The Ilan basin related to Okinawa Trough is a extension environment dominated by normal faults and the collision zone is still a compressive environment because of the arc-continental collision.

• 在前人的研究中，多半将此区的宜兰平原与纵谷地区分开讨论，认为宜兰平原受最新期海槽张裂活动的影响正处于伸张环境，地震多为正断层；