This month's Accretionary Wedge, hosted by the "Knowledge Flocs" Blog, asks for the interplay between geology and civilization - for example the interplay of warfare with the landscape. With the rapid development of war technology in the last 150 years also the impact of weapons on the landscape increased significantly. Arms, bombs and high energy explosives can displace large quantities of soil and bedrock in just few moments and form characteristic pits. These spurs in the landscape, formed by the activity of men, can be regarded as sort of ichnofossils characterizing the many battlefields of the 20th and 21th century (see also this paper by HUPY & SCHAETZL 2006).
In 1915 the First World War reached the - at the time - Austrian Dolomites, as the neutral Italy declared war to the Austrian-Hungarian Empire. The military high command feared that bypassing the Alps the Italian army could reach the capital city of Vienna in just one week, so it was decided to secure the most important routes and mountain passes in the region. One of these strategic locations was the 2.105m high Falzarego Pass, connecting the Valle del Boite with various other valleys of the Dolomites. This pass is overlooked by the nearly vertical cliffs of the small Lagazuoi, a 2.700m high mountain.
Fig.1. The Lagazuoi and the Falzarego Pass. The Austrian front line followed the crest of the mountain, the Italian soldiers were stationed in the valley floor.
There was no experience with war in such an extreme and alpine environment and it was almost impossible to attack the enemy when he took shelter above the steep cliffs of the Dolomites.
Fig.2. In response to the impossibility of direct attacks, soon the strategy of trench warfare was adopted in the Dolomites.
Fig.3. A machine gun nest in one of the excavated tunnels, overlooking the battlefield.
The strategists of the military tried to resolve this problem with a war technology successfully adopted in the soft shale, cretaceous sediments and quaternary deposits of the low plains of France, Netherlands or Russia: the Tunnel Warfare. At the end of long tunnels large quantities of explosives were detonated to form a breach in the front line of the enemy.
The Austrian army realized the importance to understand the geology of the battlefield and instituted a special division formed by "Kriegsgeologen" - war-geologists. These geologists recorded the geology along the front line and studied the best solutions for the construction of defense strategies, artificial tunnels and other military infrastructures. Apart their military duties they enjoyed great liberties and were allowed to move free at the front line and to collect samples of rocks and fossils for scientific purpose. Also in the Italian army many professional geologists could be found, even if the Italians never possessed an own military geologists-division.
In the Dolomites by undermining the position of the enemy or by causing rockfall on the enemy it was possible to misuse geology as sort of tactical weapon of mass destruction. In the years 1915 to 1917, when the war in the Dolomites ended, more than 34 blasting operations were attempted, 20 by the Italian army and 14 by the Austrian army.
In 1915, to reach the Italian position situated in middle of the southern cliff of the Lagazuoi, the Austrian army started to construct a tunnel on the northern slope of the mountain. Adopting a similar strategy the Italian soldiers tried to undermine the peak of the Lagazuoi, where the Austrian soldiers were stationed. The Lagazuoi is composed of the Cassian Dolomite-formation, a dolostone of a former Triassic reef complex with a massive reef core and tongues of reef debris interfingering with marls of an ancient sea basin. The hard dolostone is deformed and broken by tectonic forces. However the rock was much harder to excavate than expected, only with great effort in material and men it was possible to extend the tunnels by 10 meter every day.
The Austrian specialized soldier - a Kaiserjäger- Hanz Berger remembers the work in the tunnels:
"In the tunnels I'm afraid to be blasted into the air from below or to become entrapped, time seems to slow down in this place, …… a night can last forever and it seems that the sun is gone forever."
Shortly after midnight of the New Year's Day of 1916 the Austrian army initiated the "tunnel" wars in the Dolomites with the detonation of 300kg of explosives in a tunnel inside the Lagazuoi. A large boulder is blasted off but it causes only minor damage on the huts of the Italian front line.
July 11, 1916 the Italian army detonates 35.000kg of explosives hidden in a 400m long gallery behind the steep cliff of the Tofana di Roces, a mountain situated to the east of the Lagazuoi. Thirteen Austrian soldiers were killed by the avalanche of debris caused by the explosion.
Fig.4. The Tofana di Roces in the background. The mountain pass in the foreground is delimited by tectonic faults, looking from the uplifted mountain top of the Lagazuoi it's strategic advantageous position to control this access becomes clear.
January 14, 1917 the detonation of 16.000kg of explosives forms a 45 meter deep crater on the mountain top of the Lagazuoi - still today the debris cone formed this day is recognizable at the base of the cliff. Four months later (May 22) the Austrian Army detonates 30.400kg of explosives and causes a landslide of 200.000 cubic meters that kills four Italian soldiers. June 20, 1917 a second explosion below the mountain top of the Lagazoui forms a second debris cone at the base of the cliff.
The Italian soldier Luigi Panicalli recalls this day:
"I realize that in just some moments the results of all this months, in which we worked and suffered, will become visible. I'm like petrified. In these last moments my thoughts are by the enemy - poor guys - do they feel that death is approaching? Do they anticipate that their enemy is inside the mountain, ready to send them from the mountain into their graves?"
Fig.5. The scar in the cliff (light colored area just below the mountain top) and the debris cones produced from the explosions in 1917 are still well visible today at the Lagazuoi. A segment of the Italian front line was situated on the large ledge (in the middle of the picture) formed by a tectonic fault.
In the end the various attempts, operations and sacrifices of the soldiers along the front line of the Dolomites didn't significantly influence the progress of the First World War. Today still the scars in the landscape remain, as silent reminders of the madness of war.
AVANZINI, M. & ZAMBOTTO, P. (2009): Paleontologi in Guerra. PaleoItalia 20: 17-20
PIERO, G.; AVANZINI, M.; BREDA, A.; KUSTATSCHER, E.; PRETO, N.; ROGHI, G.; FURIN, S.; MASSARI, F. PICOTTI, V. & STEFANI, M. (2010): Dolomites 7th international Triassic Field Workshop Pan-European correlation of the Triassic. Field trip to the world heritage site of the Tethyan Triassic September 5-10, 2010 Dolomites, Southern Alps, Italy: 122
HUPY, J.P. & SCHAETZL, R.J. (2006): Introducing "bombturbation" a singular type of soil disturbance and mixing. Soil Science 171 (11) : 823-836
HUPY, J.P. & KOEHLER, T. (2012): Modern warfare as a significant form of zoogeomorphic disturbance upon the landscape. Geomorphology 157/158: 169-182