HR: 14:10h
AN: GP43C-03 INVITED     [Abstracts]
TI: The Seismicity and Crustal Structure of Continental Eastern Russia
AU: * Mackey, K G
EM: mackeyke@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824-1115 United States
AU: Nichols, M L
EM: nicho199@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824-1115 United States
AU: Fujita, K
EM: fujita@msu.edu
AF: Michigan State University, Department of Geological Sciences, East Lansing, MI 48824-1115 United States
AU: Gounbina, L V
EM: glv@emsd.magadan.ru
AF: Magadan Experimental Methodological Seismological Division, Skuridina 6b, Magadan, 685024 Russian Federation
AU: Koz'min, B M
EM: b.m.kozmin@diamond.ysn.ru
AF: Institute of Diamonds and Precious Metal Geology, Russian Academy of Sciences, 39 Lenin Prospekt, Sakha Republic (Yakutia), Yakutsk, 677892 Russian Federation
AB: Regional networks were established under the Former Soviet Union to monitor seismic activity and evaluate seismic hazards. In eastern Russia, these networks were deployed starting in the early 1960s. The networks generally operated analog short-period instruments, with some base stations having long-period sensors. Approximately 50,000 events have been located on the continental part of eastern Russia. These earthquakes define the boundaries between three major (Pacific, North America, Eurasia), and several minor (Bering, Okhotsk, Amur, Primoria) plates. The zones of seismic activity are diffuse and indicate that deformation between these plates is distributed over a large number of faults. Major strike-slip faults can be identified both by linear trends in the larger seismicity and in satellite imagery; examples include the Ulakhan fault system, between North America and Okhotsk, the Ketanda fault system between Okhotsk and Eurasia, and a system of faults in southern Yakutia and the Stanovoi Range between Eurasia and Amur. Regional arrivals at Russian seismic stations were used to determine crustal P- and S-wave velocities. A grid search method conducted along a moving window through eastern Russia to find best-fit velocities for minimizing travel-time residuals yields a model that is consistent with the tectonic setting (cratons, rift zones). Preliminary ground-truth experiments in the Magadan district show a good fit between the determined best-fit velocities and those from industrial explosions, as do those from previous Russian seismic surveys. Earthquake relocations using these best-fit velocities, and combining data from between networks, reveal linear trends and clusters which can be associated with active faults. Considerable contamination of the Russian seismicity catalog by industrial explosions has also occurred.
DE: 9320 Asia
DE: 7230 Seismicity and seismotectonics
DE: 8107 Continental neotectonics
DE: 8158 Plate motions--present and recent (3040)
DE: 7205 Continental crust (1242)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting