Is a zombie volcano a thing?
By Matt Pritchard, Maria Furtney, and Jennifer Cooper
The headline in Discovery News asked, “Zombie volcano or new supervolcano?” (http://news.discovery.com/earth/zombie-volcano-or-new-supervolcano-in-bolivia-111103.htm) My initial thought was, “Isn’t there an option C?” But my second thought was, “What is a zombie volcano?” To my knowledge, this article was the first usage of the term “zombie volcano” (November, 2011).
The article was about the PLUTONS project (http://plutons.science.oregonstate.edu), an international collaborative project involving institutions in Bolivia, Chile, Argentina, Canada, the UK, and USA to study two areas of ground uplift from magmatic accumulation in the central Andes Mountains with which we are involved. The areas of uplift were unusual for several reasons, including their large size (more than 70 km across) and the fact that neither uplift was obviously related to a volcano that had erupted in the last 10,000 years or more.
Specifically, the author of the article (Sarah Simpson) was interviewing a team of researchers at the University of California, Santa Cruz who were studying river terraces and lake shorelines at one of the uplift zones called Uturuncu volcano in Bolivia to determine how long the region had been uplifting. The satellite radar interferometry data that had discovered the uplift could only show that it had been ongoing since 1992 – if the geomorphologists could determine that it had been ongoing for centuries or millennia, it might indicate a large volume of magma had accumulated.
Now, whether the accumulated magma at Uturuncu will ever lead to an eruption or just be a benign intrusion is one of the research questions of the PLUTONS project, and is explained further in this post by team member Shanaka de Silva of Oregon State University (http://www.wired.com/2012/02/dr-shanaka-de-silva-answers-your-questions-about-supervolcanoes-uturuncu-and-more/). There is a history of supereruptions in the central Andes surrounding Uturuncu over the last 10 million years — that is, eruptions producing several hundred to several thousand cubic kilometers of ash that happen infrequently in Earth history (the last one was 26,000 years ago). But, a supereruption from Uturuncu does not seem very likely because the frequency of supereruptions has been waning over the last few million years in the central Andes. Further, an eruption of any kind from Uturuncu is not forecast with the available data – the magma doesn’t seem to be approaching the surface.
So, what of the zombie volcano option? Neither the scientists from the PLUTONS project nor the article author used the term, so we must thank (blame?) the Discovery News editor for its invention. My guess is that the phrase “zombie volcano” was meant to refer to a volcano that is seemingly dead, but showing signs of life. In the case of Uturuncu, the last eruption is thought to have been about 300,000 years ago and the volcano does indeed look very old with a deeply eroded profile. But this long interval between eruptions does not mean that Uturuncu is dead – several volcanoes in the central Andes have repose times of 100,000s of years (see Clavero et al., 2004). In fact, an even older volcano about 300 km to the northwest of Uturuncu called Sillajhuay also shows signs of life (ground deformation and seismicity: Pritchard et al., 2014) even though it hasn’t erupted in about 2.5 million years (Polanco & Gareweg, 2000). Are there now two zombie volcanoes?
Scientifically, there isn’t any need for the term zombie volcano. There are may examples of volcanoes laying apparently dormant for hundreds to thousands of years between eruptions (for example, El Chichon, Mexico, Fourpeaked, Alaska, Chaitén, Chile) – these aren’t zombies, just volcanoes that should still be considered active. Plus, there are many volcanoes that are known to be restless without eruption — the term “quiescently active” has been used to describe these volcanoes (Stix, 2007), and this classification could be applied to Uturuncu and Sillajhuay. There is a spectrum of volcano life cycles involving periods of activity and repose of different lengths, which makes hazard assessment difficult in some cases.
But, the term zombie volcano seems to have been embraced by popular culture. An iDevice game called “Zombie volcano” was released by Jared Bailey and is similar to his popular free game called “Baby Lava Bounce.” The game says “once upon a time, some zombies fell into a volcano” and you play as a bouncing/flying zombie who needs to “power up” by landing in other volcanoes. Also, a trailer for the soon to be released movie “Volcano Zombies” reveals a story “…about a sheriff who must rescue an estranged family from a mountain during a volcanic eruption and fight off a horde of lava-filled zombies that have shot out of the volcano, brought to life by a curse.” (http://www.dreadcentral.com/news/66923/explosive-first-trailer-for-volcano-zombies/#ixzz3DPa1mtwb) The movie has been called the “next Sharknado,” so watch out!
Clavero, J. E., R. S. J. Sparks, M. S. Pringle, E. Polanco, and M. C. Gardeweg. “Evolution and volcanic hazards of Taapaca volcanic complex, Central Andes of northern Chile.” Journal of the Geological Society 161, no. 4 (2004): 603-618.
E. Polanco, M. Gardeweg, Antecedentes preliminares de la estratigrafia volcanica del Cenozoico superior en los cuadrangulos Pampa Lirima y Cancosa, Altiplano de la I Region (19°45′–20°00′S y 69°00′–68°30′W), IX Congreso Geológico Chileno, Puerto Varas, Chile (2000), pp. 324–328
Pritchard, M. E., S. T. Henderson, J. A. Jay, V. Soler, D. A. Krzesni, N. E. Button, M. D. Welch, A. G. Semple, B. Glass, M. Sunagua, E. Minaya, A. Amigo, J. Clavero (2014) Reconnaissance earthquake studies at nine volcanic areas of the central Andes with coincident satellite thermal and InSAR observations, Journal of Volcanology and Geothermal Research
Stix, John. “Stability and instability of quiescently active volcanoes: The case of Masaya, Nicaragua.” Geology 35.6 (2007): 535-538.