PDF COPY - Manuel berberian

OF OMAN
Fig. 5. Map o£ documented seismically active faults of Iran.
The map show~ faults which are either observed on the surface and are known to have been
associated with earthquakes (Table I), or are lineaments in the selsmlclty that are not aasoelated
with aurface features (this applies only ~o the Zagros and they are thought to be faults in the
basement whleh tail to reach surface because o£ the salt tectonics; see Table II). Geometry of the
active faults and the meehaniam ot the large magnitude earthquakes along them clearly show that
the active tectonics of the region is dominated by ~rontal reverse faulting at the toot ot the
told-thrust mountain belts (Tables I, II and III). Predominant right-lateral reverse faulting
NW Iran indicates sideways motion ot blocks being pushed away Erom the Implnglng zone of the
Arabian plate with eastern Asia-Minor (NAF: North Anatolian fault, EAF: East Anatollan fault).
Deformation and seismlcity is spread out over a broad zone of the continent along several mountaln
bordering reverse faults and the continental crust is thlckening and shortening (vertical expansion)
In a NE-SW direction [Berberian 1976a, I979a]. Letters lndlcate entrlea In Table I. Only
selected fault plane solution are shown. The compressional axes deduced t~om the fault plane solutions
(Fig. q inset) often conform with the maximum horizontal shortening deduced ~rom the Neogene
axes ot the told systems [Berberian 1976a]. Many more faults than those documented and shown in
this £1gure must be active, therefore, this figure alone should not be used as a gulde to seismic
risk.
I. Doct~ented active faults associated with the known damaging or destructive earthquakes
(triangle tot thrust; short lines at rlght angle for hlgh-angle reverse fault; see also Table I).
4O
BERBERIAN