We argue here that the introduction of an ethical code of conduct thatfollows the example of the Hippocratic Oath of physicians will helpgeologists to acquire binding awareness of their professional and socialresponsibilities. The ethical behavior and obligations of moderngeologists involve, but are not limited to, the following issues: correctland/environment use and management; respect of truth and science;and protection of the Earth systems, on both the local and global scales,and therefore, of our well-being. We believe that for geoligists, theexplicit acceptance of an ethical code will help to promote: (i) anawareness of their social role, expertise and sense of belonging to aprofessional community; (ii) an understanding of the expectations ofcitizens and society; and (iii) cultural growth, with better use ofresearch and implementation of scientific and professional skills. Allthis should enhance the public recognition of the social mission ofgeologists, which is essential for the well-being of society. Therefore,we suggest that like in the majority of medical schools, ethical trainingshould be a part of the university curriculum for students in geology.

We focus on the use of advanced multi-temporal interferometry (MTI) for mapping and monitoring of ground deformations caused by open-cast mining and hydrocarbon production. We also show how MTI can be exploited to monitor the stability of infrastructure in adjacent areas. Open-cast mines represent a good target for MTI, because they are (1) often very large (from few to tens of km(2)); (2) free of or covered by sparse vegetation; (3) require long-term regular monitoring. The operational deformation monitoring via MTI can now rely on free of charge medium-resolution Sentinel-1 data, consistently and regularly acquired by the European Space Agency (ESA) since 2014. To illustrate the application potential of MTI based on Sentinel-1 data, we present the case study of the Belchatow mine (Poland), one of the largest open-cast mines in Europe. We stress that thanks to wide-area coverage; space-borne MTI represents a cost-effective approach to monitoring ground/slope instability hazards in large open pits, as well as the stability of the associated engineering structures and facilities. On-land oil and gas fields are also often huge and ground deformations induced by their exploitations can be profitably targeted by MTI. This is illustrated through an example of MTI application from the Middle East that relies on high-resolution (3m) radar data. The example highlights the possibility of obtaining extremely dense (spatially continuous) information, which is important for monitoring complex ground deformations caused by oil field exploitation.

Classical applications of the MTInSAR techniques have been carried out in the past on medium resolution data acquired by the ERS, Envisat (ENV) and Radarsat sensors. The new generation of high-resolution X-Band SAR sensors, such as TerraSAR-X (TSX) and the COSMO-SkyMed (CSK) constellation allows acquiring data with spatial resolution reaching metric/submetric values. Thanks to the finer spatial resolution with respect to C-band data, X-band InSAR applications result very promising for monitoring single man-made structures (buildings, bridges, railways and highways), as well as landslides. This is particularly relevant where C-band data show low density of coherent scatterers. Moreover, thanks again to the higher resolution, it is possible to infer reliable estimates of the displacement rates with a number of SAR scenes significantly lower than in C-band within the same time span or by using more images acquired in a narrower time span. We present examples of the application of a Persistent Scatterers Interferometry technique, namely the SPINUA algorithm, to data acquired by ENV, TSX and CSK on selected number of sites. Different cases are considered concerning monitoring of both instable slopes and infrastructure. Results are compared and commented with particular attention paid to the advantages provided by the new generation of X-band high resolution space-borne SAR sensors.

Recently, the Journal, Engineering Geology, celebrated its 50th anniversary.Engineering Geology (referred to hereinafter as "the Journal")was founded in 1965 with the inaugural issue published in August ofthat year. More than 3400 papers have been published in the Journalsince then. To help celebrate the 50th anniversary of the Journal, avirtual special issue (VSI) that consists of thirty selected papers waspublished in 2015 (http://www.journals.elsevier.com/engineeringgeology/).These papers were selected by the two Chief Editors, CarlosCarranza-Torres and Charng Hsein Juang, with the assistance from thepublisher, Kate Hibbert. The selection criteria included citations, the balanceof the subjects, and contributions of individuals to the Journal. Thepreface of the VSIwaswritten by CharngHsein Juang with contributionsfrom selected members of the Editorial Board of the Journal. This shortcommunication, an enlarged version of the preface of the VSI, aims tosummarize the history of the Journal, to discuss the future challengesfaced by the engineering geology communities, and to provide newhorizons for the young practitioners and researchers in this field.

This work reports the results of an accelerometer monitoring aimed at revealing the seismic response ofhillslopes in the town of Qiaozhuang, in Qingchuan County, near the north-eastern end of the fault ruptured duringthe 2008Mw7.9Wenchuan earthquake in Sichuan Province. Serious damage and slope failures were inducedby this earthquake in the town center and on the hills in the peri-urban zone. This suggested the possible occurrenceof amplification phenomena. Five accelerometer stations were emplaced at two topographic reliefs to investigatetheir response to ground motion during the last part of the Wenchuan seismic sequence. About 50aftershocks were recorded, whose magnitude (ML) varied between 1.2 and 5.5 and epicentral distance rangedfroma fewto 90 km. The accelerometer records provided evidence of directional amplification,whichwas investigatedby analyzing the polar diagrams of normalized Arias intensity (Ia) and the horizontal to vertical spectralratios (HVSR). Evidence of the anisotropic dynamic response and site specific resonance frequencies was obtainedfor both topographic reliefs.However, the ground shakingmaximaorientations differed depending on the local geological setting: in one casethey were transversal and in the other case sub-parallel to the relief elongation.No preferential direction of maximum shaking was observed at the site in the valley. Furthermore, evidence ofresonance was derived from the calculation of spectral ratio between the sites on the slope and those at thefoot of the hills. The resonancewasmore pronounced at higher elevations,which suggested a possible occurrenceof topographic amplification. Resonance frequencies were lower (3-5 Hz) on the smaller hill consisting of subverticallylayered phyllites and higher (up to 7 Hz) on the larger hill made mainly of limestones, whereas an oppositerelation between resonance frequency and hill size could be expected from a purely topographic effect.This and the presence of amplification factors larger than 2 suggest that, in addition to topographic effects,local geology also played a significant role in differentiating the site response.

This paper reports on the application of radar satellite data and Persistent Scatterer Inter- ferometry (PS-InSAR) techniques for the detection of ground deformation in the semi-arid loess region of Lanzhou, northwestern China. Compared with Synthetic Aperture Radar Interferometry (InSAR), PS- InSAR overcomes the problems of temporal and geometric de-correlation and atmospheric heteroge- neities by identifying persistent radar targets (PS) in a series of interferograms. The SPINUA algorithm was used to process 40 ENVISAT ASAR images for the study period 2003-2010. The analysis resulted in the identification of over 140000 PS in the greater Lanzhou area covering some 300 km2. The spatial distribution of moving radar targets was checked during a field campaign and highlights the range of ground instability problems that the Lanzhou area faces as urban expansion continues to accelerate. The PS-InSAR application detected ground deformations with rates up to 10mma-1; it resulted in the detection of previously unknown unstable slopes and two areas of subsidence.

The paper presents results of SPINUA (Stable Point Interferometry overUnurbanised Areas) Persistent Scatterers Interferometry (PSI) processing chain to studyEarth surface deformations along the SW coast of the Gulf of Gdañsk, along the SE part ofthe Baltic Sea. As the input for SPINUA techniques 40 descending ERS-1/2 SLC (Frame =251, Track = 36) images from the period 1995-2001 has been used. The area of interest(AOI) includes few cities and several towns, villages and harbors. The low lying coastalareas of the SW part of the Gulf of Gdañsk are at risk of floods and marine erosion. The PSIresults, however, did not reveal the presence of a regional scale, spatially consistent patternof displacements. It is likely that any crustal deformations in the AOI simply do not exceed ±2mm/year, which is the velocity threshold we assumed to distinguish between moving and non-moving persistent scatterers (PS). Importantly,for the most part the urban areas of the main cities (Gdañsk, Gdynia and Sopot) results show ground stability. Nevertheless, significantdownward movements up to several mm/year, are locally noticed in the Vistula river delta - alluvial plain system located in thecoastal zone east of Gdañsk as well as in the inland area west of the Gdañsk city. Indeed, the highest subsidence rates (-12 mm/year)was observed in the Gdañsk petroleum refinery constructed on alluvial sediments. Thus the anthropogenic loading and consolidationof the recent deposits can locally be an important factor causing ground subsidence.

We investigate the instability of slopes in a 15.6 km2 catchment area in the Southern Apennine mountains(Italy) traversed by a mid-slope road and characterized by predominance of clay-rich flysch units. High resolutionmultispectral satellite imagery is used to identify active landslides, to investigate their close associationwith seasonally wet zones (areas covered by free surface-water including ponds, migrating surfacewater,seeps), as well as to guide subsurface hydrogeological investigations. By combining the remotelysensed surface information and the extensive subsurface dataset from over 40 monitoring piezometer boreholeswe demonstrate that many wet zones initially mapped from the IKONOS imagery are indicative of siteswith seasonally persistent very high groundwater levels within landslide-prone slopes and on intermittentlyactive landslides. Where such surface-subsurface water linkage can be established, the appearance of the wetzones (fully saturated ground/soil) resulting from groundwater discharge or seepage can be used as a forewarningsignal of the increased susceptibility to landsliding, since the hillslopes with shallow groundwatertables are generally more prone to failure. The information about changing surface-water conditions retrievedfrom high resolution satellite data timely acquired during rainy seasons can thus provide crucialinput for temporal and spatial landslide hazard assessments. We anticipate that in the near future highresolution optical space-borne remote sensing will become a commonly used tool for monitoring landslideactivity and for providing temporal series of spatial data necessary to improve our understanding of causativeand triggering processes leading to slope failures.

Advanced remote sensing techniques are now capable of delivering more rapidly high quality information that is sufficiently detailed (and cost-effective) for many engineering applications. Here we focus on synthetic aperture radar (SAR), multi-temporal interferometry (MTI). With radar satellites periodically re-visiting the same area, MTI provides information on distance changes between the on-board radar sensor and the targets on the ground (e.g., human-made structures such as buildings, roads and other infrastructure). The detected distance changes are thus interpreted as evidence of ground and/or structure instability. In settings with limited vegetation cover, MTI can deliver very precise (mm resolution), spatially dense information (from hundreds to thousands measurement points/km 2) on slow (mm-cm/year) deformations affecting the ground and engineering structures. Radar satellites offer wide-area coverage (thousands km 2) and, with the sensors that actively emit electromagnetic radiation and thus can "see'' through the clouds, one can obtain deformation measurements even under bad weather conditions. We illustrate the potential of high resolution MTI and explain what this technique can deliver to assist in infrastructure instability hazard assessment. This is done by presenting selected examples of MTI applied to monitor post-construction behavior of engineering structures. The examples are from Italy and include: an earthfill dam, an off-shore vertical breakwater built to protect an oil terminal, city buildings and a highway. We also stress that the current approach to the assessment of instability hazard can be transformed by capitalizing more on the presently underexploited advantage of the MTI technique, i.e., the capability to provide regularly spatially dense quantitative information for large areas where engineering infrastructure may currently be unaffected by instability, but where the terrain and infrastructure history (e.g., aging) may indicate potential for future failures.

The historical variations in landslide activity are investigated in the Rocchetta S. Antonioterritory, where sown fields cover 75% of the total area. The perception of the inhabitants is thatlandsliding has increased in recent years, and climate change has been invoked as a case. However,since 1865 annual precipitation has decreased c. 8% per century in southeastern Italy and local rainfalldata for the 1955-2008 period show high inter-annual variability with statistically uncertain trends. In thesame decades human alterations to the local environment were considerable. To demonstrate theimpacts of land-use changes, detailed landslide and land-use maps spanning the 1976-2006 periodhave been constructed and the spatial-temporal changes in the context of the local precipitationpatterns have been analysed. It is shown that the frequency of landsliding in 2006 was 160% higherthan in 1976, even though both years were comparably wet. The sown fields increased by 46% from1976 to 2006, and the landslide density was 55% higher on the new sown fields; that is, those cultivatedafter 1976. Thus, the higher susceptibility to landsliding is linked to the land-use changes and especiallyto the new ploughing for EU-sponsored wheat cultivation that has taken place on the steeper slopes.

Multi Temporal Interferometry (MTI) stands for advanced synthetic aperture radar differential interferometry (DInSAR) techniques, which include Permanent/Persistent Scatterers Interferometry -- PSInSAR(TM)/PSI and similar methods, as well as Small Baseline Subset -- SBAS and related/hybrid approaches. These techniques are capable to provide wide-area coverage (thousands of km2) and precise (mm-cm resolution), spatially dense information (from hundreds to thousands of measurement points/km2) on ground surface deformations. New MTI application opportunities are emerging thanks to i) greater data availability from radar satellites, and ii) improved capabilities of the new space radar sensors (X-band Cosmo-SkyMed, C-band RADARSAT-2, TerraSAR-X) in terms of resolution (from 3 to 1 m) and revisit time (from 11 to 4 days for X-band acquisitions). This implies greater quantity and quality information about ground surface displacements and hence improved landslide detection and monitoring capabilities. Even though the applicability of MTI to regional and local-scale investigations of slow landslides has already been demonstrated, the awareness of the MTI utility and its technical limitations among landslide scientists and practitioners is still rather low. By referring to recent works on radar remote sensing, many regional and local scale MTI application examples from the geoscience literature and our own studies, we present an up-to-date overview of current opportunities and challenges in this field. We discuss relevant technical constraints and data interpretation issues that hamper the use of MTI in landslide assessment. Then guidelines on how to mitigate MTI technical limitations and avoid erroneous interpretations of radar-derived slope surface deformations are presented for the benefit of users lacking advanced knowledge in SAR applications. Finally, in view of the upcoming radar satellite launches, future perspectives on MTI applications are outlined and recommendations for applied research priorities are suggested. We foresee that with regular globe-scale coverage, improved temporal resolution (weekly or better) and freely available imagery, new radar satellite background missions such as the European Space Agency's Sentinel-1 will guarantee ever increasing and more efficient use of MTI in landslide investigations. Furthermore, thanks to the improved temporal and spatial resolutions of the new generation radar sensors, significant breakthroughs are expected in detailed slope instability process modeling (e.g. kinematic and geotechnical models), as well as in the understanding of spatial and temporal patterns of landslide movement/activity and their relationships to causative or triggering factors (e.g. precipitation, seismic loading).

On 9 April 2000, a 91 Mm(3) rock avalanche occurred in Linzhi Prefecture, Tibet. The event was accompanied by a deafening noise, with the rock mass travelling from a maximum elevation of 5132 m and coming to a rest at an elevation of 2163 m. It formed a landslide dam in the Yigong Zangbo River of some 55 m height, impounding a reservoir of some 2 Gm(3) for a period of 62 days after which it emptied in less than 12 h. This event was a forewarning of a period of frequent geological disasters in China during the start of the 21st century. The ensuing Wenchuan earthquake (surface-wave magnitude M-s 8.0; May 2008), Zhouqu debris flow (August 2010) and Ludian earthquake (M-s 6.7; August 2014) led to the Chinese Government renewing its campaign against geological disasters and it has since invested heavily in scientific research to guide efforts to mitigate the impact of such natural disasters. This thematic set on Landslide Research in China was initiated to highlight this research. This paper provides a brief review of three of the featured subjects and accompanies the five papers published in the thematic set.

We investigate temporal variations in land use and landsliding in a small catchmentcharacterized by the predominance of clay-rich materials and known to be prone to shallowslope failures. The results demonstrate a pronounced change from land use dominated bygrassland pasture (~53 % in 1955) to wheat-based agriculture (~74 % in 2011). Thetemporal series of landslide inventories also indicate significant variations in landslideactivity in the same period. In particular, the highest susceptibility to landsliding has beenregistered in recent years on the sown fields which had initially (1955) been used forpasture and grazing. The data also reveal that with time the steeper and apparently morelandslide-prone slopes with grassland-pasture have been given over to new wheat cultiva-tion. The introduction of ploughing for the new wheat cultivation on the often steep slopesthat had originally been covered by grass is considered to be a significant factor in theincreased susceptibility to landsliding. The negative impact on slope stability can be relatedto the decrease in effective strengths of soil resulting from modification of the existingcover from grass that is present all year to wheat characterized by a few month growthperiod per year, which implies increase in groundwater levels, and mechanical disturbanceof soil caused by tillage. Finally, for the studied period (1955-2011) the local precipitationdata indicated high inter-annual variability without the presence of any statistically signifi-cant trends.

We report on new developments in the application of ambient noise analysis applied to investigate the dynamic response of landslide-prone slopes to seismic shaking, with special attention to the directional resonance phenomena recognised in previous studies. These phenomena can be relevant for seismic slope susceptibility, especially when maximum resonance orientation is close to potential sliding directions. Therefore, the implementation of an effective technique for site response directivity detection is ofgeneral interest. In this regard methods based on the calculation of horizontal-to-vertical noise spectral ratio (HVNR) are promising. The applicability of such methods is investigated in the area of Caramanico Terme (central Italy), where ongoing accelerometer monitoring of slopes with different characteristics offers the possibility of validation of HVNR analysis. The noise measurements, carried out in different times to test the result repeatability, revealed that sites affected by response directivity persistently show major peaks with a common orientation, consistent with the resonance direction inferred from accelerometer data. In some cases such a directivity turned out parallel to maximum slope direction, but this cannot be considered a systematic feature of slope dynamic response. At sites where directivity is absent, the HVNR peaks do not generally show a preferential orientation, with rare exceptions that could be linked to the presence of temporarily active sources of polarised noise. The observed variations of spectral ratio amplitude can be related to temporal changes in site conditions (e.g. groundwater level/soil water content variations affecting P wave velocity and Poisson's ratio of surficial layer), which can hinder the recognition of main resonance frequencies. Therefore, we recommend conducting simultaneous measurements at nearby sites withinthe same study area and repeating measurements at different times in order to distinguish significant systematic polarisation caused by site-specific response directivity from polarisation controlled by properties of noise sources. Furthermore, an analysis of persistence in noise recordings of signals with systematic directivity showed that only a portion of recordings contains wave trains having a clear polarisation representative of site directional resonance. Thus a careful selection of signals for HVNR analysis is needed for a correct characterisation of site directional properties.

The use of earth surface remote sensing in geology is increasing thanks to the continuous development of sophisticated sensors and the improvements in digital image processing techniques. Here we focus on new remote sensing tools and techniques capable of delivering high-resolution data for geologic hazard investigations. These include airborne imaging systems such as UAVs (Uninhabited Aerial Vehicles) and LiDAR (Light Detection and Ranging), as well as new radar sensors onboard of Earth-orbiting satellites. We emphasize the applications of advanced synthetic aperture radar interferometry (InSAR) techniques referred to as multi-temporal interferometry (MTI). With the free imagery availability from the current (since 2014) European Space Agency (ESA) Sentinel-1 mission, MTI can now be more affordably exploited for long-term (years), regular (weekly-monthly), precise (mm) measurements of ground displacements over large areas (thousands of km2). This, in turn, means improved detection and monitoring capability of landslide/slope instability, seismic and volcanic hazards.

We investigate a 15.6 km2 landslide-prone catchment in the Apennine Mountains (southern Italy). The catchment is traversed by an 11 km long mid-slope road, which has been damaged by a large number of predominantly shallow landslides. Laboratory tests showed that slope materials, derived predominantly from clay-rich flysch units, have poor geotechnical properties (effective residual friction median values around 11°, effective residual cohesion close to zero). Slope stability analyses were first conducted of representative failed slopes traversed by the road, and for which geotechnical parameters were directly available from the laboratory tests. Site-specific slope stability modelling was carried out following a limit equilibrium method for the determination of a factor of safety. Parametric analysis revealed that the stability of slopes is critically dependent on the groundwater conditions. This is consistent with recurrent episodes of landslide reactivation during particularly wet seasons characterized by periods of high groundwater levels, as documented by in situ monitoring. The evaluation of the site-specific models has enabled extending the slope stability analysis to the full hillslope and wider catchment scales. This was done by exploiting PESERA-L, a freeware software developed to assist in shallow landslide hazard assessment in watersheds. The produced landslide probability maps, fine-tuned and tested using, respectively, the 2006 and 2011 landslide inventories, improve our understanding of differences in susceptibility to slope failure throughout the catchment.

The PSI (Persistent Scatterer Interferometry) processing of ENVISAT ASAR data (period 2003-2010) provided spatially dense information (more than 400 PS/km2) on ground surface displacements in Lanzhou, capital of Gansu Province, NW China. The geomorphological and geological context of the local Yellow River valley indicate that the lower, flat areas with floodplain and valley-fill deposits (Holocene terraces with mainly reworked loess at the surface) are stable, whereas some higher, gently sloping valley sides appear locally unstable, particularly where the Late Pleistocene terraces are covered by young aeolian (Malan) loess. The PS velocity data suggest that the relative susceptibility to ground and slope instabilities is the highest on the 4th and 5th order river terraces. This is consistent with the presence of collapsible Malan loess and recent land use of these terraces involving irrigation and construction.

Persistent scatterer synthetic aperture radar interferometry (PS-InSAR) is a remote sensing method that can be used to detect surface deformation, which is an indicator of potential geohazards. By capturing such deformations over time, it is possible to obtain valuable information regarding geohazards such as landslides. This study focused on the use of PS-InSAR to investigate the distribution and causes of surface deformation in the Lanzhou region of Gansu Province in China. Between 2003 and 2010, 41 advanced synthetic aperture radar images were captured by the Envisat satellite and analyzed using PS-InSAR, and the correlation between the observed surface deformation and topographic, geologic, and anthropogenic factors was derived based on a geographic information system platform. It was found that the largest number and highest density of surface deformations occurred at elevations of 1486-1686 m. It was also established that slope ranges of 25°-30° and 35°-40° are threshold values at which surface deformation changes abruptly, and that slopes with north and northwest aspects are most prone to surface deformation. The lithologies most susceptible to surface deformation are clay, sandy soil, and loess. The normalized difference vegetation index indicated that surface deformation occurred most often in areas with sparse vegetation. Anthropogenic activities, e.g., construction and wastewater discharge, could be inferred as causal mechanisms of surface deformation. Comparison of the distributions of geohazards and surface deformation showed considerable consistency, which proves surface deformation can induce geohazards. These results could help governments improve urban planning and geohazard mitigation.

The Mw 7.9 Wenchuan earthquake of May 12th, 2008 shattered and induced failures on hillslopes surrounding the centre of the town of Qiaozhuang, located 250 Km NE of the mainshock epicentre. This motivated investigations on the possible occurrence of site amplification phenomena. The initial efforts involved a temporary accelerometer monitoring carried out between April and October 2009 on Weigan hill and Mount Dong, located SW and NE of the Qiaozhuang centre, respectively. The monitoring results revealed that the local geological setting, characterised by Silurian phyllites with sub-vertical schistosity (at Weigan) and by fractured Precambrian limestones (at Dong), exert major influence on the slopes resonance phenomena, with a secondary contribution due to the topographic setting. To extend the investigation on local slope response, a series of ambient noise recordings were conducted at several sites of the two hills, as well as at Mount Shizi (located NW of the town centre), which is topographically and geologically similar to Mount Dong. The focus was on the sites monitored by accelerometer stations, whose seismic records provided the opportunity to validate the outcomes of ambient noise analysis. Noise data were analysed using two approaches: the standard Nakamura's method and a new technique based on analysis of instantaneous polarization properties, aimed at estimating ellipticity of Rayleigh waves. Data interpretation was hampered by a contingent factor, i.e. environmental conditions characterised by a strong persistent E-W polarized noise at low frequencies (below 1 Hz), and by the complex of geologic and geomorphic conditions. The latter, particularly in the case of Weigan hill, appear responsible for a considerable amplification of vertical ground motions. The repeated recordings and the comparison of the outcomes of the two techniques of noise analysis with the accelerometer data showed that the new technique provides more stable and consistent results. Furthermore, the new technique was able to reveal site resonance properties that Nakamura's method fails to recognise because of transient overlapping of different type waves. Overall, the ambient noise analysis provided evidence of i) low frequency resonance (~1 Hz) acting at the scale of the entire relief (on Weigan Hill), ii) directional amplifications at intermediate frequencies (~4 Hz) affecting ridge crests made of fractured limestone (on Mounts Dong and Shizi), and iii) higher frequency resonances (7-20 Hz), which vary at a very local scale. This information is relevant for inferring the susceptibility of local slopes to earthquake-induced failures, and hence for the collateral seismic hazard assessment in the Qiaozhuan peri-urban areas.

We explore new possibilities offered by the recently available X-band satellite radar sensors for landslidehazard assessments on a detailed scale, with particular reference to the exploitation of Persistent ScatterersInterferometry (PSI) techniques. Special attention is paid to the impact of the improved resolution of new Xbandradar imagery on the PSI results, in terms of quality and quantity of useful information. This evaluationis supported by theoretical modelling as well as by the comparison of results from X-band (CSK) and C-band(ENVISAT) PSI for two areas of interest: one in Italy and the other in Switzerland. It is demonstrated that withrespect to medium resolution ENVISAT PS processing, fewer CSK high resolution images are sufficient toachieve comparable precision of the mean displacement velocity estimates. This, together with the shorterrevisit times provided by the CSK constellation, can be very important when dealing with emergency situations.Furthermore, it is quantified that from about 3 to 11 times greater PS densities are obtained with thehigher resolution X-band data. This implies more information about ground surface displacements as wellas improved landslide monitoring and slope instability investigation capabilities. Furthermore, ground displacementmeasurements can be interpreted without local knowledge of the focus area or in situ controls,and, nonetheless, guide single hillslope instability assessments with support of Google Earth and its high resolutionoptical imagery. This "blind" approach will allow one to monitor remote and poorly known regions athigh risk of potentially disastrous slope failures.

Earthquake induced slope failures are responsible for a significant amount of life loss and damage, and their effective mitigation requires further advancements in our comprehension of slope behaviour under seismic shaking. One source of uncertainty in seismic landslide susceptibility assessment is the phenomenon of enhanced amplification of ground motion along down slope directions. This implies a strength demand beyond that estimated by standard slope stability analysis. An extensive accelerometer monitoring of slope dynamic response in areas exposed to seismic landslide hazard is unfeasible. An alternative approach can take advantage of recent development of reconnaissance techniques based on the analysis of ambient noise recorded by portable instruments. The most popular technique, known as Nakamura or HVNR method, consists in analysing H/V spectral ratios between Horizontal and Vertical components of Noise Recording, and allows the recognition of site resonance frequencies. The application of HVNR to complex site conditions typical of marginally stable slopes is often difficult and requires the development of "ad hoc" procedures both for acquisition and analysis of noise recording. Tests in different geologic and geomorphic settings show that an analysis of azimuthal variation of spectral ratios can reveal the presence and orientation of directional resonance, whereas the recognition of main resonance frequencies requires a proper selection of signals to be analysed. Efforts to evaluate amplification factors currently rely on numerical simulations, which in turn require S-wave velocity of slope materials. Ambient noise analysis in terms of velocity models can contribute through the inversion of H/V spectral ratios and surface wave velocity dispersion curves derived from the processing of multiple simultaneous noise recordings. However these applications require a correct identification of the nature of surface waves present in the noise recording. © 2014 Elsevier B.V. All rights reserved.

The 2008 M w 7.9 Wenchuan Earthquake (Sichuan, China) was possibly the largest and most destructive recent earthquake as far as the geo-hazards are concerned. Of the nearly 200,000 landslides triggered originally, many remobilized within a few years after the initial event by rainfall, which often caused catastrophic debris flows. The cascades of geo-hazards related to the Wenchuan Earthquake motivated research worldwide to investigate the triggering and mechanisms of co-seismic landslides, their rainfall-induced remobilization, the generation of debris flows, the evolution of their controlling factors, and the long-term role of earthquakes in shaping the topography. On the eve of the 10th anniversary of the 2008 Wenchuan Earthquake, we present a short review of the recent advances in these topics, discuss the challenges faced in the earthquake-related geo-hazards mitigation practice, and suggest priorities and guidelines for future research.