Ever wondered how a rockslide might taste? The Apremont wine variety may be the closest you can get. The grapes are grown on the debris of a large rock avalanche from Mont Granier in the Chartreuse mountains, France. The flavour is a distinctively light and dry with floral, mineral characters.
A catastrophic landslide occurred in 1248. A large portion of the mountain failed, forming a rock avalanche covering the valley and several villages. Some reports state the debris covered more that 6 x 6 km, and destroyed 7 villages. Fatality estimates vary from 1000 to 7000, based on various records made by monks at the time. The failure followed relentless rain which saturated the limestone in the upper portion of the slope, causing a failure along the interface with marl below (source).Continue reading Bottled rockslide
Carly is a rock detective who hunts for evidence of ancient earthquakes around the world. She completed her PhD in Tromsø and a postdoc at McGill University in Montreal. In this article, Carly provides some background about earthquakes, and then goes on to tell us how she identifies ancient earthquakes in rocks. This tool is also applied to landslides. Next time you are hiking in the Norwegian mountains, you may just be stepping on signs of an old earthquake or landslide!
Like landslides, earthquakes are dangerous natural phenomenon that cause loss of human life and costly damage to infrastructure. And like coastal landslides, earthquakes can cause tsunamis, which compound the seriousness of their effects. Earthquakes can also trigger landslides and rockfalls when they happen in mountainous areas. Humans have been recording earthquakes for nearly 4000 years, and the deadliest earthquake in recorded history occurred in 1556 in Shaanxi, China where it is estimated that around 830 000 people died. The magnitude was around 8. The highest ever recorded magnitude for an earthquake was 9.5 for the 1960 Valdivia earthquake in Chile (Kanamori, 2006). There are several methods to measure earthquakes, and the most common scale used to estimate the magnitude of an earthquake today is the moment magnitude scale (MMS). The MMS measures shaking during an earthquake. The MMS replaces the outdated Richter scale, which cannot adequately measure earthquakes over magnitude 8. The MMS is a log scale, which means that at magnitude 9.5, the Valdivia earthquake shook around 32 times more than the magnitude 8 earthquake at Shaanxi. Norway’s most significant earthquake happened in 1904, in the Oslofjord area. It had a magnitude 5.4, and while there were no casualties, damage was caused to buildings. Continue reading Earthquakes: the landslides of the deep
Veslemannen, et ustabilt fjellparti i Romsdalen i Møre og Romsdal kommune, fikk mye oppmerksomhet i media mellom 2014 og 2019. «Hele» Norge fulgte nøye med på når fjellsiden skulle ramle. Beboerens i dalen nedenfor fjellet ble evakuert hele 16 ganger og Raumabanen ble stengt i perioder. I lys av en nylig publisert artikkel av Kristiansen et al. (2021) så tar vi en titt på Veslemannen. Hva skjedde med Veslemannen, og hvorfor er det så vanskelig å presist varsle skredet? Continue reading Hva var greia med Veslemannen?
About the geosite: Skredan is a spectacular landslide which sits above the village of Kaldsletta, 13 km south of Tromsø city centre on the mainland. It is a type of landslide termed a rock avalanche, meaning that a volume of rock collapsed and travelled in an avalanche train down the mountainside. We do not know a lot about this particular rock avalanche, for example when it occurred or if anyone was living there at the time. It is unlikely to have caused any damage as it did not reach the farms below, and based on other data sets could have occurred up to thousands of years ago. The hazard and risk posed by further rock avalanches from this area is currently under investigation. The avalanche is very prominent. It has a high and steep head wall/cliff at the top, and very prominent lobes of shattered rock debris sitting on the mountainside below. The avalanche has not traveled very far in comparison with other similar avalanches in the area. More geological information can be found in Andreas’ masters thesis (Norwegian). Continue reading Landslide geotourism series. Geosite 1: Skredan