The coupling of a submarine slide and the surface waves which it generates

American Geophysical Union (AGU) - Tập 97 Số C8 - Trang 12731-12744 - 1992
Lin Jiang, Paul H. LeBlond

Tóm tắt

Underwater landslides are a common source of small‐scale tsunamis in coastal areas. They have been the object of only a few theoretical and experimental studies. A numerical model is developed to study the coupling of a submarine landslide and the surface waves which it generates. A formulation of the dynamics of the problem is presented, where the landslide is treated as the laminar flow of an incompressible viscous fluid and the water motion is assumed irrotational. Long‐wave approximation is adopted for both water waves and the mudslide. The resulting differential equations are solved by a finite‐difference method. We present the numerical results which contrast the behavior of the mud flow under a fixed surface, in the presence of one‐way coupling (bottom deformations affect the free surface), and with full coupling (surface pressure gradients react on the mud flow). It is found that three main waves are generated by a landslide starting from rest on a gentle uniform slope. The first wave is a crest which propagates away from the mudslide site into deeper water; this crest is followed by a trough in the form of a forced wave which propagates with the speed of the mudslide front. The third wave is a relatively small trough which propagates shoreward. Two major parameters dominate the interaction between the slide and the waves it produces: the density of sliding material and the depth of water at the mudslide site. The two‐way interactions are significant for the cases of a smaller mud density and shallower waters. For the cases of larger mud density and shallower waters, the two‐way interactions are small, but the waves generated are very large. For larger initiation depth of the mudslide, the interactions are weak and the waves generated are small. We also examined the possibility of a resonance between the slide and the waves. Our numerical results indicate that a resonance is not expected in many practical cases.

Từ khóa


Tài liệu tham khảo

De Matoes M. M. Mobility of soil and rock avalanches Ph.D. thesis Univ. of Alberta Edmonton 1988.

Edgers L. Viscous analysis of submarine flowsRep. 52207‐3 21Norw. Geotech. Inst. Oslo 1981.

Edgers L. K.Karlsrud Soil flows generated by submarine slides: Case studies and consequencesPublication 143 1–10Norw. Geotech. Inst. Oslo 1982.

Hamilton T. S., 1987, The foreslope hills of the Fraser River Delta: Implication of tsunamis in Georgia Strait, Sci. Tsunami Hazards, 5, 15

Johnson A. M., 1970, Physical Process in Geology

Karlsrud K., 1980, Marine Slides and Other Mass Movements, 61

Kirwan A. D., 1986, Time‐dependent hydrodynamic models of turbidity currents analyzed with data from the Grand Banks and Orleansville events, J. Sediment. Petrol., 56, 379

10.1111/j.1365-3091.1988.tb00905.x

10.1017/S0022112089002685

Locat J. J. P.Syvitski H.Norem A. E.Hay B.Long P. H.LeBlond C. T.Schafer G.Brugnot Une approche à l'étude de la dynamique des coulées sous‐marines: Le project ADFEX43e Conference Canadienne GeotechniqueCanadian Geotech. Soc.Quebec Canada 1990.

10.1029/JC092iC13p14581

10.1016/0040-1951(78)90212-3

Morgenstern N. R., 1967, Marine Geotechnique, 189

10.1029/JC084iC12p07777

10.1130/0091-7613(1985)13<538:SSATCO>2.0.CO;2

10.1061/(ASCE)0733-9410(1986)112:3(348)

10.1017/S0022112072002289

10.1029/TR036i005p00759

Thông tin
Thông tin xuất bản

American Geophysical Union (AGU)

Tập 97 Số C8

12731-12744

Thông tin tác giả