Temporary broadband seismic observations have been carrying out at the Baikal Rift Zone (BRZ), Russia, from January 2004 in order to study the lithospheric structure and evolution of Siberian Craton - Baikal Rift Zone – Mongolia Okhotsk mobile belt. The observations have been conducting by the cooperative program between Institutes of Siberian Branch, Russian Academy of Science (RAS) and the National Institute of Polar Research (NIPR); they will continue until the end of 2005. The observation system consists of a broadband seismometer (CMG-40T), with continuous recording by 24-bit A/D data-logger (LS8000-WD). The station was installed at Maksimikxa (MXM), where located at the center of southern coast of Lake Baikal, with maintained by RAS staff.

The BRZ is considered to have formed lastly in Cenozoic ages by both active and passive origins. Crustal extension associated with the regional phenomena underlying mantle plumes is suggested as the active origin. On the contrary, extension related with the India - Eurasia collision is demonstrated as the passive source. A formation scheme of the BRZ, moreover, is controlled by three factors: i.e., 1) mantle plumes, 2) older (pre-rift) linear lithosphere structures positioned relative to the plumes, and 3) favorable orientation of far-field forces (Zorin, et al., 2003). Crustal thickness beneath BRZ was obtained as more than 50 km from the deep seismic surveys (Suvorov et al., 2002). This evidence is almost opposite feature in the thin-skinned tectonics to form generally understood rift zones. Why these characteristic features of the think crust created? This thick crust at BRZ is also supported by the combined interpretation for the crustal section derived from both geophysical and geological information (Zorin et al., 2002). Several big sutures and large pre-Cenozoic thrusts are supposed to exist associated with the past collision tectonics between Siberian Platform and Mongolia-North China continent.

Regarding these tectonic information from previous studies, several scientific targets are proposed by using broadband seismic data at BRZ. By utilizing the teleseismic waveforms, velocity structure in the crust and the uppermost mantle is expected from the analysis of receiver functions and shear wave splitting, etc. Additionally, the obtained data have a usage for the RAS studies, such as hypocentral determination and detection of seismicity for the local events, together with a construction of a precise regional velocity model.