The Pico-Faial ridge is a steep WNW-ESE volcanic ridge that has developed within the Nubia-Eurasia diffuse plate boundary, close to the Azores Triple Junction. The ridge comprises two islands, Pico and Faial, separated by a shallow (<100 m depth) and narrow (<8 km) channel. Despite some similarities, the two islands show contrasting features still deserving explanation: (1) meaning of GPS data; (2) meaning of palaeomagnetic data; (3) the island-scale Faial Graben does not have a counterpart in Pico; (4) both islands comprise a main central volcano each, but the one in Faial is symmetrical and the one in Pico is asymmetrical; (5) Pico shows evidence of at least two large-scale flank collapses, but none has been recognized so far in Faial. The new data reported here lead to the following probable answers: (1) the GPS data show much larger vertical and horizontal ground motions in Faial, which could be the result of recent volcanism and tectonics; (2) the cyclicity inferred from the paleomagnetic data in Pico could be related to inflation/deflation cycles that could have triggered the inferred flank collapses; (3) the Faial Graben ends abruptly at the eastern edge of the island, which we interpret as inhibited propagation to the east because of the load and stresses imposed by the nearby large Pico Volcano; (4) we attribute the asymmetry of the Pico Volcano to partial flank collapse recognizable in new offshore seismic profiles; (5) either the Faial island is actually gravitationally more stable, or there have been flank collapses not yet recognized. All these processes have concurred to shape the two islands and the ridge to their current morphology, but the current morphologies of Pico and Faial result mainly from three of these processes: volcanism, tectonics and large-scale landslides.

Pico-Faial山脊是一条陡峭的WNW-ESE火山山脊，在Nubia-Eurasia扩散板边界内靠近亚速尔群岛三重交界处发育。该山脊包括两个岛，皮科岛和法亚尔岛，由浅（<100 m深度）和窄（<8 km）的河道隔开。尽管有一些相似之处，但两个岛屿仍具有鲜明的对比特征，仍然值得解释：（1）GPS数据的含义；（2）古地磁数据的含义；（3）岛屿规模的Faial Graben在Pico中没有对应对象；（4）两个岛各有一个主要的中央火山，但Faial中的一个是对称的，而Pico中的一个是不对称的；（5）笔克显示出至少两次大规模的侧面崩塌的证据，但迄今为止在Faial中都没有发现。此处报告的新数据导致以下可能的答案：（1）GPS数据显示Faial的垂直和水平地面运动要大得多，这可能是最近火山作用和构造的结果；（2）从皮克古地磁数据推断出的周期性可能与可能触发推断的侧倾崩溃的充气/放气周期有关；（3）Faial Graben突然终止于该岛的东部边缘，我们将其解释为由于附近大型笔克火山施加的负载和应力而阻止了向东部的传播；（4）我们将皮科火山的不对称性归因于在新近海地震剖面中可以识别出的侧翼部分塌陷；（5）Faial岛实际上在重力上更稳定，或者有侧面崩塌尚未被识别。