Tectonic Plates and Faults - Earthquake Engineering for Structural Design - page 173

and Columbia, where some important strike-slip faults exist. The Western part is
due to the subduction of the Cocos plate under the Caribbean one.
South American segment is dominated by the fault resulting from the
subduction of the Nazca plate beneath the South American plate. The main
characteristic of this subduction is that the depth is shallow in the North and very
deep in the South (until 600 km). Due to this aspect, the earthquake influence
occurs over a wide boundary zone.
The following segments characterize the WesternPacific plateboundary :
Japanese segment . In the North and central parts, the Eastern part of Japan is
influenced by the Pacific plate subduction under the North American plate, while
the Western part by contact of the North American plate with the Eurasian plate. In
Southern Japan, the Philippine plate subducts the Eurasian plate.
Taiwanese segment . The Taiwan Island is located in the complex zone of
junction between the Eurasian and the Philippine plates. Contrary to the Japanese
coast, the Eurasian plate subducts beneath the Philippine plate.
Philippine and Guinea segments is due in the Northern part to the interaction
between the Indo-Australian and the Philippine plates, whereas in the Southern
part, to the interaction between the Pacific and the Indo-Australian plates.
New Zealand segment . New Zealand lies astride the junction of the Pacific (at
the East) and the Indo-Austalian (at the West) plates. The confluence of these
plates comprises several tectonic types. At the Northeast of the North Island, the
Pacific plate subducts the Indo-Australian plate. At the Southwest of the South
Island, the roles are reversed as the Indo-Australian plate subducts the Pacific
plate. These two different subduction zones are jointed by a transverse fault.
The Northern Pacific Plate boundary is characterized by the subduction of the
Pacific Plate under the North American Plate.
The Southern Pacific Plate boundary results from the contact with the Antarctic
Plate.
5.4.3 Alpide (Alpine)-Himalayan Belt
The Alpide (Alpine)-Himalayan belt (Fig. 5.28) is a mountain range, being, after
the Pacific Ring, the second for ground motion activities, but the largest and the
most varied one. Due to the fact that this belt is mainly continental, large areas
with diffuse faults characterize it. The extension is from the Mid-Atlantic Ridge to
the Pacific zone. About 5 to 6% of the world's earthquake energy and 17% of the
world's largest earthquakes have occurred along this belt. The first segment is
composed mainly by the Mediterranean area, resulting from the subduction of the
African plate beneath the Eurasian one. The Asian segment is due to the contact of
the Arabian and Indo-Australian plates against the same part of the Eurasian plate.