This paper investigates the concept of frequency and magnitude firstly in the context of a range of important, frequently studied weathering processes (e.g. solution, fire, thermoclasty, haloclasty, frost, and biological weathering
) and their effectiveness in terms of rock breakdown, and secondly in terms of the totality of weathering and its effectiveness in terms of larger-scale geomorphological change.Finally, the importance of the ideas of frequency and magnitude as applied to weathering
Evaluating the occurence of low magnitude floods: a study of the reliability of the annual maximum series method
In this paper frequency distributions of low magnitude floods derived either from annual maxima (AMS) or from all peaks exceeding a selected threshold discharge are compared for ten gauging stations from the upper Vistula River drainage basin
. A considerable variation in the mutual relation of the two series exists for the stations despite their close proximity, and this seriously questions the utility of the AMS approach for reliable evaluation of the magnitude-frequency relationship for low magnitude
The parameters of frequency and magnitude and their relationship provide only a partial explanation of episodic process behaviour. Full characterization of episodic processes from a geomorphic perspective should include, initiating and ending
Tsunami magnitudes in Taiwan, the Philippines and Indonesia
Tsunami magnitudes on the Imamura-Lida scale are investigated by the author's method (Hatori 1979, 1986) using the data of inundation heights near the source area and tide-gauge records observed in Japan. The regional characteristic of tsunami
magnitudes is discussed in relation to earthquake magnitudes during the period from 1960 to 1994.
Frequency and magnitude of landsliding : fundamental research issues
Magnitude and frequency in geomorphology
Concept ; Distribution spatiale ; Fréquence et magnitude ; Glissement de terrain ; Modélisation ; Méthodologie ; North Island ; Nouvelle-Zélande ; Précipitation ; Risque naturel ; Statistique ; Versant
Some fundamental research issues related to the application of frequency-magnitude analysis to landslides are discussed. It is shown that there are marked differences between the hillslope system and the fluvial system. Methodological approaches
to the establishment of temporal and magnitude frequency are presented and illustrated. Both empirical and deterministic methods are discussed. In particular, advances in empirical modelling are used to show the extent to which the probability of landslide occurrence
can be determined with a regional context. Frequency-magnitude analysis can also be applied to the spatial distribution of landslides.
Sediment production, storage and output : the relative role of large magnitude events in steepland catchments
Magnitude and frequency in geomorphology
Bassin-versant ; Bilan d'érosion ; Charge en suspension ; Erosion des berges ; Erosion des sols ; Fréquence et magnitude ; North Island ; Nouvelle-Zélande ; Pente de versant ; Ravinement ; Utilisation du sol ; Végétation
Magnitude-frequency analysis provides an approach to assess the effectiveness of rare events for generating and transporting sediment in the 32 km2 Tutira catchment and the 2205 km2 Waipaoa River Basin, located in the erodible softrock hill country
of the eastern portion of New Zealand's North Island. Shallow landsliding, triggered by high-intensity storms, is an important erosion process throughout the region. The long-term record of sedimentation in Lake Tutira suggests that the magnitude and frequency
Frequency-magnitude distributions for soil erosion, runoff and rainfall - a comparative analysis
Magnitude and frequency in geomorphology
Belgique ; Bilan d'érosion ; Canada ; Concept ; Erosion des sols ; Etats-Unis ; Fréquence et magnitude ; Précipitation ; Royaume-Uni ; Ruissellement ; Régression linéaire ; Versant
This study analyses frequency-magnitude distributions of rainfall, runoff and erosion from sites in the UK, Belgium, Canada and the USA. Frequency-magnitude distributions of rainfall appear to be a poor predictor of distributions of runoff or soil
Simulation of slope development and the magnitude and frequency of overland flow erosion in an abandoned hydraulic gold mine in Models in geomorphology.
Construction and use of a numerical simulation model of hillslope development to assess the contribution of various runoff magnitudes to soil erosion and the long-term development of hillslopes in northern California.
Frequency and magnitude of bedload transport in a mountain river
Magnitude and frequency of bedload transport was examined in the Lainbach River, Bavaria, using magnetically tagged particles in the summers of 1988 to 1992, during which 18 small to moderate events and one major event occurred. These data present
an opportunity to study the relation between the frequency and magnitude of sediment transport and major channel-forming events.
The magnitude-frequency concept in fluvial geomorphology : a component of a degenerating research programme?
Magnitude and frequency in geomorphology
Capacité de charge ; Concept ; Débit ; England ; Erosion des berges ; Fluviatile ; Fréquence et magnitude ; Géométrie hydraulique ; Méandre ; Programme de recherche ; Royaume-Uni ; Transport sédimentaire
This paper presents a critique of that magnitude-frequency concept which defines an effective, or dominant event in terms of long-term sediment transport, and then associates this with channel morphology. A more appropriate geomorphological research
Representing the landslide magnitude-frequency relation : Capilano river basin, British Columbia
The AA. use magnitude-frequency analysis as a statistical tool to quantify the erosion caused by landslides and debris flows. Using air-photo- and ground-derived data they show that the departure from power-law distribution customarily observed
for small magnitude is an artefact of sampling deficiencies. Nonetheless, the total distribution is not sensitive to the frequency of small slides and total erosion remains adequately represented in the air-photo-derived data. Their data also demonstrate
a real departure from simple scaling at much larger magnitudes, the cause of which is not definitively established.
Estimation of debris-flow magnitude in the Eastern Italian Alps
Data on debris-flow magnitude from 127 basins in the Eastern Italian Alps have been collected from scientific and technical journals, technical reports, historical reports gathered from local archives, and field surveys. These data were used
to develop and test different predictive approaches, encompassing regression equations, geomorphological surveys and probabilistic analysis of time series. Regression techniques were used to correlate debris-flow magnitude to morphometric parameters
and geological characteristics of the basins. The combined use of different approaches for the estimation of debris-flow magnitude is suggested.
The relative geomorphic work effected by four processes in rainstorms: a conceptual approach to magnitude and frequency
This paper first proposes a probabilistic approach of the relationship between rainfall amounts and degree of landsliding (Gallart, 1990) and then to apply it to a modification of the quantitative magnitude-frequency approach suggested by Wolman
On the ages and magnitude of debris flows in the Polish Tatra mountains
Detailed geomorphological mapping, supplemented by lichenometric datings and lacustrine sediment studies, shows that debris flow activity on the high-mountain Tatra slopes/South Poland/increased in both frequency and occurrence as well as magnitude
This paper discusses the effects of storm intensity on the magnitudes of slope failure and sediment yields in Japan. Data were analyzed for 813 river basins that experienced storm-induced failure as well as 30 basins with sediment yield data
. The basins were grouped into 3 categories according to storm intensity to examine the relation between rainfall and erosion magnitudes. Slope-failure magnitudes and sediment yields are also affected by hillslope inclination. The effect of hillslope
Hillslope erosion by rainstorms. A magnitude-frequency analysis
Daily rainfall data for four stations in Europe and east Africa are used to obtain, by means of magnitude-frequency analysis, a measure of Cumulative Erosion Potential (CEP) that takes into account rainfall characteristics, soil water storage