They are masses which have been dislodged, by fissures and landslides, from the crater’s walls and have tumbled into the cavity. Pieces of sandstone, limestone and shale occur in the agglomerates mixed with volcanic materials, and very often have been baked and partly recrystallized by contact with the hot igneous rocks and the gases discharged by the volcano. At Vesuvius such blocks of altered limestone are rich in new minerals and are well known to collectors. Agglomerates also are usually full of volcanic bombs. These are spongy globular masses of lava which have been shot from the crater at a time when liquid molten lava was exposed in it, and was frequently shattered by the sudden outbursts of steam. These bombs were more or less viscous at the moment of ejection and by rotation in the air acquired their spheroidal form. They are commonly one or two feet in diameter, but specimens as large as nine or twelve feet have been observed. There is less variety in their composition at any volcanic centre than in the case of the foreign blocks above described.

A review of geological and triggering factors influencing landslide susceptibility: artificial intelligence-based trends in mapping and prediction | International Journal of Environmental Science and Technology | Springer Nature Link # A review of geological and triggering factors influencing landslide susceptibility: artificial intelligence-based trends in mapping and prediction - Review - Open access - Published: 09 September 2025 - Volume 22, pages 17347–17382, (2025) - Cite this article You have full access to this open access article Download PDF Save article View saved research International Journal of Environmental Science and Technology Aims and scope Submit manuscript ## Abstract Landslides are one of the most devastating natural hazards in many regions of the globe and lead to thousands of deaths globally each year. Factors affecting landslides vary in different climates. The complex interaction of geological and triggering factors leads to slope failures and difficulty in landslide prediction. Therefore, this study aimed to do a bibliometric analysis and review of geological and triggering factors used in previous studies for landslide susceptibility mapping an

Complex landslide patterns explained by local intra-unit variability of stratigraphy and structure: Case study in the Tyee Formation, Oregon, USA USGS Publications Warehouse ### Complex landslide patterns explained by local intra-unit variability of stratigraphy and structure: Case study in the Tyee Formation, Oregon, USA Engineering Geology By: and Metrics Cited by publications in Crossref Web analytics dashboard Metrics definitions #### Links - Disclaimer - More information: Publisher Index Page (via DOI) - Open Access Version: Publisher Index Page - Download citation as: RIS| Dublin Core #### Abstract Lithology and geologic structure are important controls on landslide susceptibility and are incorporated into many regional landslide hazard models. Typically, metrics for mapped geologic units are used as model input variables and a single set of values for material strength are assumed, regardless of spatial heterogeneities that may exist within a map unit. Here we describe how differences in bedding thickness, grain size, inferred uniaxial compressive strength, and bedding dip control the inherent susceptibility of slopes to deep-seated failure within a single mapped

arcseconds ( Table 3 ). The rating was rescaled between 0 and 1 for consistency with other model inputs. The rationale for these ratings was that younger rocks tend to be less consolidated than older rocks, and for any given age, sedimentary rocks tend to be weaker than igneous and metamorphic rocks. Nadim et al. also pointed out that even though lava rocks may be strong, volcanic deposits are often made of interbedded weak materials. In addition, chemical weathering and alteration often have a strong effect on volcanic materials, leaving landslide-prone soils and rocks ( Frolova et al. ; Reid et al. 2001 ). Table 3: Lithological classification Material, Age Rating (Nadim et al.) Rescaled Rating Water bodies Null 0.1 Greenland ice cap Unknown 0.1 Extrusive volcanic rocks, Archean-Paleozoic 1 0.2 Endogenous rocks, Archean-Paleozoic 1 0.2 Old sedimentary rocks, Archean-Paleozoic 2 0.4 Extrusive volcanic rocks, Paleozoic-Mesozoic 2 0.4 Endogenous rocks, Paleozoic-Mesozoic 2 0.4 Sedimentary rocks, Paleozoic-Mesozoic 3 0.6 Extrusive volcanic rocks, Mesozoic 3 0.6 Endogenous rocks, Mesozoic-Cenozoic 3 0.6 Sedimentary rocks, Paleozoic-Mesozoic 4 0.8 Extrusive volcanic rocks, Mesozoic-Cenozoic 4 0.8 Extrusive volcanic rocks, Cenozoic 5 1.0 Open in a new tab 2.3. Seismicity Seismicity increases landslide hazard by destabilizing the soil and debris on slopes, introducing additional fracturing that can allow water to penetrate and more rapidly influence the subsurface, and creating steeper or more marginal slopes as a result of seismic shaking and co-seismically triggered landslides ( Keefer 1994 ; Okamoto et al. 2013 ). In addition, tectonically active areas may be prone to increased erosion, due to jointing, graben formation, volcanism, stresses ( Scheidegger and Ai 1986 ), and uplift ( Larsen and Montgomery 2012 ). To describe these effects, vector representations of major faults were obtained from the GMW. The distance to these faults was calculated to create a proxy for

The geotechnical characteristics of landslides on the sedimentary and metamorphic terrains of South-East Nigeria, West Africa | Geoenvironmental Disasters | Springer Nature Link # The geotechnical characteristics of landslides on the sedimentary and metamorphic terrains of South-East Nigeria, West Africa - Published: 17 January 2015 - Open access - Research article - Cite this article - Volume 2, article number 1, (2015) You have full access to this open access article Download PDF Save article View saved research Geoenvironmental Disasters Aims and scope Submit manuscript ## Abstract ### Background Landslides in Nigeria occur in various forms and vary in mode, scale and frequency. The variations appear to be significantly controlled by geologic setting, hence the need to study in detail the distinctive features that differentiate landslides in sedimentary environments from those on metamorphic localities. The aim is to understand the actual features impacted on the landslides by geology, from which future predictions of occurrence and identification of instability could be based. The recognition of features that are characteristic of certain geologic setting may be a ma