Bombturbation – a Technocene sediment-transport process

Since reading Roger Hooke’s work on humans as agents of quantifiable geomorphic change (Hooke 1994, 2000; Haff 2003; Hooke & Martin-Duque 2012), I’ve wondered about bombs. (To keep from sounding glib about or oblivious to the very real and very human implications of mechanized warfare, for the purpose of this discussion I’ll “wonder about bombs” in the comparatively benign context of a bombing range or similar — someplace where people aren’t.) Bombs dropped on a practice field throw around a lot of dirt. They put big holes in the ground. And humans have used them in staggering quantity in the past 100 years. Analogously, sediment transport by rain splash — the effect of impact and ejection that a rain drop has on movable sediment — has fascinated researchers interested in landscape dynamics since the 1940s (Ellison 1944; and for a sharp summary, see Furbish et al. 2009). Perhaps bombs might constitute their own kind of sediment transport mechanism?

Turns out there’s a term for it. Joseph Hupy and Randy Schaetzel introduced “bombturbation” in an article in the journal Soil Science in 2006 (Hupy & Schaetzel 2006), characterizing bombing in terms of other soil mixing processes (“pedoturbation”). The late Francis Hole discussed “anthroturbation” in his 1961 pedoturbation classification scheme (Hole 1961), but Hupy & Schaetzel (2006) include bombing as a close cousin of “impacturbation”: the kind of sediment mixing caused by an extraterrestrial object (like a meteorite) striking a terrestrial surface (whether the Earth’s, the Moon’s, or otherwise).

Hupy, especially, has continued to investigate warfare as a geomorphological process, exploring (with coauthors) the topic in several papers: “The Environmental Footprint of War” (Hupy 2008); “Soil Development on the WWI Battlefield of Verdun, France” (Hupy & Schaetzl 2008); and “Modern Warfare as a Significant Form of Zoogeomorphic Disturbance upon the Landscape” (Hupy & Koehler 2012), in which the authors compare sobering topographic rearrangements still evident at Verdun, France, and at Khe Sanh, Vietnam.

Where the plow is perhaps the iconic tool of the Anthropocene, the bomb may be a tool particular to the Technocene, an even finer splitting of the present geologic epoch. (Not to be confused with the “techno scene” — although a Google Scholar search does yield some interesting papers regarding the advent of the club drug Ecstasy in the late 1990s.) The distinction between the Anthropocene and Technocene arguably has less to do with when human social organization began to alter Earth’s physical environment in appreciable ways and more to do with the broader concept of technology as a sphere of Earth system dynamics unto itself (see Peter Haff’s brief discussion of the technosphere at the end of his 2012 paper in Earth System Dynamics here, or Robert Wright’s monograph Nonzero). Plenty of specific technology types drive physical landscape transformations — intensive, sustained mining for the rare-earth elements used in phones and computers, for example. If alien stratigraphers were to land on the future Earth and drill a core to puzzle out from a sedimentological record the large-scale dynamics of human existence, bombturbation — or even erosion driven by agriculture — might be too fine a process of sediment transport for them to resolve. Other soil-mixing mechanisms will eventually smooth away the visual evidence of bombed terrain. However, weaponization of atomic technology has left what we might consider Technocene time stamps in sediments and biological tissues around the globe. Much as we parse other isotopic ratios to peer into Earth’s deep time, the geology of the Anthropocene is already stratified by nuclear clocks that we designed (to say nothing of shrapnel, plastics, and other related, persistent debris). And future alien sedimentologists aside, bombs still affect signature morphologic changes capable of lasting centuries — changes we preserve in historic parks and national monuments.

There’s a spherical-cow, back-of-the-envelope calculation to do here (Harte 1988). In total, approximately how much Earth-surface material has bombing moved since the technology appeared? I’m off to find an envelope. Maybe a flat mailer.

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