We estimate the elastic thickness of a continental lithosphere by using two approaches that combine the Vening Meinesz-Moritz (VMM) regional isostatic principle with isostatic flexure models formulated based on solving flexural differential equations for a thin elastic shell with and without considering a shell curvature. To model the response of the lithosphere on a load more realistically, we also consider lithospheric density heterogeneities. Resulting expressions describe a functional relation between gravity field quantities and mechanical properties of the lithosphere, namely Young’s modulus and Poisson’s ratio that are computed from seismic velocity models in prior of estimating the lithospheric elastic thickness. Our numerical study in central Eurasia reveals that both results have a similar spatial pattern, despite exhibiting also some large localized differences due to disregarding the shell curvature. Results show that cratonic formations of North China and Tarim Cratons, Turan Platform as well as parts of Siberian Craton are characterized by the maximum lithospheric elastic thickness. Indian Craton, on the other hand, is not clearly manifested. Minima of the elastic thickness typically correspond with locations of active continental tectonic margins, major orogens (Tibet, Himalaya and parts of Central Asian Orogenic Belt) and an extended continental crust. These findings generally support the hypothesis that tectonically active zones and orogens have a relatively small lithospheric strength, resulting in a significant respond of the lithosphere on various tectonic loads, compared to a large lithospheric strength of cratonic formations.

Jordskred är ett naturfenomen som ställer till förödelse och orsakar stora ekonomiska konsekvenser för samhället. Göta Älvdalen är ett av Sveriges mest skredutsatta område där kvickleran på sina håll är utbredd. Kvickleran har en god hållfasthet men vid vibrationer eller annan störning blir den flytande som filmjölk. Sveriges Geologiska Institut, SGI, har kartlagt hela älvdalen där de mest utsatta områdena pekats ut och ett av dessa områden är Lilla Edets tätort. En del av det förebyggande arbetet är övervakning av älvdalsområdet för att på ett tidigt stadium kunna vidta åtgärder för att förhindra att skred uppstår.

Syftet med studien är att titta närmare på möjligheterna att använda terrester laserskanning,under ett kort mätintervall, för jordskredsövervakning i Göta Älvdalen. Området som valts ut i Lilla Edets tätort ligger i direkt anslutning till älven och skannades vid tre tillfällen med en veckas intervall. För georeferering används sfärer och tennisbollar, denna del genomfördes i Trimbles programvara Real Works och de tre punktmolnen jämfördes i sin tur i programvaran Cloud Compare. 

Det granskade resultatet visar inte på markrörelser i området men eftersom sista skanningen genomfördes efter lövsprickning ledde det till att växtligheten ställde till problem. Samma problematik avseende växtlighet belyses i flera andra studier i litteraturgranskningen. Terrester laserskanning är med stor sannolikhet en användbar metod för denna typ av studie men kräver rätt förutsättningar och rätt förarbete.

Considering that Venus has a size very similar to Earth, thermal evolution of both planets should be comparable. Nonetheless, there is no clear evidence of plate tectonics or plate motions on Venus. Instead, various surface deformations attributed to volcanism, resurfacing, localized subduction and other geologic processes were recognized on the planet. In this study we attempt to classify the origin of lithospheric forces on Venus based on using topographic and gravity information. For this purpose, we also estimate the Venusian crustal thickness. In agreement with findings from previous studies, the signature of past or recent global tectonism in the body-force vector pattern on Venus is absent, while exhibiting only regional anomalies. The maximum intensity inferred in the Atla and Beta Regios is likely attributed to mantle upwelling. This is also confirmed by the gravity-topography spectral correlation and admittance analysis that shows the isostatic relaxation of these volcanic regions. The regional body-force pattern in the Bell Regio suggests that a much less pronounced force intensity there is possibly related to crustal load of lava flows. Elsewhere, the body-force intensity is relatively weak, with slightly more pronounced intensity around the Ishtar Terra and the Arthemis Chasmata. The body-force pattern in the Arthemis Chasmata supports the hypothesis that coronae structures are the result of mantle upwelling and the subsequent (localized) plume-induced subduction with only limited horizontal crustal motions. The prevailing divergent pattern of body-force vectors in the Ishtar Terra region suggests the presence of tensional forces due to the downwelling mantle flow that is responsible for a crustal thickening along the Freyja and Maxwell Montes. Except for the Atla and Beta Regios where the isostasy is relaxed by the (active) mantle plumes, the crustal thickness is spatially highly correlated with the topography, with a thin crust under the plains and a thick crust under the plateaus. The maximum Moho depth under the Maxwell Montes in the Ishtar Terra exceeds 90 km.