Abstract: The May 12, Ms 8.0 Wenchuan earthquake is tectonically due to the convergence of the India plate against the Eurasia plate at a rate of ~50 mm/yr, which resulted in the crustal movement toward the eastern Sichuan Basin and the southeastern China continent from the uplifted Tibetan Plateau. The epicentral area is located in the active Longmenshan centralized seismic zone along which the aftershocks are concentrated within a ~350 km long and ~100 km wide active belt of horizontal projection.Hypocentral depths range generally from ~10 to ~20 km within the crustal seismogenic zone above the brittle-ductile transition boundary, characterized typically by shallow tectonic earthquakes. Focal mechanism of the Wenchuan earthquake bears a close correlation with the Longmenshan tectonic movement indicated by the particular deep structural anomalies of the rapid crustal transition deepened westward, gravity gradient, high Vp/Vs ratio of average 2.2, and geological features of thrust faulting style with strike slip history. Response spectra for rock and soil sites are, respectively, estimated and compared for different tectonic regimes, based on the study of source, path and site effects, emphasizing soil site amplification effect. Also studied are safety concerned issues for prevention of future damaging earthquakes including geological hazards, seismic design, earthquake early warning systems (EEWS), and strategies of long term to short term earthquake forecasting. A sample of design spectra is presented on weighted average rock-site attenuation models. Topic on seismotectonics and earthquake dynamics in the areas of high seismic risk could be well incorporated with engineering geology and environmental engineering. Study on performances of the newly designed and constructed engineering structures should provide most valuable input to improving seismic design codes in China and throughout the world. It is a challenging task to predict earthquakes; however, effort should never be given up. Earthquake disaster reduction and prevention is a realistic measure for safeguard of future damaging earthquakes.