Turrialba volcano's threat to the cities of the Central Valley of ...raman/papers2/CoV6 poster, Soto...
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Turrialba volcano's threat to the cities of the Central Valley of Costa Rica Gerardo J. Raúl SOTO , MORA , Mauricio MORA , Rafael BARQUERO , Waldo TAYLOR , Alberto VARGAS , Guillermo E. ALVARADO , Carlos RAMÍREZ , Gino GONZÁLEZ , Rolando MORA , Claudio PANIAGUA , José F. FERNÁNDEZ (1, 2, 3) (3, 4) (2, 3) (1, 3) (1, 3) (1, 3) (1, 2, 3) (3, 4) (3, 4) (2, 4) (1) (1) (1) Instituto Costarricense de Electricidad, (2) Escuela Centroamericana de Geología, Universidad de Costa Rica, (3) Red Sismológica Nacional, (4) Centro de Investigaciones en Ciencias Geológicas, Universidad de Costa Rica, San José, Costa Rica www.rsn.geologia.ucr.ac.cr/ E-mail: [email protected] References GONZALEZ VIQUEZ, C., 1910: Temblores, terremotos, inundaciones y erupciones volcánicas en Costa Rica 1608-1910. - Tipografía de Avelino Alsina, 239 pp. LINKIMER, L., 2003: Geotectónica del extremo oriental del Cinturón Deformado del Centro de Costa Rica. - 103 pp. Universidad de Costa Rica [Tesis Licenciatura]. REAGAN, M., DUARTE, E., SOTO, G.J. & FERNANDEZ, E., 2006: The eruptive history of Turrialba volcano, Costa Rica, and potential hazards from future eruptions. - In: Rose, W.I., Bluth, G.J.S., Carr, M.J., Ewert, J.W., Patino, L.C. & Vallance, J.W. (Eds.): Volcanic hazards in Central America. Geological Society of America Special Paper 412: 235-257, doi: 10.1130/2006.2412(13). SOTO, G.J., 1988: Estructuras volcano-tectónicas del Volcán Turrialba, Costa Rica, América Central. - Actas V Congreso Geológico Chileno, Santiago, 8-12 de agosto de 1988, Tomo III: I 163-I 175. On January 5-6, 2010, lithic ash was erupted due to strong fumarolic-phreatic activity from a small newly-opened fumarolic vent (T>500ºC). The very fine ashes distributed in well accordance to previous expectations, to southwest and west, reaching the capital, San José (35 km away). Above Intense fumarolic activity, drawn by Thomas Francis Meagher in 1858 ( 1860). Below: drawing by geologist Karl von Seebach in 1865, during eruption. Harper´s New Monthly Magazine, : Turrialba has had summit fumaroles at least since 1723 and a strombolian- vulcanian eruption occurred in 1864-66, severely affecting a radius of 3 km around the volcano, and blowing ashes over the capital San José, and down to the Pacific coast, ~130 km away. Since then, fumarolic activity (T~90ºC) has been present. Future eruptions (months to decades on), phreatic or magmatic, pose a major threat for farms and housing 5 km around the volcano and significant threats to agriculture, pastures and telecommu- nications on the western side of the volcano. The most likely “biggest- scenario eruption” would affect up to 1.5 million people (see above on prehistorical distribution of ashes) and aerial trans- portation, because the main Costa Rican international airport lies on the ash dispersion trend (see figure above on 1864 ash dispersal). Turrialba volcano lies on the easternmost edge of the Central Volcanic Range of Costa Rica, <30 km away from the western Central Valley (~2.1 million inhabitants in 2010). Since the winds mainly blow from the Caribbean into mainland (E-W), and Central Valley is downwind from Turrialba, this poses a potential major threat to cities in there. Six powerful eruptions have taken place from Turrialba during the last 3400 years, and isopachs show that ashfall mainly affected the western Central Valley (where the present cities of San José, Heredia and Alajuela lie) and lesser, the eastern Central Valley (where Cartago is). Turialba volcano and the Central alley of Costa Rica.The ellipsoidal contour is the 10-cm isopach of the plinian-subplinian eruption that occurred aprox. in 40 A.D (Reagan et al., 2006). The other two contours mark the possible limits of tephra fall during the last 3400 years. Prevailing winds blow to the W-SW. Higher winds blow to the NE. V Western Central Valley Barva V. Turrialba V. Irazú V. 0 10 km Eastern Central Valley Tectonic swarms with epicenters along the main tectonic feature (a SW-trending zone with craters, faults, pyroclastic cones and fumaroles) have been recorded at least since 1982. Seismicity 1992-1996 EQ swarm Sept. 1982 EQs 1991 5 km Aerial photograph and location of main seismicity in the surroundings of Turrialba volcano since 1982. A restless stage initiated in 1995 and particularly since 2007, when wider fumarolic areas (similar to those observed in the 1850s-60s, see above), escalating temperatures (T=200-300ºC) in them, and seismicity around the southwestern crater have appeared. Resulting acid rain (pH<5) has remarkably affected ~50 km on the western flank. 2 Epicenters early-mid April 2007 Epicenters mid-late April 2007 Epicenters Mayl 2007 New fracture with steaming in 2007 Location of main faults around the summit of Turrialba volcano (in red, from Soto, 1988; and Linkimer, 2003), and areas of seismicity since April 2007. km Epicenters June 2007-late 2009 May 17, 2009. Photo by A. Sanabria from 20 SW of the volcano N 0 2 km 560 556 564 220 224 216 Southwestern crater Area with occasional acid rain (pH<5.6) Area with frequent acid rain (pH<5.6) Areas affected by acid rain Aerial view, Dec. 26, 2009 ASERRI ALAJUELITA MORAVIA CORONADO SANTA CRUZ 5 km N TURRIALBA VOLCANO Distribution of ashes, January 5-6, 2010 Microphotography of the lithic ashes erupted on 01/05/2010 (Courtesy of Research Center in Microscopic Structures). New vent opened during the eruption in early January 2010. Oblique aerial view of the craters of Turrialba, with fumaroles from the SW crater and the new vent. Turrialba Volcano emits a translucent plume of volcanic gases in this natural-color satellite image from January 21, 2010. NASA Earth Observatory image by Robert Simmon, using EO-1 ALI data provided by the NASA EO-1 team. Caption by Robert Simmon. Available at http://earthobservatory.nasa.gov/images/ imagerecords/42000/42425/turrialba_ali_ 2010021_lrg.jpg. Different views of the exhalative (intense fumarolic) activity of the volcano. • From the northeast (far left). • From the southwest (upper center) • From the west (30 km away, lower) showing Irazú volcano with clouds in the foreground and Turrialba in the background. Upper right is the RSAM from the CIMA seismic station on the summit, from November 2009 to February 2010. There is a sharp change previous to the phreatic- fumarolic eruption in early January. First, a decrease and then an increase during the event. It is interpreted as a pressurization of the system due to fracture closure previous to the eruption. Time (days) Counts RSAM Eruption T Turrialba : C artago :C N Nicoya : J San José : A Present Airport : R San Ramón : P Puntarenas : Pacific Ocean Caribbean Sea Nicaragua Panama N P R A J C T Distribution of ashes between September 1864 and February 1866, drawn according to the accounts contained in González (1910). Turrialba volcano
Transcript of Turrialba volcano's threat to the cities of the Central Valley of ...raman/papers2/CoV6 poster, Soto...
Turrialba volcano's threat to the cities of the Central Valley of Costa Rica
Gerardo J. RaúlSOTO , MORA , Mauricio MORA , Rafael BARQUERO , Waldo TAYLOR ,Alberto VARGAS , Guillermo E. ALVARADO , Carlos RAMÍREZ , Gino GONZÁLEZ ,
Rolando MORA , Claudio PANIAGUA , José F. FERNÁNDEZ
(1, 2, 3) (3, 4) (2, 3) (1, 3) (1, 3)
(1, 3) (1, 2, 3) (3, 4) (3, 4)
(2, 4) (1) (1)
(1) Instituto Costarricense de Electricidad, (2) Escuela Centroamericana de Geología, Universidad de Costa Rica,(3) Red Sismológica Nacional, (4) Centro de Investigaciones en Ciencias Geológicas, Universidad de Costa Rica, San José, Costa Rica
www.rsn.geologia.ucr.ac.cr/ E-mail: [email protected]
References
GONZALEZ VIQUEZ, C., 1910: Temblores, terremotos, inundaciones y erupciones volcánicas en Costa Rica 1608-1910. - Tipografía de Avelino Alsina, 239 pp.LINKIMER, L., 2003: Geotectónica del extremo oriental del Cinturón Deformado del Centro de Costa Rica. - 103 pp. Universidad de Costa Rica [Tesis Licenciatura].REAGAN, M., DUARTE, E., SOTO, G.J. & FERNANDEZ, E., 2006: The eruptive history of Turrialba volcano, Costa Rica, and potential hazards from future eruptions. - In: Rose, W.I., Bluth, G.J.S., Carr, M.J.,Ewert, J.W., Patino, L.C. & Vallance, J.W. (Eds.): Volcanic hazards in Central America. Geological Society of America Special Paper 412: 235-257, doi: 10.1130/2006.2412(13).SOTO, G.J., 1988: Estructuras volcano-tectónicas del Volcán Turrialba, Costa Rica, América Central. - Actas V Congreso Geológico Chileno, Santiago, 8-12 de agosto de 1988, Tomo III: I 163-I 175.
On January 5-6, 2010, lithic ash was erupted due to strongfumarolic-phreatic activity from a small newly-opened fumarolicvent (T>500ºC). The very fine ashes distributed in well accordanceto previous expectations, to southwest and west, reaching thecapital, San José (35 km away).
Above Intense fumarolic activity, drawn by Thomas Francis Meagherin 1858 ( 1860). Below: drawingby geologist Karl von Seebach in 1865, during eruption.
Harper´s New Monthly Magazine,:
Turrialba has had summitfumaroles at least since1723 and a strombolian-vulcanian eruptionoccurred in 1864-66,severely affecting a radiusof 3 km around the volcano,and blowing ashes over thecapital San José, and downto the Pacific coast,~130 km away. Since then,fumarolic activity (T~90ºC)has been present.
Future eruptions (monthsto decades on), phreaticor magmatic, pose a majorthreat for farms andhousing 5 km around thevolcano and significantthreats to agriculture,pastures and telecommu-nications on the westernside of the volcano. Themost likely “biggest-scenario eruption” wouldaffect up to 1.5 millionpeople (see above onprehistorical distributionof ashes) and aerial trans-portation, because themain Costa Ricaninternational airport lieson the ash dispersiontrend (see figure aboveon 1864 ash dispersal).
Turrialba volcano lies on theeasternmost edge of the CentralVolcanic Range of Costa Rica,<30 km away from the westernCentral Valley (~2.1 millioninhabitants in 2010). Since thewinds mainly blow from theCaribbean into mainland (E-W),and Central Valley is downwindfrom Turrialba, this poses apotential major threat to cities inthere. Six powerful eruptions havetaken place from Turrialba duringthe last 3400 years, and isopachsshow that ashfall mainly affectedthe western Central Valley (wherethe present cities of San José,Heredia and Alajuela lie) andlesser, the eastern Central Valley(where Cartago is).
Turialba volcano and the Central alley of Costa Rica.The ellipsoidal contouris the 10-cm isopach of the plinian-subplinian eruption that occurred aprox. in40 A.D (Reagan et al., 2006). The other two contours mark the possible limitsof tephra fall during the last 3400 years. Prevailing winds blow to the W-SW.Higher winds blow to the NE.
V
WesternCentralValley
Barva V.
Turrialba V.
Irazú V.
0 10 km
EasternCentralValley
Tectonic swarms with epicentersalong the main tectonic feature(a SW-trending zone with craters,faults, pyroclastic cones andfumaroles) have been recorded atleast since 1982.
Seismicity 1992-1996
EQ swarm Sept. 1982
EQs 1991
5 km
Aerial photograph and location of main seismicityin the surroundings of Turrialba volcano since 1982.
A restless stage initiated in 1995 and particularlysince 2007, when wider fumarolic areas (similarto those observed in the 1850s-60s, see above),escalating temperatures (T=200-300ºC) in them,and seismicity around the southwestern craterhave appeared. Resulting acid rain (pH<5) hasremarkably affected ~50 km on the western flank.2
Epicenters early-mid April 2007
Epicenters mid-late April 2007
Epicenters Mayl 2007
New fracture with steaming in 2007
Location of main faults aroundthe summit of Turrialba volcano(in red, from Soto, 1988; andLinkimer, 2003), and areas ofseismicity since April 2007.
km
Epicenters June 2007-late 2009
May 17, 2009.Photo by A. Sanabria from20 SW of the volcano
N
0 2 km
560556 564
220
224
216
Southwestern crater
Area with occasional acid rain (pH<5.6)
Area with frequent acid rain (pH<5.6)
Areas affected by acid rain
Aerial view, Dec. 26, 2009
ASERRI
ALAJUELITA
MORAVIA
CORONADO
SANTA CRUZ
5 km
N
TURRIALBA VOLCANO
Distribution of ashes, January 5-6, 2010
Microphotographyof the lithic ashes
erupted on 01/05/2010(Courtesy of ResearchCenter in Microscopic
Structures).
New vent opened during the eruptionin early January 2010.
Oblique aerial view of the craters ofTurrialba, with fumaroles from the SWcrater and the new vent.
Turrialba Volcano emits a translucent plumeof volcanic gases in this natural-color satellite
image from January 21, 2010. NASA EarthObservatory image by Robert Simmon, using
EO-1 ALI data provided by the NASA EO-1 team.Caption by Robert Simmon. Available at
http://earthobservatory.nasa.gov/images/imagerecords/42000/42425/turrialba_ali_
2010021_lrg.jpg.
Different views of the exhalative (intensefumarolic) activity of the volcano.• From the northeast (far left).• From the southwest (upper center)• From the west (30 km away, lower)showing Irazú volcano with clouds in theforeground and Turrialba in the background.Upper right is the RSAM from the CIMAseismic station on the summit, fromNovember 2009 to February 2010. There isa sharp change previous to the phreatic-fumarolic eruption in early January. First,a decrease and then an increase duringthe event. It is interpreted as apressurization of the system due tofracture closure previous to the eruption.
Time (days)
Counts
RS
AM
Eruption
T Turrialba:
C artago: C
N Nicoya:
J San José:
A Present Airport:
R San Ramón:
P Puntarenas:Pacific Ocean
Caribbean
Sea
Nicaragua
Pan
am
a
N
P RA
JC
T
Distribution of ashes betweenSeptember 1864 and February 1866,drawn according to the accountscontained in González (1910).
Turrialbavolcano
