Latent tsunamigenic risk by a submarine landslide at

Guagua Pichincha
Cerro Azul, Galapagos
Volcanología & Geología
Universidad San Francisco de Quito
ECUADOR 2007
Clases, Salidas y Experimentos Analogicos
Revisiting the Avenue of the Volcanoes
200th Anniversary since the first visit of Alexander von Humboldt in Ecuador
Tungurahua
El Altar
Latent tsunamigenic risk by a submarine
landslide at unstable flanks of the
volcano Roca Redonda, Galapagos
with implications for major Ecuadorian harbors
ITSU, Guayaquil, 15.09.2007
Theofilos Toulkeridis1, Marcelo Cando1,2,3, Giorgio de la Torre4
1Centro
de Geología, Volcanología y Geodinámica, Universidad San Francisco de Quito, Quito,
Ecuador
2Direccion Nacional de Protección Ambiental (DINAPA), Ministerio de Energía y Minas, Quito,
Ecuador
3Facultad de Ciencias, Departamento de Química Agricola, Geología y Geoquímica, Universidad
Autonoma de Madrid, Madrid, España
4Instituto Oceanográfico de la Armada (INOCAR), Guayaquil, Ecuador
Megatsunami
(iminami or “wave of purification”)
Landslide-generated tsunami:
•Submarine landslides create “surprise tsunamis” from small
or distant earthquakes
•Surprise tsunami can initiate far outside of the epicentral
area of an associated earthquake.
•Surprise tsunami can be far larger than expected given the
earthquake size.
Megatsunami
(iminami or “wave of purification”)
Landslide-generated tsunami:
•The geography of earthquakes only casually resembles the
geography of submarine landslides.
•Tsunami excitation mechanisms between earthquakes and
landslides differ substantially.
•Surprise tsunami may arrive without any precursory seismic
warning at all (a tsunami sprung from a spontaneous
submarine landslide)
Past Case Examples:
New Guinea's north coast in 1998 Tsunami
Lituya Bay in Alaska on the night of July 7, 1958 (1/2 high waves)
Ritter Island NE New Guinea,1888 (5 km3)
Island of Reunion, 4000 years B.P.
Storegga, Norway, 30.000 years ago (3380 km3, 81.900 km2)
Norfolk Canyon Slide (150 km3, 3700 km2)
Nuuanu Landslide, Oahu, Hawaii, 2.7 Ma (5000 km3, 23.000 km2)
Volcano Ecuador, Galapagos, 100.000 years
Toulkeridis, 2005; adaptado d
Geist et al., 2002
Present Case Examples A:
The Cumbre Vieja volcano on the Canary Islands' La Palma
island
Present Case Examples B:
The Mauna Loa volcano on Big island Hawaii
Present Case Examples C:
Volcano Roca Redonda, Galapagos, Ecuador
Kurz et al., 2001
De La Torre, 2005
Wolf–Darwin lineament, Galapagos Spreading Ridge and
plume–ridge interaction in northern Galápagos
Four different trends of lineaments or fault systems (our study):
(from oldest to youngest)
a) NE-SW
(inactive, responsible for a previously unidentified partial sectorial collapse towards the West,
prior the emerge of the actual shield)
b) N-S
(most probably also inactive)
c) NW-SE
(active, parallel to the Wolf Darwin Lineament)
d) WNW-ESE
(active, rifting-like extensional opening, without an evident trace of faulting, partially filled up by
debris on its western side)
Three different trends of lineaments or fault systems (Glass et al., 2007):
Roca Redonda with ‘‘star’’-shaped morphology, which itself comprises six radial ridges ranging in
length from 5 to 10.5 km, forming three lineaments trending
a) NE–SW
b) W–E
c) NW–SE
Gracias
Prof. Dr. Theofilos Toulkeridis
M.Sc. Marcelo Cando Jacome
M.Sc. Giorgio de la Torre
Centro de Geologia, Volcanologia y Geodinamica
Servicio por la Ciencia y la Humanidad
Universidad San Francisco de Quito
[email protected], [email protected], 097 952701