11. Above subduction zones, volcanoes exist in long chains called volcanic arcs . 12. The active volcanic arc creating supervolcano that today become Lake Toba in Sumatra. 13. The latter group is in one volcanic arc together with the Philippines volcanoes. 14. Some sediments were deposited near the Casma Volcanic Arc in an anoxic pockets. 15. Within this volcanic arc , volcanic activity provided pyroclastic ash fall deposits to the area. 16. El Chich�n is part of a geologic zone known as the Chiapanecan Volcanic Arc . 17. The field is located behind the main volcanic arc of the Central Volcanic Zone. 18. During the Pliocene the SVZ south of 38�S consisted of a broad volcanic arc . 19. It is tectonically influenced by the Arabian Plate Taftan form the Sultan volcanic arc . 20. The forearc lies between the trench and the volcanic arc .
