment 8 of the egerci catchment and 7 of the kelemen catchment have very high earthflow susceptibility and most of the earthflows triggered by the may 1998 meteorological event were found in the very high susceptibility zones

landslide hazard zonation using analytical hierarchy process along national highway 3 in mid himalayas of himachal pradesh india landslide zonation studies emphasize on preparation of landslide hazard zonation maps considering major instability factors contributing to occurrence of landslides this paper deals with geographic information system based landslide hazard zonation in mid himalayas of himachal pradesh from mandi to kullu by considering nine relevant instability factors to develop the hazard zonation map analytical hierarchy process was applied to assign relative weightages over all ranges of instability factors of the slopes in study area to generate landslide hazard zonation map layers in geographic information system were created corresponding to each instability factor an inventory of existing major landslides in the study area was prepared and combined with the landslide hazard zonation map for validation purpose the validation of the model was made using area under curve technique and reveals good agreement between the produced hazard map and previous landslide inventory with prediction accuracy of 79 08 the landslide hazard zonation map was classified by natural break classifier into very low hazard low hazard moderate hazard high hazard and very high landslide hazard classes in geographic information system depending upon the frequency of occurrence of landslides in each class the resultant hazard zonation map shows that 14 30 of the area lies in very high hazard zone followed by 15 97 in high hazard zone the proposed model provides the best fit classification using hierarchical approach for the causative factors of landslides having complex structure the developed hazard zonation map is useful for landslide preparedness land use planning and social economic and sustainable development of the region

along strike variations of p t conditions in accretionary wedges and syn orogenic extension the hp lt phyllite quartzite nappe in crete and the peloponnese syn orogenic detachments in accretionary wedges make the exhumation of high pressure and low temperature metamorphic rocks possible with little erosion the velocity of exhumation within the subduction channel or the accretionary complex and thus the shape of p t paths depend upon the kinematic boundary conditions a component of slab retreat tends to open the channel and facilitates the exhumation we document the effect of slab retreat on the shape of p t paths using the example of the phyllite quartzite nappe that has been exhumed below the cretan syn orogenic detachment during the miocene in crete and the peloponnese data show a clear tendency toward colder conditions at peak pressure and during exhumation where the intensity of slab retreat is larger this spatial evolution of p t gradient is accompanied with an evolution from a partly coaxial regime below the peloponnese section of the detachment toward a clearly non coaxial regime in crete

the impacts of logging on landslide activity at clayoquot sound british columbia abstract the objective of this study was to investigate the impacts of logging on landslide activity in clayoquot sound on the west coast of vancouver island british columbia a total of 1004 landslides were documented in order to test the hypothesis that areas affected by logging activities show different density frequency and magnitude characteristics of landsliding than areas unaffected by logging the frequency of landslides in logged terrain was found to be nine times higher than in undisturbed forest an exponential increase in landslide frequency within the area logged was observed on a large watershed scale failures in logged terrain occur on gentler slopes than in natural terrain partly because fewer slopes steeper than 40 have been logged debris slides and debris flows are the most frequently occurring mass movements initiating mostly from road fill failures and from within cutblocks most landslides initiated on se facing slopes with the highest landslide frequency near the coast and diminishing exponentially further inland this pattern of activity most likely reflects the greater impact of severe storms arriving from the pacific with winds dominating from the southeast concave and straight slopes are most susceptible to landslide initiation a preliminary examination of geologic control on the frequency of landslides suggests that the quatsino formation the island plutonic suite and the sicker group are significantly above the average rate further work is needed to identify and quantify factors confounding the trends and correlations identified in this overview study results obtained in this study will be used to implement changes in forest management

the role of rainfall in the landslide hazard the case of the avigliano urban area southern apennines italy abstract mass movements varying in type and size some of which are periodically reactivated affect the urban area of avigliano the disturbed and remoulded masses consist of sandy silty or silty clayey plastic material interbedded with stone fragments and conglomerate blocks five landslides that were markedly liable to rainfall associated instability phenomena were selected the relationships between landslides and rainfall were investigated using a hydrological and statistical model based on long term series of daily rainfall data the model was used to determine the return period of cumulative daily rainfall over 1 180 days the resulting hydrological and statistical findings are discussed with the aim of identifying the rainfall duration most critical to landslides the concept of a precipitation threshold was generalized by defining some probability classes of cumulative rainfall these classes indicate the thresholds beyond which reactivation is likely to occur the probability classes are defined according to the return period of the cumulative rainfall concomitant with landslide reactivation

discovery of hotspots on io using disk resolved infrared imaging active tidally driven volcanism on jupiter s satellite io1 2 was discovered in voyager images in 1979 voyager also detected the thermal emission from the volcanoes3 4 and this emission has since been monitored from earth using a variety of techniques employing single element infrared detectors5 10 because of io s small angular size no more than 1 2 arcsec however it has normally been possible to resolve and locate only the brightest individual hotspot loki although additional hotspots can be located at five year intervals during occultations of io by the other galilean satellites11 12 here we present first results using two new techniques for ground based observation of io s hotspots first use of an infrared array camera allowed us to exploit the mauna kea observatory s excellent atmospheric stability to obtain direct infrared images of io with resolution better than 0 5 arcsec this allowed us to see more than one hotspot on io in jupiter eclipse in jupiter s shadow second we used the camera to make the first observations of the jupiter occultation disappearance behind jupiter of the hotspots these new techniques have revealed and located at least three hotspots and will now permit routine ground based monitoring of the locations temperatures and sizes of multiple hotspots on io

active volcanism on io as seen by galileo ssi abstract active volcanism on io has been monitored during the nominal galileo satellite tour from mid 1996 through late 1997 the solid state imaging ssi experiment was able to observe many manifestations of this active volcanism including 1 changes in the color and albedo of the surface 2 active airborne plumes and 3 glowing vents seen in eclipse about 30 large scale tens of kilometers surface changes are obvious from comparison of the ssi images to those acquired by voyager in 1979 these include new pyroclastic deposits of several colors bright and dark flows and caldera floor materials there have also been significant surface changes on io during the galileo mission itself such as a new 400 km diameter dark pyroclastic deposit around pillan patera while these surface changes are impressive the number of large scale changes observed in the four months between the voyager 1 and voyager 2 flybys in 1979 suggested that over 17 years the cumulative changes would have been much more impressive there are two reasons why this was not actually the case first it appears that the most widespread plume deposits are ephemeral and seem to disappear within a few years second it appears that a large fraction of the volcanic activity is confined to repeated resurfacing of dark calderas and flow fields that cover only a few percent of io s surface the plume monitoring has revealed 10 active plumes comparable to the 9 plumes observed by voyager one of these plumes was visible only in the first orbit and three became active in the later orbits only the prometheus plume has been consistently active and easy to detect observations of the pele plume have been particularly intriguing since it was detected only once by ssi despite repeated attempts but has been detected several times by the hubble space telescope at 255 nm pele s plume is much taller 460 km than during voyager 1 300 km and much fainter at visible wavelengths prometheus type plumes 50 150 km high long lived associated with high temperature hot spots may result from silicate lava flows or shallow intrusions interacting with near surface so2 a major and surprising result is that 30 of io s volcanic vents glow in the dark at the short wavelengths of ssi these are probably due to thermal emission from surfaces hotter than 700 k with most hotter than 1000 k well above the temperature of pure sulfur volcanism active silicate volcanism appears ubiquitous there are also widespread diffuse glows seen in eclipse related to the interaction of energetic particles with the atmosphere these diffuse glows are closely associated with the most active volcanic vents supporting suggestions that io s atmopshere is dominated by volcanic outgassing globally volcanic centers are rather evenly distributed however 14 of the 15 active plumes seen by voyager and or galileo are within 30 of the equator and there are concentrations of glows seen in eclipse at both the sub and antijovian points these patterns might be related to asthenospheric tidal heating or tidal stresses io will continue to be observed during the galileo europa mission which will climax with two close flybys of io in late 1999

a close up look at io from galileo s near infrared mapping spectrometer infrared spectral images of jupiter s volcanic moon io acquired during the october and november 1999 and february 2000 flybys of the galileo spacecraft were used to study the thermal structure and sulfur dioxide distribution of active volcanoes loki patera the solar system s most powerful known volcano exhibits large expanses of dark cooling lava on its caldera floor prometheus the site of long lived plume activity has two major areas of thermal emission which support ideas of plume migration sulfur dioxide deposits were mapped at local scales and show a more complex relationship to surface colors than previously thought indicating the presence of other sulfur compounds

io s loki patera modeling of three brightening events in 2013 2016 abstract loki patera is one of the most dramatically time variable volcanic features on io exhibiting episodic brightening events every 1 3 years that may produce over 15 of io s global heat flow we observed three such brightening events with adaptive optics imaging at the keck and gemini n telescopes over the course of 70 nights of observation in 2013 2016 the high cadence and multi wavelength nature of the observations provides constraints on models for activity at loki patera the matson et al 2006 model for loki patera as an overturning basaltic magma sea is adapted to fit the observations of all three events in particular we adjust the details of the overturn progression and modify the lava thermal properties to include dependencies on temperature and porosity to improve the fit to the data the preferred models find overturn front propagation velocities of 1 2 1 7 km day corresponding to resurfacing rates of 1500 2200 m2 s the time intervals of 440 540 days between successive events are roughly consistent with the 540 day period calculated by rathbun et al 2002 for events prior to 2001 the best coverage was obtained for the 2016 brightening model fits to this event require a lava bulk thermal conductivity of 0 55 0 75 w m k with the best fit obtained for a value of 0 7 w m k and an average porosity that decreases during cooling for all three events the overturn front appears to propagate around the patera in the clockwise direction opposite to what has been inferred for past brightening events there is evidence that the overturn may be more complex than a single propagating wave perhaps involving multiple simultaneous resurfacing waves as well as portions of the patera that are active even after the nominal bright phase has ended the measured intensities are anomalously low when loki patera is viewed at high emission angles suggestive of topographic shadowing due to a raised area or the edge of the depression in which the magma sea resides

investigation of the nature of slip surface using geochemical analyses and 2 d electrical resistivity tomography a case study from lapseki area nw turkey the nature and subsurface structure of the slip surface of a landslide was studied on the basis of geochemical analyses and 2 d electrical resistivity tomography ert survey head scarp and lateral slip surfaces of the landslide marked by clear slickensided shear planes were composed of the average amounts of clayey silt 32 5 and sand 67 5 energy dispersive x ray spectroscopy edx data revealed the enrichment of si 23 24 fe 12 2 al 9 51 and c 8 34 in the elemental composition of the disturbed slip surface from x ray diffractometry xrd data six main clay types were determined such as volkonskoite halloysite ferrosilite saponite illite and nontronite the ert survey displayed that the landslide developed as a reactivation on the upper part of an old landslide body

mapping so2 frost on io by the modeling of nims hyperspectral images abstract we analyze a collection of hyperspectral images of io acquired by the near infrared mapping spectrometer nims of galileo during the g2 to e16 orbits of jupiter this analysis leads to the geographical distribution and physical characterization of so 2 frost deposits over about three fourths of io s surface these deposits are excellent tracers of various phenomena including volcanic production and emission atmospheric transportation condensation metamorphism irradiation and sublimation that occur throughout the so 2 cycle we assume that the deposits of solid so 2 are optically thick and are geographically mixed with other sulfur bearing compounds we first assess the mean moderate backscattering behavior of the so 2 frost henyey greenstein phase function parameter g 0 27 0 05 using a sequence of spectra at two different locations over a large range of phase angles this behavior may indicate a granular texture with many defects or a fluffy texture second a more systematic inversion of the hyperspectral images is achieved based on a linear spectral model of pure so 2 with variable grain size mixed with a spectrally neutral unit as a result we produce two global mosaics that map so 2 frost coverage and mean grain size so 2 deposits are omnipresent on io s surface at the spatial scale of this study 200 km but the so 2 frost is concentrated within several large areas centered at medium latitudes these so 2 rich regions surface coverage higher than 60 show a longitudinal correlation with plumes located lower in latitude suggesting that these plumes are the principal sources of so 2 gas after a possible dynamic condensation around the plumes or at the equator the gas is remobilized by the solar or thermal fluxes and flows mostly latitudinally toward the coldest and nearest regions devoid of hot spots third the correlation of the distribution and grain size mosaics distinguishes four different so 2 physical units that indicate relative regional variations of condensation metamorphism and sublimation finally comparisons with voyager ultraviolet a s mcewen t v johnson d l matson and l a soderblom 1988 icarus vol 75 pp 450 478 and galileo visible p geissler a s mcewen l keszthelyi r m c lopes gautier j granahan and d p simonelli 1999 icarus vol 140 pp 256 282 observations demonstrate molecular contamination of so 2 at medium and high latitudes and that these contaminated so 2 deposits may be optically thin

tvashtar awakening detected in april 2006 with osiris at the w m keck observatory abstract we detected a volcanic outburst in io s northern hemisphere on 17 april 2006 with the osiris imaging spectrometer at keck and confirmed it was still erupting on 2 june 2006 the eruption which we name 060417a was located in tvashtar paterae 100 km southeast of the february 2000 eruption the observed temperature was 1240 4 k over a surface area of 60 5 km 2 providing a total thermal output of 7 7 0 9 10 12 w

modelling shallow landslide susceptibility a new approach in logistic regression by using favourability assessment a new method for estimating shallow landslide susceptibility by combining geographical information system gis nonparametric kernel density estimation and logistic regression is described specifically a logistic regression is applied to predict the spatial distribution by estimating the probability of occurrence of a landslide in a 16 km2 area for this purpose a gis is employed to gather the relevant sample information connected with the landslides the advantages of pre processing the explanatory variables by nonparametric density estimation for continuous variables and a reclassification for categorical discrete ones are discussed the pre processing leads to new explanatory variables namely some functions which measure the favourability of occurrence of a landslide the resulting model correctly classifies 98 55 of the inventaried landslides and 89 80 of the landscape surface without instabilities new data about recent shallow landslides were collected in order to validate the model and 92 20 of them are also correctly classified the results support the methodology and the extrapolation of the model to the whole study area 278 km2 in order to obtain susceptibility maps

dynamic earth system and ecological controls of rainfall initiated landslides abstract rainfall initiated landslides continue to inflict damages and loss of life throughout the world processes and mechanisms revealed from hydrological geomorphic geotechnical pedological geological hydrochemical and biological investigations have advanced our understanding of these effects on slope stability however the interactions amongst these processes and attributes as they affect the initiation and propagation of landslides are not as well understood too often landslide studies are conducted from only one or at most two of these perspectives moreover while precipitation and hydrology are recognized as dynamic influences the earth system and ecological effects are often assumed to be static we assess the interplay of these processes related to landslides triggered by positive pore water accretion and loss of soil suction each of these conditions arguably requires a different view on the processes that cause slope failure and predictive approaches this review starts from the perspective of dynamic adapting earth and ecological systems and discusses how these attributes relate to landslide initiation mode location and timing specifically the role that large and small scale preferential flow plays in both contributing to and mitigating instability is elucidated including effects of bedrock exfiltration we also examine how and under what conditions these pathways manifest in different soils lithology and landforms the multiple effects of rhizosphere processes on slope stability are discussed including root reinforcement evaporation from canopies and litter layers transpiration and the role of root structure affecting preferential flow paths rainfall initiated landslides involve highly dynamic hydrologic earth surface and ecological processes that persist over a range of spatial and temporal scales however guidance for overcoming these challenges has been elusive a conceptual framework is presented to shed light on these dynamic and interactive processes that should lend insights into why and when certain slopes fail during storms while other seemingly similar slopes do not fail such advances will benefit landslide hazard assessments and disaster responsiveness protocols

dynamics of a complex mass movement triggered by heavy rainfall a case study from nw turkey abstract following a period of heavy precipitation a large and complex mass movement namely the dagkoy landslide occurred in the west black sea region of turkey on may 21 1998 this paper describes the conditioning factors of the landslide and interprets the mass transport processes in terms of a movement scenario geology geomorphology and vegetation cover were considered as the conditioning factors of the failure observations showed that the gently sloping about 10 area is mostly covered by dense forest trees at the crown where the motion initiated significant intersection of the collapsed slope with dip of the local marls seems to have contributed to the formation and geometry of the landslide the distance from the crown down to the toe of the landslide measured more than 600 m with about 0 6 km 3 total earth material displaced the landslide has both a block sliding characteristics in the upper portions and a debris flow soil flow component around the margins of the sliding blocks in the middle parts and at the toe the proposed scenario for the landslide reveals that the movement was initiated near crown as a result of the excess water content in the marls at the end of 3 days of heavy rainfall the early perturbations transverse cracks ridges etc lasted for 6 7 h after which the central part of the zone started to move as a soil flow in which very large intact blocks were transported even though the movement was very rapid 1 2 m min there was no loss of life however the movement destroyed 38 houses one mosque and a considerable amount of farmland

landslide susceptibility mapping of the slopes in the residual soils of the mengen region turkey by deterministic stability analyses and image processing techniques abstract the aim of the present study is to prepare a landslide susceptibility map of a region of about 120 km2 between gokcesu and pazarkoy around mengen nw turkey at approximately 10 km north of the north anatolian fault zone where frequent landslides occur for this purpose mechanisms of the landslides were studied by two dimensional stability analyses together with field observations and the parameters controlling the development of such slides were identified field observations indicated that the failures generally developed within the unconsolidated and or semiconsolidated soil units in forms of rotational successive shallow landslides within the weathered zone in mengen cukurca and sazlar formations although consisting of residual soils capak and gokdag formations do not exhibit landslides as the natural slopes formed on these do not exceed the critical slope angles statistical evaluations and distribution of the landslides on the topographical map showed that such parameters as cohesion angle of internal friction slope relative height orientation of slopes proximity to drainage pattern vegetation cover and proximity to major faults were the common features on the landslides digital images were obtained to represent all these parameters on gray scale on the spot image and on the digital elevation model dem of the area using image processing techniques soil mechanics tests were carried out on 36 representative samples collected from different units and parameters were determined for two dimensional stability analyses basing on sensitivity approach and for the preparation of digital shear strength map in order to determine the critical slope angle values for the residual soils a series of sensitivity analyses were realized by using two dimensional deterministic slope stability analyses techniques for varying values of cohesion angle of internal friction and slope height along with varying saturation conditions according to the results of the sensitivity analyses the mengen formation was found to be most susceptible unit to landslides covering about 33 5 of the region studied in terms of surface area the distribution of the critical slopes were determined by superimposing the critical slope values from sensitivity analyses on slope map of the study area on the other hand iso cohesion and iso friction maps were produced by locating the values of cohesion and internal friction angles in a geographic coordinate system such that they coincide with sample locations on the dem and by further interpolation of the values concerned the pixel values were evaluated in gray scale from 0 to 255 0 representing the lowest pixel value and 255 representing the highest sensitivity analyses on cohesion and angle of internal friction to investigate the effects of these parameters only on stability revealed that cohesion was effective at a rate of 70 by itself while angle of internal friction alone controlled the stability by a rate of 30 the iso cohesion and iso friction maps previously obtained were digitally combined in these rates and a shear strength map was prepared the geographic setting of the study area is such that northern slopes usually receive dense precipitation in relation to this fact about 42 of the landslides are due north thus a slope orientation map was prepared using the dem and slopes facing north were evaluated as being more susceptible to sliding proximity to the drainage pattern was another important factor in the evaluation as streams could adversely affect the stability by either eroding the toe or saturating the slope or both when considered together in conjunction with the field observations faults and landslides showed a close association in the area about 88 of the landslides were detected within an area closer than 250 m to major faults therefore a main discontinuity map was produced using the spot image of the region and proximity to major faults was evaluated as a parameter as most of the landslides developed in areas where the vegetation was rather sparse a vegetation cover map was therefore obtained from the spot image and the areas with denser vegetation were considered to be less susceptible to sliding with respect to the areas with less or no vegetation having prepared the maps accounting for the distribution of critical slopes shear strength properties relative height slope angle orientation of the slopes vegetation cover proximity to the drainage pattern geographic corrections were carried on each of these and a potential failure map was obtained for the residual soils by superimposing all these maps next a classification was performed on the final map and five relative zones of susceptibility were defined when compared with this map all of the landslides identified in the field were found to be located in the most susceptible zone the performance of the method used in processing the images appears to be quite high the zones determined on the map being the zones of relative susceptibility

high temperature silicate volcanism on jupiter s moon io infrared wavelength observations of io by the galileo spacecraft show that at least 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on earth today in at least one case the eruption near pillan patera two independent instruments on galileo show that the lava temperature must have exceeded 1700 kelvin and may have reached 2000 kelvin the most likely explanation is that these lavas are ultramafic magnesium rich silicates and this idea is supported by the tentative identification of magnesium rich orthopyroxene in lava flows associated with these high temperature hot spots

modeling shallow landslides and river bed variation associated with extreme rainfall runoff events in a granitoid mountainous forested catchment in japan abstract in this study we developed an algorithm to predict the long term dynamic behavior of shallow landslides

io s thermal emission from the galileo photopolarimeter radiometer galileo s photopolarimeter radiometer instrument mapped io s thermal emission during the i24 i25 and i27 flybys with a spatial resolution of 2 2 to 300 kilometers mapping of loki in i24 shows uniform temperatures for most of loki patera and high temperatures in the southwest corner probably resulting from an eruption that began 1 month before the observation most of loki patera was resurfaced before i27 pele s caldera floor has a low temperature of 160 kelvin whereas flows at pillan and zamama have temperatures of up to 200 kelvin global maps of nighttime temperatures provide a means for estimating global heat flow

application of physical modelling of debris flow triggering to field conditions limitations posed by boundary conditions abstract debris flows are often triggered by hortonian overland flow during high intensity rainstorms data derived from debris flow trigger zones in the southern french alps were fed into a physical model of debris flow triggering based on takahashi using a monte carlo approach with 1000 runs the results show a wide distribution of safety factor values indicating that physical modelling based on actual field measurements may not always be practical as all safety factor values obtained are well below 1 even though debris flows only occur during very high intensity rainstorms the model used must be inappropriate apparently the composition of the overland flow plays an important role during high intensity rainstorms it usually has a very high sediment content and contains stones this prevents it from flowing through the pores of coarse debris accumulations in the central gully of a trigger zone it will rather run over the debris this situation is more stable than with the fluid flowing through the pores the behaviour switch of the fluid above a certain sediment and stone content thus drastically changes the triggering conditions for debris flows and it is concluded that debris flow triggering in the area requires the occurrence of both overland flow and landsliding

thermal signature eruption style and eruption evolution at pele and pillan on io the galileo spacecraft has been periodically monitoring volcanic activity on io since june 1996 making it possible to chart the evolution of individual eruptions we present results of coanalysis of near infrared mapping spectrometer nims and solid state imaging ssi data of eruptions at pele and pillan especially from a particularly illuminating data set consisting of mutually constraining near simultaneous nims and ssi observations obtained during orbit c9 in june 1997 the observed thermal signature from each hot spot and the way in which the thermal signature changes with time tightly constrains the possible styles of eruption pele and pillan have very different eruption styles from september 1996 through may 1999 pele demonstrates an almost constant total thermal output with thermal emission spectra indicative of a long lived active lava lake the nims pillan data exhibit the thermal signature of a pillanian eruption style a large vigorous eruption with associated open channel or sheet flows producing an extensive flow field by orbit c10 in september 1997 the high mass eruption rate high liquidus temperature at least 1870 k eruption at pillan is the best candidate so far for an active ultramafic magnesium rich komatiitic flow on io a style of eruption never before witnessed the thermal output per unit area from pillan is however consistent with the emplacement of large open channel flows magma temperature at pele is 1600 k if the magma temperature is 1600 k it suggests a komatiitic basalt composition the power output from pele is indicative of a magma volumetric eruption rate of 250 to 340 m3 s 1 although the pele lava lake is considerably larger than its terrestrial counterparts the power and mass fluxes per unit area are similar to active terrestrial lava lakes