Cutremure "lente", ce sunt si cum se manifesta ?

[GeoX1]

In ultima vreme, gasim destul de frecvent referiri pe net la asa-numitele cutremure lente, in care de fapt nu se propaga unde seismice (de tip elastic), ci sunt niste procese geotectonice care "simuleaza" cumva fenomene generatoare ale cutremurelor, dar manifestate silentios.

Pentru inceput, iata un material legat de San Andreas:

Material primit pe mail de la grupul de discutie californiadisasters (Yahoo Groups).

 

[real321]

Da, majoritatea cutremurelor crustale se produc in stratul seismogen, uzual pana la adancimi de 15 km, unde predomina mecanismul de rupere fragila. Sub stratul seismogen incepe sa predomine mecanismul ductil si se produc astfel deplasari aseismice.

Wikipedia

The seismogenic layer is the range of depths within the crust or lithosphere over which most earthquakes are initiated.[1] Typically in continental crust this is in the uppermost 15 km.[2] The base of this layer represents the downwards change in deformation mechanism from elastic and frictional processes associated with brittle faulting to a generally aseismic zone where ductile creep becomes the dominant process. The location of this change in deformation style is sometimes referred to as the Brittle-ductile transition zone

Zona de tranzitie fragil-ductil:

Este interesant ca uneori tensiunile se pot propaga si aseismic.

 

[r3lu84]

Un documentar foarte interesant chiar pe aceasta tema: Slow Earthquakes and Mega Earthquakes in Japan