Km Of Path Research Articles

Coseismic and monsoon-triggered landslide impacts on remote trekking infrastructure, Langtang Valley, Nepal

In 2015, the M w 7.8 Gorkha earthquake struck Nepal, triggering thousands of landslides across the central and eastern Himalayas. These landslides had many adverse effects, including causing widespread damage to low-grade transport routes (e.g. tracks, footpaths) in rural regions that depend on tourism for survival. Langtang Valley is a glacial–periglacial landscape located 60 km north of Kathmandu. It is one of the most popular trekking regions in Nepal and has been severely affected by Gorkha earthquake-triggered and monsoon-triggered landsliding. Here, qualitative and quantitative observations from fieldwork and remote sensing are used to describe the materials and geomorphology of the landslides across Langtang Valley, and to quantify the extent to which coseismic and monsoon-triggered landslides have affected Langtang's trekking infrastructure. The dominant bedrock materials involved within Langtang landslides are found to be a range of gneisses and intruded leucogranites. In total, 64 landslides are found to have intersected trekking paths across Langtang, with coseismic and monsoon-triggered landslides having an impact on c. 3 km and 0.8 km of path respectively. It is observed that the practice of reconstructing paths through unstable landslide deposits is leaving the trekking infrastructure across Langtang increasingly vulnerable to future failure.

Exposure-based risk assessment and emergency management associated with the fallout of large clasts at Mount Etna

Abstract. Fallout of ballistic blocks and bombs ejected from eruptive vents represents a well-known hazard in areas proximal to volcanoes (mostly <5 km from the vent). However, fallout of large clasts sedimenting from plume margins that extend to medial areas and have the potential to produce severe injuries to people and cause damage to infrastructure, is often overlooked. Recent eruptive events at Mount Etna (Italy) provide a clear example where large-clast fallout from plume margins (>5 cm) has posed a real threat both to the many visitors reaching the summit area and to local infrastructure, and, therefore, has been selected as a case study. To quantify this hazard, a new particle sedimentation model was calibrated with field data and then used for probabilistic hazard assessments. For a fully probabilistic scenario the hazard zone covered 72 km2 and included some 125 km of paths and roads, as well as 15 buildings. Evacuation on foot to a safe area was estimated at almost 4 h, but this could be reduced to less than 3 h if two shelters were provided. Our results show the importance of integrating probabilistic hazard analysis of large-clast fallout within effective strategies of risk management and reduction, especially in the case of volcanoes where visitors can reach the summit areas.

Scraping marking behaviour of the largest Neotropical felids.

BackgroundDetails of how, why and in what conditions large felids make scrapes is unknown. Here, we examined the general hypothesis about the use of scrapes for marking proposals, as well as to communicate with other individuals to signalize particular points or areas of interest, by studying scrape-marking behaviour of jaguars and pumas.MethodsWe surveyed by scrapes between five days and two months mainly during dry season in five study areas from Mexico (El Edén and San Ignacio), Belize (Cockscomb) and Brazil (Angatuba and Serra das Almas), which differed in presence and/or abundance of jaguars and pumas. Paths were slowly walked while searching for scrapes by teams normally composed of two people and tracks were stored in GPS, distinguishing the type of path surveyed (unpaved track roads, trails and cross-country).ResultsWe found a total of 269 felid scrapes along 467 km of paths surveyed, obtaining a finding rate of 0.576 scrapes per km. Most scrapes were found in car tracks (0.629 scrapes per km), followed by trails (0.581 scrapes per km), and rarely did we find scrapes in cross country (0.094 scrapes per km). In trails, scrapes were found in a similar frequency in the centre and edge, whereas in car tracks they were mainly found in the edge. There were also clear differences in the position of the scrapes between study areas that differed in presence and/or abundance of pumas and jaguars, with scrapes located mainly in the centre in areas only with pumas, in the centre and in the edge in areas with a similar number of jaguars and pumas, and in the edge in area mainly dominated by jaguars. The remarking rate tended to be higher in one of the areas with only pumas where natural vegetation was scarcer. Felids chose sites mainly covered by leaves and located in paths less wide, clean and rarely used.DiscussionScraping was a frequent behaviour in the largest felids of America, although in some areas, scraping behaviour was rare. Scrapes seem to be signalizing some specific areas within territories and data suggest that they are made with the proposal of communication between individuals. It seems that a high scraping behaviour in pumas is not related to the presence of jaguars.

Geo-hiking map of Mt. Penna and Mt. Aiona area (Aveto Natural Park, Italy)

This work presents a geo-hiking map of Mt. Penna and Mt. Aiona area (Aveto Natural Park, Italy), an original and useful tool in the Earth science mapping field. Aveto Park is one of the best known Italian protected areas; it is located in the Ligurian Apennines and belongs to the Ophiolitic Protected Areas Coordination (‘C.A.P.O.’) and to the European Ecological Network Nature 2000. The Park area is crossed by more than 500 km of paths and trails where hikers, climbers and mountain lovers walk every year. The geo-hiking map was compiled by combining available geological and geomorphological bibliographic data with a field survey and basic information derived from hiking and tourist maps. The main stages used for production of the map are as follows: (a) bibliographic and map research of scientific papers; (b) a geological and geomorphological field survey; (c) trail and route data from tourist park maps; (d) research of geotouristic elements of interest. This work shows an example of geocartography research that really contributes to the implementations of documents and maps useful in the hiking tourism field. The main map is complemented with a natural hazard map; increasing tourism during the whole year in areas with geomorphological hazards results in a relationship between the human element, natural processes and hazard phenomena.

Air-Coupled Seismic Waves at Long Range from Apollo Launchings

Microphones and seismographs were co-located in arrays on Skidaway Island, Georgia, for the launchings of Apollo 13 and 14, 374 km to the south. Simultaneous acoustic and seismic waves were recorded for both events at times appropriate to the arrival of the acoustic waves from the source. The acoustic signal is relatively broadband compared to the nearly monochromatic seismic signal; the seismic signal is much more continuous than the more pulse-like acoustic signal; ground loading from the pressure variations of the acoustic waves is shown to be too small to account for the seismic waves; and the measured phase velocities of both acoustic and seismic waves across the local instrument arrays differ by less than 6 per cent and possibly 3 per cent if experimental error is included. It is concluded that the seismic waves are generated by resonant coupling to the acoustic waves along some 10 km of path on Skidaway Island.