The spatio-temporal rupture history of the September 2, 1992 Nicaragua tsunami earthquake (MS=7.2; MW=7.6) is analyzed using long-period (157-288 s) Rayleigh and Love wave spectral inversions and an empirical Green function analysis of very broadband (10-250 s) body and surface waves. The event has a rupture duration exceeding 110 s with a slow (0.6--2.3 km/s) rupture velocity, and involves shallow dipping (6¿--10¿) thrust faulting at a shallow depth (≤10 km), with the latter being primarily responsible for the strong tsunami excitation. Two subevents dominate the source radiation, resulting from a slow asymmetric bilateral, 100--160 km long rupture. Long-period surface wave directivity reveals a predominant rupture azimuth of 140¿¿30¿, consistent with asymmetric extension of the bilateral rupture at an azimuth of 125¿¿30¿ resolved by the source time function analysis. An inverse Radon transform of the source time functions confirms the asymmetric bilateral rupture characteristics. ¿ American Geophysical Union 1994