Faults and Earthquakes - Earthquake Engineering for Structural Design - page 207

(Boudreau, 2001). In comparison with shallow ruptures, the process is very slow,
the velocity being less than half of the one for shallow rupture.
The most important seismic zones, where intraslab earthquakes occur, are:
Aleutian-Alaskan and Cascadia in North America; Hokkaido, Mariana and
Sumatra in West Pacific; Mexico in Central America; Peru and Chile in South
America. The large shallow intraslab earthquakes produced along the Circum-
Pacific Ring are presented in the Figure 6.26, both in North and South American
and in Western and South Pacific regions (Seno and Yoshida, 2004).
In Europe, the most known intraslab earthquakes are the Vrancea (located at
the sharp bend of the South Eastern Carpathian Mountains) and the Hellenic Arc
(in the South of Greece, formed as the result of the convergence between the
Aegean microplate and the African Plate) (Benetatos and Kiratzi, 2004) (Fig.
6.27). Vrancea earthquakes occur in a site of very special features, which can be
considered as being unique in the world (Wenzel et al, 2002) (Fig. 6.29a). This
region is situated in the Eastern Carpathian Arc bent area, being produced by the
subduction of the Black Sea microplate beneath the Intra-Alpine block (which
belongs to the West Eurasian Plate) (Balan et al, 1982, Pustovitenko et al, 1994,
Stiopol et al, 1994, Bala et al, 2003, Sandi, 2004, Knapp et al, 2006, Ciucu and
Fulga, 2008). The particularity of this intraslab region consists in a very small and
practically vertical mantle volume 30x70x130 km (Fig. 6.29b), where earthquakes
Vrancea
earthquakes
Helenic arc
earthquakes
Figure 6.28 European intraslabe earthquakes: Vrancea and Hellenic Arc
(after Benetatos and Kiratzi, 2004)