Abstract.New regional seismological data acquired in Colombia during 1993 to 1996 and tectonic field data from the Eastern Cordillera (

Summary A simple and unified approach is presented to solve both the elasto‐dynamic and elasto‐static problems of point sources in a multi‐layered half‐space by using the Thompson‐Haskell propagator matrix technique. It is shown that the apparent incompatibility between the two is associated with the degeneracy of the dynamic problem when ω= 0 and both can be handled uniformly using the Jordan canonical forms of matrices. We re‐derive the propagator matrices for both the dynamic and static cases. We then show that the dynamic propagator matrix and the solution converge to their static counterparts as ω→ 0. Satisfactory static deformation can be obtained numerically using the dynamic solution at near‐zero frequency.

Source parameter scaling for major and great thrust‐faulting events on circum‐Pacific megathrusts is examined using uniformly processed finite‐fault inversions and radiated energy estimates for 114 Mw ≥ 7.0 earthquakes. To address the limited resolution of source spatial extent and rupture expansion velocity (Vr) from teleseismic observations, the events are subdivided into either group 1 (18 events) having independent constraints on Vr from prior studies or group 2 (96 events) lacking independent Vr constraints. For group 2, finite‐fault inversions with Vr = 2.0, 2.5, and 3.0 km/s are performed. The product Vr3ΔσE, with stress drop ΔσE calculated for the slip distribution in the inverted finite‐fault models, is very stable for each event across the suite of models considered. It has little trend with Mw, although there is a baseline shift to low values for large tsunami earthquakes. Source centroid time (Tc) and duration (Td), measured from the finite‐fault moment rate functions vary systematically with the cube root of seismic moment (M0), independent of assumed Vr. There is no strong dependence on magnitude or Vr for moment‐scaled radiated energy (ER/M0) or apparent stress (σa). ΔσE averages ~4 MPa, with direct trade‐off between Vr and estimated stress drop but little dependence on Mw. Similar behavior is found for radiation efficiency (ηR). We use Vr3ΔσE and Tc/M01/3 to explore variation of stress drop, Vr and radiation efficiency, along with finite‐source geometrical factors. Radiation efficiency tends to decrease with average slip for these very large events, and fracture energy increases steadily with slip.