Stretching out from the dormant volcano, with an altitude of 7715 feet (2351 m), which gives it its name, the island of Pico (Peak) has an oblong shape, a length of 26 miles (42 km), a width of 9 miles (15.2 km), and a total area of 173 sq miles (447 km2). A plateau with secondary volcanic cones ends next to the sea in tall cliffs while the lowest area in the west has moderate slopes. Pico is one of the “triangulo” (triangle) islands which also include Faial and S. Jorge.
Generally, the island of Pico’s tectonic structures are oriented along a west-northwest to east-southeast and a northeast to southwest axis. The main axis controls the main structures, especially the main mountain of Pico, while the secondary axis affect the radial fractures and faults along the central plain and eastern volcano.
Pico, much like the other islands, is susceptible to seismic events though the epicenters of these events have primarily been localized in the Faial-Pico or Pico-Sao Jorge Channels. The strongest earthquake registered in the last 30 years occurred on July 9, 1998, and had its epicenter 5 kilometers northeast of “Ponta da Ribeirinha”, on the island of Faial, reaching a 6.0 magnitude. Other earthquakes which have affected the island include: the 1957-58 seismic events associated with the eruption of the “Capelinhos” volcano on Faial, the February 1964 earthquake on the island of Sao Jorge, and the 1926 earthquake, whose epicenter was registered in the Faial-Pico Channel.