The selection of the Discovery Program InSight landing site took over four years from initial identification of possible areas that met engineering constraints, to downselection via targeted data from orbiters (especially Mars Reconnaissance SPAC 11214 layout: Small Condensed v.2.1 file: spac321.tex (ELE) class: spr-small-v1.2 v.2016/06/09 Prn:2016/12/02; 14:37 p. 1/91» « d o c to p i c : R e v i e w P a p e rn u m b e r i n g s t y l e : C o n t e n t O n l yr e f e r e n c e s t y l e : a p s » latitude (initially 15°S-5°N and later 3°N-5°N for solar power and thermal management of the spacecraft), ellipse size (130 km by 27 km from ballistic entry and descent), and a load bearing surface without thick deposits of dust, severely limited acceptable areas to western Elysium Planitia. Within this area, 16 prospective ellipses were identified, which lie ∼600 km north of the Mars Science Laboratory (MSL) rover. Mapping of terrains in rapidly acquired CTX images identified especially benign smooth terrain and led to the downselection to four northern ellipses. Acquisition of nearly continuous HiRISE, additional Thermal Emission Imaging System (THEMIS), and High Resolution Stereo Camera (HRSC) images, along with radar data confirmed that ellipse E9 met all landing site constraints: with slopes <15°at 84 m and 2 m length scales for radar tracking and touchdown stability, low rock abundance (<10 %) to avoid impact and spacecraft tip over, instrument deployment constraints, which included identical slope and rock abundance constraints, a radar reflective and load bearing surface, and a fragmented regolith ∼5 m thick for full penetration of the heat flow probe. Unlike other Mars landers, science objectives did not directly influence landing site selection. AUTHOR'S PROOF

Glacial retreat in recent decades has exposed unstable slopes and allowed deep water to extend beneath some of those slopes. Slope failure at the terminus of Tyndall Glacier on 17 October 2015 sent 180 million tons of rock into Taan Fiord, Alaska. The resulting tsunami reached elevations as high as 193 m, one of the highest tsunami runups ever documented worldwide. Precursory deformation began decades before failure, and the event left a distinct sedimentary record, showing that geologic evidence can help understand past occurrences of similar events, and might provide forewarning. The event was detected within hours through automated seismological techniques, which also estimated the mass and direction of the slide - all of which were later confirmed by remote sensing. Our field observations provide a benchmark for modeling landslide and tsunami hazards. Inverse and forward modeling can provide the framework of a detailed understanding of the geologic and hazards implications of similar events. Our results call attention to an indirect effect of climate change that is increasing the frequency and magnitude of natural hazards near glaciated mountains.

No abstract

No abstract

Coseismic landslides are observed in higher concentrations around surface-rupturing faults. This observation has been attributed to a combination of stronger ground motions and increased rock mass damage closer to faults. Past work has shown it is difficult to separate the influences of rock mass damage from strong ground motions on landslide occurrence. We measured coseismic off-fault deformation (OFD) zone widths (treating them as a proxy for areas of more intense rock mass damage) using high-resolution, three-dimensional surface displacements from the 2016 Mw 7.8 Kaikōura earthquake in New Zealand. OFD zones vary in width from ~50 m to 1500 m over the ~180 km length of ruptures analyzed. Using landslide densities from a database of 29,557 Kaikōura landslides, we demonstrate that our OFD zone captures a higher density of coseismic landslide incidence than generic “distance to fault rupture” within ~650 m of surface fault ruptures. This result suggests that the effects of rock mass damage within OFD zones (including ground motions from trapped and amplified seismic waves) may contribute to near-fault coseismic landslide occurrence in addition to the influence of regional ground motions, which attenuate with distance from the fault. The OFD zone represents a new path toward understanding, and planning for, the distribution of coseismic landslides around surface fault ruptures. Inclusion of estimates of fault zone width may improve landslide susceptibility models and decrease landslide risk.

Abstract. Modeling suggests that steep coastal regions will experience increasingly rapid erosion related to climate change induced sea level rise. Earthquakes can also cause intense episodes of coastal cliff retreat, but coseismic failures are rarely captured in the historical record used to calibrate most cliff retreat forecast models. Here, we disaggregate cliff-top retreat related to strong ground motion and non-seismic sources, providing a unique window into earthquake contributions to long-term coastal cliff retreat. Widespread landsliding and up to c. 19 m of coastal cliff-top retreat occurred in the area of Conway Flat during the 2016 Kaikōura (New Zealand) earthquake despite relatively low (c. 0.2 g) peak ground accelerations. While coastal cliff-top retreat has been spatially and temporally variable over the past 72 years, historical aerial imagery suggests that large earthquake induced landslide triggering events disproportionately contribute to an average 0.25 m/year retreat at Conway Flat. The 2016 Kaikōura earthquake represents c. 24 % of the total cliff-top retreat over the past 72 years and c. 39 % of cliff-top retreat over the past 56 years. Additionally, significant retreat between 1950 and 1966 is likely the result of local seismicity. Together these two events account for c. 57 % of cliff-top retreat over the past 72 years. Earthquake-related debris piles at the base of the cliffs have been rapidly eroded in the 5 years since the 2016 Kaikōura earthquake (more than 25 % loss of debris volume) and there will likely be little evidence of the earthquake within the next decade. In regions with similar lithologic and coastal conditions, evidence of past widespread single-event cliff-top retreat may be limited or non-existent. The coastal cliffs at Conway Flat demonstrate the potential to significantly underestimate future cliff-top retreat using historical records.

No abstract

&lt;p&gt;The 2016 Mw 7.8 Kaik&amp;#333;ura earthquake on New Zealand&amp;#8217;s South Island triggered c. 30,000 landslides. Around 70% of landslides occurred in Torlesse greywacke rock mass, which is characterised by closely spaced but low-persistence joints. Most failures in this rock mass were relatively shallow rock avalanches which do not appear to follow traditional failure mechanism models. Here, we use detailed site characterisation and dynamic numerical modelling to better understand landslide hazard and risk from Torlesse greywacke slopes. Using multi-method site characterisation including 3D pixel tracking in pre- and post-earthquake aerial imagery, geomorphic mapping, rock mass characterisation, geophysical ground investigations and a geotechnical borehole, we developed engineering geological ground models for individual sites. We then used these to develop a conceptual framework of failure mechanism in Torlesse greywacke and propose a &amp;#8216;joint-step-path&amp;#8217; failure mechanism in which rupture surface propagation occurs along pre-existing, but low-persistence joints through multiple degrees of kinematic freedom. Torlesse greywacke failures typically evolve in three main landslide failure stages &amp;#8211; incipient, transitional and rock avalanching. Hazard can increase for the same slope when it transitions from the incipient failure stage to sliding and/or avalanching. To quantify the transition between failure stages, we analysed coseismic displacement and strain for six landslides. As many displacement based coseismic landslide susceptibility models require some threshold, above which the slope is assumed to transition into a landslide, this information could potentially serve as a useful tool. For slopes at the incipient and transitional stage, 1D maximum total strain appears to be closely correlated with source slope angle. Based on these results, we develop the &amp;#8216;transitional slope strain index&amp;#8217; (TSSI) that combines 1D maximum total strain with source slope angle. The TSSI relates to the likelihood of a slope transitioning into a more mobile, and therefore more hazardous, rock avalanche at a given level of earthquake shaking. Dynamic numerical back-analysis of the initiation of two landslides in Torlesse greywacke supports our empirical hypotheses that landslide susceptibility in this rock mass is strongly influenced by slope angle and rock mass strength. Coseismic failure initiation is, furthermore, strongly dependent on ground motion input. The geometry of failures can be reproduced using a random Voronoi joint network and adopting residual joint strength parameters, which further lends weight to the &amp;#8216;joint-step-path&amp;#8217; failure mechanism hypothesis.&lt;/p&gt;