John J. Sánchez

This is me, in my cubicle at the GI.

I graduated with a Ph.D. in Geophysics from the Geophysical Institute, University of Alaska, Fairbanks.

I worked with Prof. Stephen R. McNutt . My research work was mostly related to volcano seismology and earthquake seismology in Alaska and elsewhere. I served as a seismologist for both the Alaska Volcano Obsevatory, and the Alaska Earthquake Information Center

Starting March 17, 2005,
please contact me at

johnjsanchez@gmail.com


Photos from Field work at Aniakchak caldera Summer 1999.
Photos from Colima Volcano Workshop, Mexico Spring 2000.
Photos from Trip to the Katmai Volcanoes June 2000.
Photos from Field wotk at Veniaminof volcano July 2001.
Photos from Seismology Training Course, Chile Oct.-Dec. 2001.
Photos from CSAV-2003 Training course in Volcano Hazards Monitoring, Hawaii June-July 2003.
Photos from Soufriere Hills volcano and work at Montserrat Volcano Observatory, August-September 2003.

Academic Background

Ph.D. Geophysics, University of Alaska Fairbanks. 2005. Thesis: "Volcano Seismology from Around the World: Case Studies from Mount Pinatubo (Philippines), Galeras (Colombia), Mount Wrangell and Mount Veniaminof (Alaska)."

M.S. Geophysics, University of Alaska Fairbanks. 2000. Thesis: "Inversion of Focal Mechanism Data for the Directions of Stress Near Redoubt Volcano, Alaska."

C.T. Computers Science. Universidad de Manizales, Colombia. 1998.

B.S. Geology, Universidad de Caldas, Colombia. 1996. Thesis: "Coda Q Before and After the Eruptions of 13 November 1985, and September 1 1989, at Nevado del Ruiz Volcano, Colombia." (In Spanish). Co-author: Luis Eduardo Toro.


Ph.D. Thesis Project

My Ph.D. thesis includes case studies on various topics on seismology at volcanoes around the world. The manuscript is composed of six papers plus an appendix and topics are as follows: b-value mapping at Mt. Pinatubo, Philippines, and Galeras Volcano, Colombia; the response of Mt. Wrangell and Mt. Veniaminof, Alaska, to the November 3 2002, Mw 7.9 Denali Fault Earthquake; the volcano-tectonic seismicity at Mt. Veniaminof Volcano, and the complex frequencies of long-period events at Mt. Veniaminof. The appendix is the documentation of the response of Mt. Wrangell volcano, Alaska, to the surface waves from the December 26, 2004, Mw 9.0 Sumatra-Andaman Islands Earthquake (Mt. Wrangell responded with a short-lived flurry of small local earthquakes). An abstract was submitted to the 2005 meeting of the Seismological Society of America (West, et al.).

Other Research Interests

Other research interests include stress inversion methods, activity at volcanoes triggered by distant earthquakes and the study of attenuation at or near volcanoes using coda waves of vt earthquakes.


Experience

I have been involved in seismology and volcano monitoring since 1992, when I joined the Observatorio Vulcanológico y Sismológico de Manizales, Colombia (OVSM) as a student assistant. Under the supervision of senior scientists there we kept track on the activity at several volcanoes in the northermost volcanic zone of South America, including: Cerro Bravo, Nevado del Ruiz, Santa Isabel, Nevado del Tolima and Cerro Machin volcanoes.

Routine duties were the change of records as activity demanded (twice a day, during quiet times), event count and classification, reading of parameters such as peak-to-peak amplitude, period, and coda duration, location of Volcano-Tectonic (VT) and Long-Period (LP) earthquakes, and fault plane solution calculation for relevant VT earthquakes. These tasks were carried out using both analog (smoked paper records from drum recorders) and digital signals (recorded on PC with the Willy Lee system and on UNIX machines with a Japanese system).

In 1998 I was a awarded a FULBRIGHT scholarship and came to the US to begin graduate studies in geophysics. While doing this, I have had the opportunity to visit several other volcano observatories and earthquake monitoring facilities including those in Mexico, Chile, Hawaii, and more recently, Montserrat (West Indies). Future plans: return to Latin America to work actively in the monitoring of volcanoes and earthquake activity, for there is a great need of personnel with expertise in these areas.


Publications

** Abstracts of published papers are available on line by following the links. If you would like a reprint or preprint of a paper, just send me an e-mail :)

Papers


Sánchez, J. J. A Velocity Model for Mt. Veniaminof, Alaska: Volcano-Tectonic Seismicity and Implications for an Active Magmatic System. Submitted to Journal of Volcanology and Geothermal Research.

Sánchez, J. J., McNutt, S. R., Kumagai, H., Gil-Cruz, F., and Londoņo, J. M. Temporal Variations in the Complex Frequencies of Long-Period Seismic Events at Mt. Veniaminof, Alaska. Submitted to Journal of Volcanology and Geothermal Research.

Sánchez, J. J. and S. R. McNutt Intermediate-Term Declines in Seismicity at Mt Wrangell and Mt. Veniaminof Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake Bulletin of the Seismological Society of America, Vol 94 No 6B, S370-S383

Sánchez, J. J. and S. R. McNutt. Unexpected response of Mt. Wrangell volcano, Alaska, to the shaking from a large regional earthquake: A puzzle for intermediate-term earthquake-volcanoes interactions. Earth Sciences Research Journal, Vol 8, 1, 34-44

Sánchez, J. J., D. M. Gómez, R. A. Torres, M. L. Calvache, A. Ortega, A. P. Ponce, A. P. Acevedo, F. Gil-Cruz, J. M. Londoņo, S. P. Rodriguez, J de J. Patiņo and O. P. Bohorquez. Spatial mapping of the b-value at Galeras volcano, Colombia, using earthquakes recorded from 1995 to 2002. Article in Press, Earth Sciences Research Journal.

Sánchez, J.J., S. R. McNutt, J. A. Power, and M. Wyss (2004). Spatial Variations in the Frequency-Magnitude Distribution of Earthquakes at Mount Pinatubo Volcano. Bulletin of the Seismological Society of America, 94,2, 430-438.

Sánchez, J. J., M. Wyss, and S. R. McNutt (2004). Temporal-spatial variations of stress at Redoubt volcano, Alaska, inferred from inversion of fault plane solutions. Journal of Volcanology and Geothermal Research, 130, 1-30.

Moran, S.C., Power, J.A., Stihler, S.D., Sánchez, J.J., and Caplan-Auerbach, J. Earthquake Triggering at Alaskan Volcanoes following the November 3, 2002, Denali Fault earthquake. Bulletin of the Seismological Society of America, Vol 94 No 6B, S300-S309

Power, J.A., Moran, S.C., McNutt, S.R., Stihler, S.D., and Sánchez, J.J. (2001). Seismic response of the Katmai volcanoes to the 6 December 1999 magnitude 7.0 Karluk lake earthquake, Alaska. Bulletin of the Seismological Society of America, 91, 1, pp. 57-63.

Londoño, J.M., J. J. Sánchez, L.E. Toro, F. Gil, and O. P. Bohorquez (1998). Coda Q before and after the eruptions of 13 November 1985, and 1 September 1989, at Nevado del Ruiz volcano, Colombia. Bulletin of Volcanology, 59, 556-561.


Reports


Dixon, J. P., S. D. Stihler, J. A. Power, G. Tytgat, S. C. Moran, J. J. Sánchez, S. R. McNutt, S. Estes, and J. Paskievitch (2004). Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 Through December 31, 2003. U. S. Geological Survey Open-File Report 2004-1234, 69p.

Dixon, J. P., S. D. Stihler, J. A. Power, G. Tytgat, S. C. Moran, J. J. Sánchez, S. Estes, S. R. McNutt, and J. Paskievitch (2003). Catalog of Earthquake Hypocenters at Alaskan Volcanoes: January 1 Through December 31, 2002. U. S. Geological Survey Open-File Report 03-267, 58p.


Abstracts in conferences proceedings


Sánchez, J. J. and S. R. McNutt (2004). Seismicity of Mt. Veniaminof, Alaska: Implications for an active magmatic system. Eos Trans. AGU, 85(47), Fall Meet. Suppl., Abstract V14B-07.

Sánchez, J. J. and S. R. McNutt (2004). Constraints in the locations of earthquakes at Mount Veniaminof, Alaska. Conference Proceedings of the 2004 IAVCEI General Assembly. Pucón, Chile, November 15-19, 2004.

Sánchez, J. J. and S. R. McNutt (2004). Unexpected Response of Mt. Wrangell Volcano, Alaska, to the Shaking from a Large Regional Earthquake: A Puzzle for Intermediate-Term Earthquake-Volcano Interactions Conference Proceedings of the First Latin American Congress on Seismology and Second Colombian Congress on Seismology, Armenia, Colombia, August 16-21, 2004.

Sánchez, J. J., D. M. Gómez, R. A. Torres, M. L. Calvache, A. Ortega, A. P. Ponce, A. P. Acevedo, F. Gil-Cruz, J. M. Londoņo, S. P. Rodriguez, J de J. Patiņo and O. P. Bohorquez. Mapeo Espacial del Parametro b en el volcan Galeras, Colombia. Conference Proceedings of the First Latin American Congress on Seismology and Second Colombian Congress on Seismology, Armenia, Colombia, August 16-21, 2004.

Sánchez, J. J. and S. R. McNutt (2004). Drops in seismicity at two volcanoes in Alaska after the Denali earthquake American Association for the Advancement of Science, Ann. Meet., Seattle, 12-16 Feb. 2004, student poster 120, p. A134-A135 (Abstracts CD).

Sánchez, J. J. and S. R. McNutt (2003). Intermediate-Term Declines in Seismicity at Mt. Veniaminof and Mt. Wrangell Volcanoes, Alaska, Following the Mw 7.9 Denali Fault Earthquake. Summer School on Tectonic-Magmatic Interaction 31 August - 8 September, 2003 Geysir, South Iceland. Abstract volume, Thóra Árnadóttir and Freysteinn Sigmundsson (editors), Nordic Volcanological Institute report 0303, p 45.

Sánchez, J. J. and S. R. McNutt (2003). Intermediate-Term Declines in Seismicity at Mt. Veniaminof and Mt. Wrangell Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake 54th Arctic Science Conference, AAAS-Arctic Division "Extreme Events, Understanding Perturbations to the Physical and Biological Environment." Fairbanks, AK., 21-24 September 2003, p.53.

Sánchez, J.J., M.L. Calvache, A. P. Acevedo, C.A. Garzon, and F. P. Rodriguez (2003). Extreme events in Colombia: Lessons learned and implications of the eruptions of Nevado del Ruiz and Galeras volcanoes, Colombia 54th Arctic Science Conference, AAAS-Arctic Division "Extreme Events, Understanding Perturbations to the Physical and Biological Environment." Fairbanks, AK., 21-24 September 2003, p.168.

Sánchez, J. J. and S. R. McNutt (2003). Intermediate-Term Declines in Seismicity at Mt. Veniaminof and Mt. Wrangell Volcanoes, Alaska, Following the November 3, 2002 Mw 7.9 Denali Fault Earthquake Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract S12A-0375.

Sánchez, J.J. and S. R. McNutt (2002). Search for a Possible Triggering Effect Between Tectonic Earthquakes and Swarms at Volcanoes Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract V21A-1163.

Sánchez, J.J., M. Wyss, S. R. McNutt, and J. A. Power (2001). Spatial variations in the frequency-magnitude distribution of Earthquakes at Mount Pinatubo volcano. Eos Trans. AGU, 82(47), Fall Meet. Suppl., Abstract U32A-0003.

Sánchez, J.J., M. Wyss, and S. R. McNutt (2000). Inversion of Focal Mechanism Data for the Directions of Stress at Redoubt Volcano, Alaska. Eos Trans. AGU, 81(48), Fall Meet. Suppl., Abstract V21B-04

Sánchez, J.J., and S. R. McNutt (2000). New Composite Focal Mechanisms at Four Alaskan Volcanoes. Septima Reunion Internacional "Volcan de Colima", Marzo 6-10, 2000, Colima, Mejico.

McNutt, S. R., J. J. Sánchez, M.E. Pritchard, M. Sunagua, R. Muranca, C. Annen, M. Humphreys, A le Friant, R.S.J. Sparks, and J. Clavero (2004). Seismic and geodetic activity at Uturuncu volcano, Bolivia. Conference Proceedings of the 2004 IAVCEI General Assembly. Pucón, Chile, November 15-19, 2004.

McNutt, S.R., J. J. Sánchez, S. C. Moran, and J. A. Power (2003). Intermediate-Term Declines in Seismicity at Two Volcanoes in Alaska Following the Mw7.9 Denali Fault Earthquake Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract S72F-1353, pp F1723.

Moran, S.C., J. J. Sánchez, J. A. Power, S. D. Stihler, and S. R. McNutt (2003). Remotely Triggered Seismicity at Alaskan Volcanoes Following the Mw 7.9 Denali Fault Earthquake Eos Trans. AGU, 84(46), Fall Meet. Suppl., Abstract S72F-1352, pp F1723.

Power, J.A., Moran, S.C., McNutt, S.R., Stihler, S.D., and Sánchez, J.J. (2000). Triggered Seismicity Beneath the Katmai Volcanoes Following the December 6, 1999 Magnitude 7.0 Karluk Lake Earthquake, Alaska. Eos Trans. AGU, 81(48), Fall Meet. Suppl., Abstract S21C-05.

McNutt S. R., and Sánchez, J.J. (2000). Composite Focal Mechanisms at Four Alaskan Volcanoes. 95th annual meeting of the Seismological Society of America, 9-12 April 2000, San Diego, CA, USA.


Awards and Scholarships

- FULBRIGHT-COLCIENCIAS Scholar 1998-2000.
- "Robert I. Larus" Student Prize at the AAAS (American Association for the Advancement of Science) Conference, Arctic Chapter. Best student paper. Fairbanks, AK, 2003.


Helping Earth-Sciences libraries in developing countries

With the sponsorship of IAVCEI and the K. B. Mather library at the Geophysical Institute, University of Alaska, Fairbanks we started a program of donations in 2001. We collect reading materials and ship them to the libraries of volcano observatories and Geology departments located in developing countries. The materials consist mostly of used textbooks and issues of professional journals on Earth Sciences, but also we collect textbooks on mathematics, physics, chemistry and computer science. At the beginning, most books and journals came from the duplicates collection of the K. B. Mather library, but with time others joined the cause and we started receiving donations from active and retired scientists who wished to put a good use to their old books (sometimes not-so-old!). If you want to join, There are two ways in which you may help: 1) Donating materials, and, 2) Helping in the packing and shipping boxes on your spare time. If interested, please contact: Tanja Petersen (tanja@gi.alaska.edu), Celso Reyes (celso@giseis.alaska.edu or Steve McNutt (steve@giseis.alaska.edu). BIG THANKS to all of you who had helped this project throughout the years.
JJ (01/05).