Size-Frequency Relationship of Submarine Landslides at Convergent Plate Margins: Implications for Hazard and Risk Assessment
We use complete inventories of submarine landslides from the Middle America (MA) and the Central Chile (CC) trench and forearc systems to analyze the size-frequency relationship of such structures on active continental slopes. The MA forearc is characterized by subduction erosion, and the CC forearc has had an accretionary tectonic history since the Late Neogene. Both are end-member types of convergent margins around the world. Both margin segments have been mapped by high-resolution swath bathymetry at strike lengths of about 1,300 km (MA) and 1,000 km (CC). The Middle America forearc has 143 discernible slides with sizes ranging from 0.38 to 1,426 km2. Offshore Central Chile, the 62 mapped slides are 0.9–1,285 km2 in size. Slide localization is markedly different at both margin types. While they also vary strongly along strike of the individual margin, depending on forearc slope gradient, kinematic coupling between plates, or topographic structure of the downgoing plate, the size-frequency relationships are remarkably similar. This allows quantification of the incidence of a submarine slide of given size per margin segment. The relationships hold for slide sizes from 10 to 1,000 km2, with the cut-off defined by slide size (smaller slides) and sample size (larger slides). As slide traces of 100–300 km2 size are obliterated by tectonic deformation after about 200,000 years, recurrence rates for slides of a given size can be estimated. This offers a chance to assess hazard and risk resulting from such events. It is suggested that it takes 20 to 200 plate boundary earthquakes to set off a medium-sized (>10 km2) or larger slump or slide.
KeywordsConvergent plate boundary Tectonics Erosion Accretion Submarine landslide Chile Central America
We are grateful for the reviews of this manuscript by Yuzuru Yamamoto and Achim Kopf, which helped to improve the original manuscript.
- Anasetti A, Krastel S, Weinrebe W et al (2010) Detailed analysis of the Valdes Slide: a landward facing slope failure off Chile. Abstract EGU2010-13497, 2010 General Assembly of the EGU, Vienna, 2–7 May 2010Google Scholar
- Harders R, Ranero CR, Weinrebe W et al (2012) An overview of the role of long-term tectonics and incoming plate structure on segmentation of submarine mass wasting phenomena along the Middle America Trench. In: Yamada Y, Kawamura K, Ikehara K (eds) Submarine mass movements and their consequences. Springer, Dordrecht/Heidelberg/London/New York, pp 391–402. doi: 10.1007/978-94-007-2162-1 CrossRefGoogle Scholar
- Kimura G, Silver E, Blum P et al (1997) Proceedings of the ocean drilling program, Initial reports, 170. Ocean Drilling Program, College Station, 458 ppGoogle Scholar
- Kukowski N, Oncken O (2006) Subduction erosion – the “normal” mode of fore-arc material transfer along the Chilean Margin? In: Oncken O, Chong G, Franz G et al (eds) The Andes – active subduction orogeny. Springer, Berlin, pp 217–236Google Scholar
- Mulder T, Cochonat P (1996) Classification of offshore mass movements. J Sediment Res 66:43–57Google Scholar
- Völker D, Wiedicke M, Ladage S et al (2006) Latitudinal variation in sedimentary processes in the Peru-Chile Trench off Central Chile. In: Oncken O, Chong G, Franz G et al (eds) The Andes – active subduction orogeny. Springer, Berlin, pp 193–216Google Scholar
- Völker D, Geersen J, Behrmann JH et al (2012) Submarine mass wasting off Southern Central Chile: distribution and possible mechanisms of slope failure at an active continental margin. In: Yamada Y, Kawamura K, Ikehara K, Ogawa Y, Urgeles R, Mosher D, Chaytor J, Strasser M (eds) Submarine mass movements and their consequences. Springer, Dordrecht/Heidelberg/London/New York, pp 379–389. doi: 10.1007/978-94-007-2162-3_34 CrossRefGoogle Scholar