HR: 0800h
AN: NG51A-03    [Abstracts]
TI: Coupled seismic modes and earthquake hazard in Mexico City
AU: * Lomnitz, C
EM: cinna@prodigy.net.mx
AF: National University of Mexico UNAM, Institute of Geophysics, Mexico, DF 04510, Mexico
AB: Wave-to-wave coupling can arise when an acoustic pulse selects a Rayleigh mode of the same speed and both travel together swapping energy across an interface. A similar effect may cause severe damage at distances of several hundred kilometers when an Lg wavetrain incides upon a soft remote sedimentary waveguide, as in Mexico City. Energy at a single dominant frequency is then trapped in the waveguide. When the input power exceeds the damping losses, the trapped mode reverberates in the layer for up to five minutes, causing severe resonant damage to structures.
DE: 4410 Bifurcations and attractors
DE: 4435 Emergent phenomena
DE: 4455 Nonlinear waves, shock waves, solitons (0689, 2487, 3280, 3285, 4275, 6934, 7851, 7852)
DE: 4499 General or miscellaneous
SC: Nonlinear Geophysics [NG]
MN: 2007 Joint Assembly