Landslides and surficial deposits in urban areas of British Columbia: A review

1982 ◽  
Vol 19 (3) ◽  
pp. 269-288 ◽  
Author(s):  
S. G. Evans
Keyword(s):  
British Columbia ◽  
Urban Areas ◽  
Debris Flows ◽  
Regional Variation ◽  
Slope Failure ◽  
Glacial Till ◽  
Geotechnical Characteristics ◽  
Surficial Deposits ◽  
Glaciomarine Sediments ◽  
Steep Slopes

Landslides in surficial deposits occur commonly in the urban environment of British Columbia. Three groups of surficial materials are especially prone to slope failure. These are glaciomarine sediments, glaciolacustrine deposits, and glacial till that mantles steep mountain slopes. The geological and geotechnical characteristics of these three materials are examined and discussed.The sensitivity, metastable fabric, and geological heterogeneity of glaciomarine sediments control their landslide behaviour. A regional variation in glaciolacustrine deposits is suggested. The Southern Interior and Columbia deposits are dominated by silt varves and those of the Northern Interior by clay varves. The silts are sensitive and collapsible under certain moisture and loading conditions. The effect of urbanisation on these silts in the semiarid Southern Interior is considerable. The retrogressive behaviour of slides in silts and clays in urban areas is also examined.Open-slope and channelled debris flows in till mantles are discussed. They occur mainly on steep slopes in the Coast Ranges as a response to heavy, relief-induced rainfall. The effect of urbanization on slope stability is also discussed.

Landsliding caused by Pleistocene glacial lake ponding–an example from central British Columbia

1987 ◽  
Vol 24 (4) ◽  
pp. 656-663 ◽  
Author(s):  
N. Eyles ◽  
John J. Clague
Keyword(s):  
British Columbia ◽  
Debris Flows ◽  
Large Scale ◽  
Slope Failure ◽  
Glacial Lake ◽  
Fraser River ◽  
Stability Of Slopes ◽  
History Of ◽  
The Stability ◽  
Glacier Advance

Sections cut through the Quaternary sediment fill of the Fraser River valley in central British Columbia provide evidence for large-scale landsliding during Pleistocene time. Especially notable are thick, laterally extensive diamict beds, consisting mainly of Tertiary rock debris, that occur near the base of glaciolacustrine sequences. These beds were deposited by subaqueous debris flows during one or more periods of lake ponding when advancing Pleistocene glaciers blocked the ancestral Fraser River. The association of diamict beds and glaciolacustrine sediments deposited during periods of glacier advance may indicate a genetic link between slope failure and lake filling. These observations (1) demonstrate the adverse effects of high pore pressures on the stability of slopes underlain by poorly indurated Tertiary rocks and (2) extend the known history of landslides involving these rocks back into the Pleistocene. Key words: landslides, debris flows, Pleistocene, glacial lake.

Urban landslides in the vicinity of Vancouver, British Columbia, with special reference to the December 1979 rainstorm

1981 ◽  
Vol 18 (2) ◽  
pp. 205-216 ◽  
Author(s):  
G. H. Eisbacher ◽  
J. J. Clague
Keyword(s):  
British Columbia ◽  
Special Reference ◽  
Urban Areas ◽  
Debris Flows ◽  
Unconsolidated Sediments ◽  
Runoff Water ◽  
Protective Measures ◽  
Local Newspapers ◽  
Debris Avalanches ◽  
Autumn And Winter

Historical landslides in the urbanized Vancouver region, southwestern British Columbia, have almost commonly occurred along escarpments within and at the margins of gently rolling upland surfaces underlain by Pleistocene unconsolidated sediments. The most common and most destructive landslides are debris avalanches and debris flows. They are triggered by intense autumn and winter rainstorms, when water infiltrates and saturates the surficial layer of weathered colluvium. After failure the veneer of debris gains momentum and picks up additional soil and uprooted vegetation. Debris avalanches may temporarily block gullies swollen with runoff water, thus changing into rapidly moving debris flows.A severe rainstorm in December 1979 was accompanied by destructive debris avalanches and debris flows in urban areas in the vicinity of Vancouver. A search of local newspapers and meteorological records back to 1900 indicates that this event was not unique, for at least 26 other comparable storms have triggered landslides in the Vancouver region during this century. Thus it is likely that landslides similar to those of December 1979 will occur repeatedly in the future. The danger of such landslides to life and property will grow if potentially hazardous sites are urbanized without appropriate protective measures.

The Biology of Invasive Alien Plants in Canada. 4. Heracleum mantegazzianum Sommier & Levier

2006 ◽  
Vol 86 (2) ◽  
pp. 569-589 ◽  
Author(s):  
Nicholas A. Page ◽  
Ronald E. Wall ◽  
Stephen J. Darbyshire ◽  
Gerald A. Mulligan
Keyword(s):  
British Columbia ◽  
Urban Areas ◽  
Native Species ◽  
Invasive Plant ◽  
Leaf Shape ◽  
Herbarium Specimens ◽  
Natural Ecosystems ◽  
Alien Plant ◽  
Invasive Alien Plant ◽  
Heracleum Mantegazzianum

Heracleum mantegazzianum (giant hogweed) is an invasive alien plant of management concern in southern Canada where it has escaped from horticulture and established and spread in natural, ruderal, and agricultural ecosystems. It poses a threat to natural ecosystems and human health, and is also a weed in agricultural and urban areas. It is a member of the Carrot family (Apiaceae) and is closely related to the native species Heracleum maximum Bartram (cow-parsnip). It is a monocarpic perennial, which generally flowers in its 3rd or 4th year. Large size, leaf shape, dark reddish pigments in patches on stems and petioles, and fruit characteristics readily distinguish H. mantegazzianum from other plants in Canada. It is increasingly common in riparian areas, floodplains, and forest edges in or near urban areas in southwestern British Columbia and southern Ontario. Based on herbarium specimens, H. mantegazzianum was first recorded in Ontario in 1949, British Columbia in 1964, Nova Scotia in 1980, Quebec in 1990, and New Brunswick in 2000. The development of dense stands of H. mantegazzianum can also reduce the richness of native plants. Contact with H. mantegazzianum can cause phytophotodermatitis, a serious skin inflammation caused by UV photo-activation of furanocoumarins present in the sap. Control methods include herbicide application, mechanical cutting, and animal grazing, but strategies to address seed dispersal and re-establishment from dormant seed must also be adopted. Widespread establishment in southern Canada suggests that eradication is unlikely. However, range expansion and rapid population growth can be prevented through strategic management including public education. Key words: Giant hogweed, Heracleum mantegazzianum, Apiaceae, HERMZ, invasive plant, weed biology, furanocoumarins

scholarly journals Debris-flow susceptibility assessment through cellular automata modeling: an example from 15–16 December 1999 disaster at Cervinara and San Martino Valle Caudina (Campania, southern Italy)

2003 ◽  
Vol 3 (5) ◽  
pp. 457-468 ◽  
Author(s):  
G. Iovine ◽  
S. Di Gregorio ◽  
V. Lupiano
Keyword(s):  
Cellular Automata ◽  
Debris Flow ◽  
Urban Areas ◽  
Debris Flows ◽  
Soil Cover ◽  
Southern Italy ◽  
Landslide Risk ◽  
Campania Region ◽  
Optimal Values ◽  
Debris Flow Susceptibility

Abstract. On 15–16 December 1999, heavy rainfall severely stroke Campania region (southern Italy), triggering numerous debris flows on the slopes of the San Martino Valle Caudina-Cervinara area. Soil slips originated within the weathered volcaniclastic mantle of soil cover overlying the carbonate skeleton of the massif. Debris slides turned into fast flowing mixtures of matrix and large blocks, downslope eroding the soil cover and increasing their original volume. At the base of the slopes, debris flows impacted on the urban areas, causing victims and severe destruction (Vittori et al., 2000). Starting from a recent study on landslide risk conditions in Campania, carried out by the Regional Authority (PAI –Hydrogeological setting plan, in press), an evaluation of the debris-flow susceptibility has been performed for selected areas of the above mentioned villages. According to that study, such zones would be in fact characterised by the highest risk levels within the administrative boundaries of the same villages ("HR-zones"). Our susceptibility analysis has been performed by applying SCIDDICA S3–hex – a hexagonal Cellular Automata model (von Neumann, 1966), specifically developed for simulating the spatial evolution of debris flows (Iovine et al., 2002). In order to apply the model to a given study area, detailed topographic data and a map of the erodable soil cover overlying the bedrock of the massif must be provided (as input matrices); moreover, extent and location of landslide source must also be given. Real landslides, selected among those triggered on winter 1999, have first been utilised for calibrating SCIDDICA S3–hex and for defining "optimal" values for parameters. Calibration has been carried out with a GIS tool, by quantitatively comparing simulations with actual cases: optimal values correspond to best simulations. Through geological evaluations, source locations of new phenomena have then been hypothesised within the HR-zones. Initial volume for these new cases has been estimated by considering the actual statistics of the 1999 landslides. Finally, by merging the results of simulations, a deterministic susceptibility zonation of the considered area has been obtained. In this paper, aiming at illustrating the potential for debris-flow hazard analyses of the model SCIDDICA S3–hex, a methodological example of susceptibility zonation of the Vallicelle HR-zone is presented.

Investigating the controls of submarine landslides and associated hazards in Pangnirtung Fiord, Eastern Baffin Island (Nunavut)

2021 ◽  
Author(s):  
Philip Sedore ◽  
Alexandre Normandeau ◽  
Vittorio Maselli
Keyword(s):  
High Latitude ◽  
Debris Flows ◽  
Slope Failure ◽  
Recurrence Time ◽  
High Recurrence Rate ◽  
Baffin Island ◽  
Submarine Landslides ◽  
Slope Failures ◽  
Near Surface ◽  
Submarine Slope

<p>High-latitude fiords are susceptible to hazardous subaerial and submarine slope failures. Recent investigations have shown that past slope failures in fiords of Greenland and Alaska have generated devastating landslide induced tsunamis. Since coastal communities inhabit these high-latitude fiords, it is critical to understand the slope failure recurrence time, their distribution, potential triggers, and ability to generate tsunamis. In this study, we identified > 50 near-surface submarine landslides in Pangnirtung Fiord, eastern Baffin Island, Nunavut, using multibeam bathymetric and sub-bottom profiler data, along with sediment gravity-cores collected in 2019. Morphometric and morphological analyses, along with sedimentological analyses, were carried out on submarine landslide deposits to quantify their spatial and temporal distribution throughout the fiord and to evaluate the factors that may have triggered the slope failures.</p><p>Combining bathymetric with topographic data from unmanned aerial vehicle imagery, we found that most of these landslide deposits are relatively small (~ 0.08 km<sup>2</sup>) and are associated with outwash fans and steep fiord sidewalls. However, since most slope failure head scarps lie between the intertidal zone and ~30 m water depth, they could not be mapped, which makes it challenging to determine the triggers of the submarine slope failures. Radiocarbon dating reveals that most of these surficial landslide deposits are younger than 500 years old and that they were most likely triggered at different times. This finding highlights a high recurrence rate of slope failures within the fiord, suggesting that localised triggers are responsible for slope failures within the fiord, as opposed to widespread, seismically induced triggers which do not occur as frequently in the study area. In addition, the elongated morphology of the landslide deposits and the varying degrees of landslide deposit surface roughness supports localised point-source triggers. Since most landslides are associated with subaerial outwash fans and deltas, we suggest that triggers of these relatively frequent submarine landslides within Pangnirtung Fiord include rapid floodwater input, subaerial debris flows, and sea-ice loading during low tide.</p><p>This research shows that slope failures in a high-latitude fiord are affected by the interaction of numerous subaerial and submarine processes, leading us to speculate that a potential increase in the frequency of subaerial debris flows and river floods due to climate change may increase the recurrence of submarine landslides.<strong> </strong></p>

A landslide-generated tsunami and outburst flood at Elliot Creek, coastal British Columbia  

2021 ◽  
Author(s):  
Marten Geertsema ◽  
Brian Menounos ◽  
Dan Shugar ◽  
Tom Millard ◽  
Brent Ward ◽  
...  
Keyword(s):  
British Columbia ◽  
Rock Avalanche ◽  
Lake Basin ◽  
Outburst Flood ◽  
Coast Mountains ◽  
Rock Face ◽  
Valley Fill ◽  
Causative Relationship ◽  
Displacement Wave ◽  
Steep Slopes

<p>On 28 November 2020, about 18 Mm<sup>3</sup> of quartz diorite detached from a steep rock face at the head of Elliot Creek in the southern Coast Mountains of British Columbia. The rock mass fragmented as it descended 1000 m and flowed across a debris-covered glacier. The rock avalanche was recorded on local and distant seismometers, with long-period amplitudes equivalent to a M 4.9 earthquake. Local seismic stations detected several earthquakes of magnitude <2.4 over the minutes and hours preceding the slide, though no causative relationship is yet suggested. More than half of the rock debris entered a 0.6 km<sup>2 </sup>lake, where it generated a huge displacement wave that overtopped the moraine at the far end of the lake. Water that left the lake was channelized along Elliot Creek, deeply scouring the valley fill over a distance of 10 km before depositing debris on a 2 km<sup>2</sup> fan in the Southgate River valley. Debris temporarily dammed the river, and turbid water continued down the Southgate River to Bute Inlet, where it produced a 70 km turbidity current and altered turbidity and water chemistry in the inlet for weeks. The landslide followed a century of rapid glacier retreat and thinning that exposed a growing lake basin. The outburst flood extended the damage of the landslide far beyond the limit of the landslide, destroying forest and impacting salmon spawning and rearing habitat. We expect more cascading impacts from landslides in the glacierized mountains of British Columbia as glaciers continue to retreat, exposing water bodies below steep slopes while simultaneously removing buttressing support.</p>

scholarly journals Innovative Seismic Microzonation Maps of Urban Areas for the Management of Building Heritage: A Catania Case Study

Geosciences ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 480
Author(s):  
Glenda Abate ◽  
Simone Bramante ◽  
Maria Rossella Massimino
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Free Field ◽  
Ground Surface ◽  
Seismic Microzonation ◽  
Field Conditions ◽  
Seismic Retrofitting ◽  
Geotechnical Characteristics ◽  
Fixed Base ◽  
Scale Estimate

Several urban areas in the Mediterranean have already been subjected to seismic microzonation studies aimed at determining the acceleration expected on the ground surface, therefore mitigating the associated seismic risks. These studies have been generally related to free-field conditions. The present paper shows innovative seismic microzonation maps based on a large-scale estimate of soil-structure interaction (SSI) effects on design accelerations for some areas characterized by a high seismic risk in Catania, Italy. The proposed procedure combined: (1) geotechnical characteristics; (2) building features; and (3) 1-D seismic response analyses in free-field conditions. The seismic hazard and site effects were evaluated using artificial inputs and inputs recorded recently in Catania. Structural fundamental periods and related spectral accelerations, considering both the fixed-base building configuration and flexible-base configuration, were mapped in the Google My Maps environment. These results showed that SSI often had a beneficial effect, but sometimes it had detrimental effects, especially for some masonry buildings. These maps provided important information for planning the seismic retrofitting of investigated buildings, which were based on more detailed analyses of SSI and the developed maps requiring them.

scholarly journals Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps

2010 ◽  
Vol 10 (3) ◽  
pp. 547-558 ◽  
Author(s):  
L. Marchi ◽  
M. Cavalli ◽  
V. D'Agostino
Keyword(s):  
Urban Areas ◽  
Debris Flows ◽  
Land Use Changes ◽  
Integrated Approach ◽  
Alluvial Fan ◽  
Aerial Photographs ◽  
European Alps ◽  
Alluvial Fans ◽  
Economic Activities ◽  
Hazard Management

Abstract. Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy). Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface.

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