Further Information

ResearcherID: A-4630-2011

Shanaka de Silva on Google Scholar

Shanaka de Silva on ORCID

Shanaka de Silva on LinkedIn

Areas of Specialization

Volcanology, Igneous Petrology, Volcano-Tectonics, Aeolian sedimentology/geomorphology, Terrestrial Planetary Surface Processes, Equity, Access and Inclusion

Research Interests

My primary research focus is understanding how volcanoes work and their associated hazards, with a focus on explosive volcanism. Volcanism and tectonism are inevitably linked and this has led to consortium efforts to understand linkages between magmatism and tectonics.

Some core themes in our research efforts are:

• Magmatism and volcanism in volcanic arcs - Cause and consequences of episodic behaviour of arcs; steady state vs flare-up modes
• Physical volcanology - dynamics of pyroclastic density currents, lahar sedimentology, eruption and emplacement of crystal-rich silicic lava
• Petrology of explosive volcanic eruptions - zoning in magma chambers, evidence recharge as an eruption trigger/initiator, time-scales of magma ascent
• Explosive and effusive eruptions of crystal–rich lava - post-caldera eruptions, feedbacks between vesiculation-ascent-rate and crystal framework integrity
• Caldera (super)volcanism - Thermomechanical feedbacks in initiating catastrophic eruptions, resurgence at large calderas
• Volcano-plutonic connection - Architecture of pre-eruptive magma systems, magma residence, geophysical, chronologic, and petrologic insights
• The link between magmatism, volcanism, and tectonics - magmatic contribution to plateau uplift, tectonic controls on magmatism and volcanism
• Geologic and probabilistic hazard assessment of volcanoes in individual volcanoes and volcanic fields
• Distributed Basaltic Volcanism as a volcanic hazard and as a probe into source processes

An enduring theme of our volcanological studies has been comprehensive field studies. These provide the volcanological and stratigraphic framework for subsequent detailed chronochemical studies that reveal pre-eruptive storage time scales and magmatic architecture of magma reservoirs and their geophysical expressions. Ultimately we have tried to use this insight to understand thresholds for eruption vs storage of magma and the character of the eventual eruptions. To investigate these phenomena I use the volcanologists toolbox (Petrology (particularly microanalysis), Geochemistry, Physical Volcanology, Geochronology, Remotely Sensed data, Geophysics) at all different scales. I like to think of this as "Volcano Forensics" - a CSI approach to volcanology. I am not an “expert” in any particular analytical technique, but I look for different tools and creative solutions for problems of interest most often in collaboration with more knowledgeable colleagues, many of whom are diverse early career folk.

Over the years we have used our broad understanding of volcanic processes to address volcanic hazards in Peru, Sumatra, and Saudi Arabia with new efforts in probabilistic hazard assessment.

Our current research projects take us to the Andes (Chile, Peru, Argentina, Bolivia), Indonesia (Toba, Sinabung volcanoes), China/North Korea (Changbaishan), Japan (Unzen and SW Hokkaido), and Saudi Arabia (Harrat Khaybar). To realize these projects we collaborate extensively, particularly with the excellent labs at my home institution of Oregon State University, and many others around the world.

This video is an outreach piece we made for our work at the Toba caldera. It features former PhD. student Adonara Mucek who worked on Toba caldera.

YouTube video: Volcano Comeback: Understanding Resurgence at Lake Toba

I also have active research interests in aeolian geomorphology and associated planetary analogs. As a volcanologist, why am I interested in aeolian geomorphology? While studying volcanic features in the high Andes, we couldn't ignore the fact that wind was producing an other-world landscape that was a valuable analog for the surface of Mars. Starting with yardangs, we have begun to address how the wind erodes and modifies high desert volcanic landscapes. Our latest work is trying to understand how gravel dominated bedforms form and applying cosmogenic isotopes to measure rates of aeolian erosion of ignimbrite. We apply our insights into how aeolian processes might be operating on other planetary surfaces, particularly Mars.

The broader impacts of our work relate to volcanic hazards, planetary surface processes, volcanism and climate, and Earth Science Education and Outreach (Visit our VolcanoWorld website). I am also committed to undergraduate research particularly for those from under-represented communities through activities that increase equity, access, and inclusion in the Earth Sciences - see our efforts through the Increasing Diversity in Earth Sciences and the LBOS Geobridge programs.

Education

B.Sc (Hons) Geology, University of Southampton, United Kingdom, 1982
PhD Earth Sciences, Open University, United Kingdom, 1987

Current Courses taught at OSU

GEO 305 – Living with Active Cascade Volcanoes; GEO 203 - Evolution of Planet Earth (sabbatical replacement); GEO 315 - Earth Materials II:Petrology; GEO 427/527 – Volcanology; GEO 699 Advanced Volcanology

Graduate Students

Current Graduate Students

• Charles Lewis (PhD) Constraining the magmatic and pre-eruptive evolution of flare-up related silicic magmatic systems
• Abdullah Alohali (PhD) Constraining the eruptive and magmatic history and origin of evolved magmas at Harrat Khaybar, Saudi Arabia
• Abby Gillen (PhD) Explosive silicic volcanism in Southern Peru - Ticsani and Huaynaputina
• Verenice Becerill Gonzalez (MS) Enigmatic silicic phreatomagmatism in the Altiplano of Bolivia - Cerro Volcan Quemado

Recent Graduate Theses (Primary Advisor unless stated)

• Daniel Bertin (PhD) Spatiotemporal analysis of volcanism in the southern Central Andes (University of Auckland; co-advisor with Jan Lindsay, Shane Cronin)
• Abdullah Alohali (MS, 2021) Spatiotemporal assessment of volcanic Hazards of Harrat Khaybar, Saudi Arabia
• Jordan Lubbers (PhD, 2021 co-advisor with Adam Kent) Storage Conditions in Large Silicic Magma Reservoirs
• Michelle Neely (MS 2019) Pattern to Process: morphometry and process in gravel megaripples in the Puna of Argentina
• Jade Bowers (MS 2019) Petrological Forensics at Sinabung Volcano, Sumatra (see Sinabung 2018 on YouTube)
• Katharine Solada (MS 2018) Paleomagnetic correlation and timescale of resurgence at Toba, Sumatra
• Adonara Mucek (PhD 2017) Resurgence at Toba Caldera, Sumatra
• Bethany Murphy (MS 2015) Timescales of silicic magmatic processes: U-Series zircon chronochemistry of Mt Unzen, Japan
• Stephanie Grocke (PhD 2014) Magma Dynamics and Evolution in Continental Arcs: Insights form the Central Andes
• Dale Burns (PhD 2014, co-advised wth Frank Tepley) Crustal Architecture and Magma Dynamics in a Large Continental Magmatic System: A Case Study of the Purico-Chascon Volcanic Complex, Northern Chile
• Jason Kaiser (PhD 2014) Understanding Large Resurgent Calderas and Associated Magma Systems: The Pastos Grandes Caldera Complex, Southwest Bolivia
• Jamie Kern (MS 2012) The plutonic record of the Altiplano Puna Volcanic Complex revealed by zircon chronology
• Rodrigo Iriarte (MS 2012) The Cerro Guacha Caldera Complex, SW Bolivia: stratigraphy, volcanology, and magma dynamics
• Casey Tierney (MS 2011) Timescales of silicic magmatic processes: U-Series chronochemistry of effusive domes of the Altiplano Puna Volcanic Complex.
• Chris Folkes (Ph.D. 2011) Physical Volcanology and Magmatic evolution of the Cerro Galan Caldera Complex, NW Argentina. (Monash University, Co-advisor w/Ray Cas, Heather Wright)
• Chris Harpel (Ph.D. 2010), Lahar sedimentology and hazards of the 2ka eruption of El Misti, southern Peru
• Robert Peckyno (MS - 2010), Morphometric parameters of terrestrial lavas
• Mangon Abot (MS - 2010), Amphibole-Plagioclase P-T estimates for the Altiplano Puna Volcanic Complex (Co-advisor with Anita Grunder)

Former Advisees and Co-Advisees – where are they now?

• Daniel Bertin - SERNAGEOMIN (Geological Survey), Chile
• Jordan Lubbers - USGS Mendehall Post-doc, AVO
• Jade Bowers, PhD Student, Boise State University
• Katharine Solada, Geology Instructor, Yakima Valley College, WA
• Adonara Mucek, STEM curriculum designer, Singapore
• Bethany Murphy, Engineering Geologist, Auckland, New Zealand
• Stephanie Grocke, Owner, Syncline Consulting, Truckee, NV
• Dale Burns, Research Faculty, Stanford University
• Jason Kaiser, Associate Professor, Department Chair, Southern Utah University
• Chris Folkes, Geologist, Geological Survey of New South Wales
• Rodrigo Iriarte , Professor and Department Head, Universidad Major San Andres, La Paz, Bolivia,
• Jamie Kern, Informal Educator, National Park Service
• Casey Tierney, Assistant Teaching Professor, Northern Arizona University, Flagstaff, AZ
• Chris Harpel, VDAP, USGS, CVO Vancouver, WA
• Mangon Abot, Program Head, Malaysian Geological Survey,

Hosted/Sponsored Post docs / Research Visitors

• Alejandro Cisneros de Leon (2023 - 2025) NSF Postdoctoral Fellow CEOAS
• Agostina Chiodi (2023 - 2024) CONICET, Argentina (Visiting Courtesy Faculty currently at CEOAS)
• Walter Baez (2023 - 2024) CONICET, Argentina (NSF funded visiting fellow currently at CEOAS)
• Shimpei Uesawa (2017-2018) CRIEPI, Japan
• Diane Smith (2019) Trinity University, TX (Sabbatical Visit)
• Johan Varekamp (2017) Wesleyan University, CT, USA (Sabbatical Visit)
• Seiko Yamasaki (2016-2017) Institute of Earthquake and Volcano Geology, Geological Survey of Japan
• Akihiko Tomiya (2014-2015) Institute of Earthquake and Volcano Geology, Geological Survey of Japan
• Bo Pan - (2013-2014 and 2018-2019) Chinese Earthquake Administration, Beijing
• Mauro Spagnuolo (2012 - 2014) - NASA funded CONICET Research Fellow and Instructor at Universidad Buenos Aires, Argentina

Publications

Recent papers since 2020 (Student authors identified with *; Post doc/Early Career colleague ‡ )

1. Iriarte R*‡, de Silva SL de, Schmitt AK, Jimenez NJ (2024) The Cerro Guacha Caldera complex, SW Bolivia: A long-lived, multicyclic, resurgent caldera complex in the Altiplano-Puna Volcanic Complex of the Central Andes. J Volcanol Geotherm Res 446:107988. doi:10.1016/j.jvolgeores.2023.107988
2. Kobayashi M., Okumura S., Sasaki O., de Silva S.L. 2023. The role of decompression history in gas bubble formation in crystal-rich silicic magma: Gas retention versus segregation. J Volcanol Geotherm Res 107844. doi:10.1016/j.jvolgeores.2023.107844
3. Zimbelman, J., Spagnuolo, M.‡, de Silva S.L., 2023. Aerodynamic Roughness Height of Gravel-Covered Plains in the Puna of Argentina. The Planetary Science Journal of the AAS doi:10.3847/PSJ/accdd9
4. Bertin D.*, de Silva S.L., Lindsay, J.M., Cronin, S., Caffe, P., Connor, C.B., Grosse, P., Baez, W., Bustos, E., and Constantinescu, R., 2023. Magmatic addition rates reveal flare-up and steady-state magmatism in the Central Andean arc. Nature Communications Earth and Environment 4, 75. doi:10.1038/s43247-023-00744-2
5. Burns, D.H.‡, de Silva, S.L., 2023. Andesites and evolution of the continental crust: Perspectives from the Central Volcanic Zone of the Andes. Frontiers Earth Sci 10, 961130. doi:10.3389/feart.2022.961130
6. Pan, B.‡, de Silva, S.L., Danišík, M., Schmitt, A.K., Miggins, D.P., 2022. The Qixiangzhan eruption, Changbaishan-Tianchi volcano, China/DPRK: new age constraints and their implications. Nature Scientific Reports 12, 22485. doi:10.1038/s41598-022-27038-5
7. Alohali, A.*, Bertin, D.*, de Silva, S.L., Cronin, S., Duncan, R., Qaysi, S., Moufti, M.R., 2022. Spatio-temporal forecasting of future volcanism at Harrat Khaybar, Saudi Arabia. Journal of Applied Volcanology 11, 12. doi:10.1186/s13617-022-00124-z
8. Bertin, D.*, Lindsay, J.M., Cronin, S.J., de Silva, S.L., Connor, C.B., Caffe, P.J., Grosse, P., Báez, W.‡, Bustos, E.‡, Constantinescu, R.‡, 2022. Probabilistic Volcanic Hazard Assessment of the 22.5–28°S Segment of the Central Volcanic Zone of the Andes. Frontiers Earth Sci 10, 875439. doi:10.3389/feart.2022.875439
9. Lubbers, J.*, Kent, A.R., and de Silva, S.L., 2022 Thermal budgets of magma storage constrained by diffusion chronometry: the Cerro Galán ignimbrite. Journal of Petrology, 63, p.1-19. doi:10.1093/petrology/egac048
10. Cisneros de Leon, A.‡, Mittal, T.‡, de Silva, S.L., Self, S., Schmitt, A.K., and Kutterolf, S., 2022. On Synchronous Supereruptions, Frontiers in Earth Science-Volcanology, 10, 827252. doi:10.3389/feart.2022.827252
11. Lewis, C.T.*, de Silva, S.L., and Burns, D.H.‡, 2022. Rhyolitic Melt Production in the Midst of a Continental Arc Flare-Up - The Heterogenous Caspana Ignimbrite of the Altiplano-Puna Volcanic Complex of the Central Andes. Geosphere, doi:10.1130/ges02462.1
12. de Silva, S.L., Self, S., 2022. Capturing the Extreme in Volcanology: The Case for the Term “Supervolcano.” Frontiers Earth Sci 10, 859237. doi:10.3389/feart.2022.859237
13. de Silva, S.L., Roberge, J., Bardelli*, L., Báez, W‡., Ortiz, A.‡, Viramonte, J.G., Arnosio, M., and Becchio, R., Magmatic evolution and architecture of an arc-related, rhyolitic caldera complex: The Late-Pleistocene to Holocene Cerro Blanco Volcanic Complex, Southern Puna, Argentina. Geosphere, doi:10.1130/ges02294.1
14. Burns, D.H.**, de Silva, S.L., Shane, P., and Coble, M.A.**, 2022. Crustal Forensics at Putauaki (Mt. Edgecumbe), New Zealand reveal the influence of deep arc crust on magma evolution in the Taupo Volcanic Zone. Contributions to Mineralogy and Petrology, v.117, 16. doi:10.1007/s00410-021-01875-5
15. Mucek*, A., Danišík, M., de Silva, S.L., Miggins, D.E., Schmitt, Pratomo, I., A.K., Koppers, A., and Gillespie, J., 2021. Bayesian analysis of coupled 40Ar/39Ar and (U/Th)/He thermochronometry reveals cold-stored regions of long-lived warm magma erupted at Toba Caldera, Sumatra” Communications Earth and Environment, 2, 185. doi:10.1038/s43247-021-00260-1
16. Solada, K. E.*, Reilly, B.T.‡, Stoner, J.S., de Silva, S.L., Mucek, A.E.*, Hatfield, R.G.‡, Pratomo, I., Jamil, R., and Setianto, B., 2020. Paleomagnetic Observations From Lake Sediments on Samosir Island, Toba Caldera, Indonesia, and Its Late Pleistocene Resurgence. Quaternary Research 95. Cambridge University Press: 97–112. doi:10.1017/qua.2020.13.
17. Pan, B.‡, de Silva, S.L., Xu, J., Liu, S., and Xu, D., 2020. Late Pleistocene to Present Day Eruptive History of the Changbaishan-Tianchi Volcano, China/DPRK: New Field, Geochronological and Chemical Constraints. Journal of Volcanology and Geothermal Research 399 (July). Elsevier B.V.: 106870. doi:10.1016/j.jvolgeores.2020.106870.
18. Báez, W.‡, de Silva, S.L., Chiodi, A., Bustos, E.**, Giordano, G., Arnosio, M., Suzaño, N., Viramonte, J.G., Norini, G., and Groppelli, G., 2020. “Pulsating Flow Dynamics of Sustained, Forced Pyroclastic Density Currents: Insights From a Facies Analysis of the Campo De La Piedra Pómez Ignimbrite, Southern Puna, Argentina” Bulletin of Volcanology, 1–32. doi:10.1007/s00445-020-01385-5