Lava Flows in Pico and Sao Jorge (September 2009)
On Pico Volcano four historical eruptions were recorded : Prainha (1562-64) from the rift ESE of Pico Volcano, and three fissure eruptions on the volcano's flanks: Santa Luzia (1718), Sao Joao (1718) and Silveira (1720). The first two produced vary large volumes of lava with flows about 10km long; the latter two were much smaller, with flows about 2km long and mean effusion rates of 0.5-1 cubic meters per second. A more recent fissure eruption occurred in 1808 on Sao Jorge Island. Note that historical lava flows are called «misterios» by locals.
Pico Volcano's summit (2351m.a.s.l.) rises above the inversion layer (view from Faial's Caldera).
The 100m tall cinder cone Piquinho stands within the summit crater of Pico (view from Sao Roque).
Cabecos do Misterio, steep spatter cones of the 1562-64 eruption on Pico Island.
Ponta do Misterio, the lava delta of the 1562-64 lava flows. Sao Jorge Island is in the background.
Pico Volcano rises from the morning fog (view from Madalena harbour, the NW tip of Pico).
A spectacular pressure ridge was pushed upwards by lava flows increasing below the solidified crust.
Ropy lavas on the side of the pressure ridge. Faial Island in the background.
The pressure ridge reaches the sea. These flows were erupted about 500-1000 years ago.
Plants start to colonize pahoehoe lava flows a few centuries old. Sao Jorge Island in the background.
Casts of trees which were enclosed by the lava flow and then carbonized. Roby gives the scale here.
Em Pè tuff cone, a Surtsey-like cone deeply eroded by wave action. Pico is in the background.
A skylight in front of the lava flow's entrance into the sea has resulted in this spectacular natural arch on Sao Jorge Island.
|Photos by Marco Fulle taken with 10-20mm, 24-85mm and 80-200mm lenses (reflex digicam with 16x24mm sensor).|