IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS011 Poster presentation 2169
The analysis of the strained state of main seismotectonic zones of Menian
upland
Dr. Eduard Gyodakyan
JSS011 Poster Presentation IASPEI
Naira Geodakyan
The spatial distribution sources of earthquakes of Armenian highland specifies on the naturally located
linear structures of sources of earthquakes well correlating with tectonic zones of disturbances. The
strong earthquakes are confined to areas of intersection of the longitudinal and cross folding and to
Anatolian and Zagross fault zones. For definition of the strained state of main seismotectonic zones the
data of mechanisms of the sources more than 185 earthquakes with М> = 4 are involved. The analysis
of the parameters of sours mechanisms specifies, that the majority of planes of rupture have dip at an
angle α=450, that is the earthquakes with abrupt planes of rupture dip prevail, characteristic at
movements in sources of earthquakes, corresponding to throw and upthrow depending on orientation of
axes of compression and tension strains. Precise conformity of a direction of one of planes of the break
with directions of seismic hazardous zones is revealed. The data on directions of compression axes
show, that almost on all seismotectonic zones the axes of compression having a nearhorizontal
directions prevail, except for the zone of extend from Erzinjan to Northeast. Earthquakes with
compression axis which make an angle more than 300 with a horizon here are observed. On all main
seismotectonic zones prevailed directions of tension axes placed by some corners, except for seismic
active zones of Javakhet highland and southern part of Transcoucasus zone, where tension axes
orientations are nearer to a perpendicular direction. The dominant types of motions characteristic for
separate sites of researched area are revealed. The northeast part Armenian highland is characterized
by the up throw-thrust motions and the area between Taur and Anatolia - mainly by faults with the
elements of left lateral slip. Earthquakes near the Lake Van characterized with down slips and in
northern part of the motions of up throw type prevail. The analysis of the strained state of the region as
a whole specifies on dominant strains of compression in a horizontal plane in a direction 150-200
northeast and on tension strain in a vertical plane 300-600.
Keywords: highlandstraineddirection