Abstract. Landslides triggered by strong earthquakes often
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caused most of the global damage and most of all casualties WQiRbb X
related to the events, such as shown by the M = 7.7 Peru 5/h-H r
earthquake in 1970, by the M = 7.6 El Salvador earthquake T{`V US/
in 2001 or by the M = 7.4 Khait (Tajikistan) earthquake j;z7T;!i
in 1949. The obvious impact of a landslide on the population OW@) 6
is directly related to its movement. Yet, prediction of ^EkxZ4*g
future failure potential and hence future risk to population 5jwv! L<n
is necessary in order to avoid further catastrophes and involves ~OvbMWu
the analyses of the origin of seismic instability. The H<<t^,E^.t
seismic landslide potential is mainly determined by the interaction UF }[%Sa
between the regional seismic hazard and local geological =2QP7W3mg<
conditions. At a local scale, seismic factors interfering fR {_P
with geological conditions can produce site-specific ground " Y^ 9g/
motions. The influence of such Site Effects on instability is %l a1-r~
the principal topic of this paper, which is divided into two 7[mfI?*m
parts, A and B. The present Part A is concerned with the correlation + TaxH ;
of field data with observed instability phenomena. 5k Q@]n:<k
Field data were obtained on mainly three landslide sites in G%>[7 ] H
the Northern Tien Shan Mountains in Kyrgyzstan, Central Wq5 }LO)
Asia. Geophysical prospecting, earthquake recordings, geological oJ3(7Sz
observation, trenching and geotechnical tests were + r;t]
the main investigation tools. The collected information gives tCGx ]\
an insight in the geological background of the slope failure CnZEBAU
and allows us to roughly infer failure mechanisms from field 3"v>y]$U
evidence. A detailed analysis of the susceptibility of a mechanism ']I!1>v$[
to specific geological conditions will be shown in Part o~\.jQQxa
B. lA1
1 Introduction
