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A Tale of Two Seismic Cities: How Memory Prevents Disaster

By Amanda Gaggioli


In this essay, Multi-Country Research Fellowship alumnus, Amanda Gaggioli, discusses her research on long-term human-earthquake relationships of resilience through examples of earthquakes in the Greco-Roman world and the San Francisco earthquake of April 18, 1906. Amanda carried out her fellowship in affiliation with the Cyprus American Archaeological Research Institute (CAARI) and the American School of Classical Studies at Athens (ASCSA).

Map of Helike, Greece and San Francisco, California

This morning, a group of early bird San Franciscans gathered around Lotta Fountain – the meeting point in the immediate aftermath of an earthquake 117 years ago. At 5:12 AM, the exact time of the 1906 earthquake, sirens rang throughout the city. City officials led the crowd in a procession, while dramatically recounting the destruction and lives lost in 1906.


At the corner of Church and 20th Streets sits the fire hydrant famed for saving the Mission District from burning in the fires that accompanied the earthquake. Procession attendees sprayed the fire hydrant gold, while speaking about family, friends, or places for their commemoration or future protection.


The most effective, but often overlooked, strategy for disaster prevention, or resilience, is that of memory. This annual ritual procession commits to memory the 1906 earthquake. It reminds the San Francisco community that the next ‘big one’ is coming. The question just remains a matter of when.


For the Greek philosopher Aristotle, discrepancies between human lifespans and the drawn out timescale and cycles of environmental change cause human cultures to repeatedly develop and forget adaptive technologies. Over time, memories of environmental hazards’ potential to disrupt human lives and livelihoods are lost.


This is the paradox of earthquake disasters. With each day that passes, we are one day closer to the ‘big one’ but we are also one day closer to forgetting. A reflection on the broader human experience of earthquakes and disasters across time and space can help to further prevent suffering from this memory loss.

About two months ago, on February 6, 2023, a 7.8 magnitude (Mw) earthquake on the boundary of earth’s major Eurasian, African, and Arabian tectonic plates resulted in disastrous levels of death and destruction in Turkey and Syria — a bleak reminder that the Mediterranean region, particularly the Aegean and eastern Mediterranean, is one of the most seismically active regions of the world. Given the high seismic setting and availability of vast historical sources – both material and textual – the ancient Mediterranean offers perhaps the best source into long-term dynamics of human relationships with earthquakes, disaster, and memory.


As a former PhD student at Stanford University, the legacies of the 1906 event and seismic culture of the Bay Area informed my dissertation Earthquakes and the Structuring of Greco-Roman Society supported by the CAORC Multi-Country Research Fellowship. Everywhere you look, the materiality of a seismic culture manifests on Stanford’s campus.


Stanford Memorial Church inscription. Photo Credit: Matthew Previto

Building inscriptions on campus mark post-1906 restorations. Anti-seismic steel frames reinforce concrete in building reconstructions. These materials were also engineered to match the original and aesthetically desired yellowish orange sandstone of the Romanesque and Missional Revival architectural style. Stanford’s monumental ‘Stone River’ built from 128 tons of this collapsed sandstone building debris from the 1906, and later 1989, earthquake symbolizes and memorializes these types of ongoing, dynamic relationships between the human-built and geological environments.



Stanford's 'Stone River' monument

Memory is the prerequisite for resilience. But the material choices that enhance earthquake resilience also involve considerations of environmental conditions together with cultural values.


In the world of ancient Greece and Rome, the memory of earthquakes extended across generations. The most well-known event in the Greco-Roman world was the 373 BC earthquake at Helike located in the northwest Peloponnese of Greece on the coast of the Gulf of Corinth. Cultural memory of the 373 BC event influenced Greco-Roman earthquake perceptions for nearly 1000 years and in removed places. The 373 BCE earthquake, just as the 1906 event, became the touchstone for seismic risks.


Amanda at the site of Hellenistic Helike. Photo Credit: Dora Katsonopoulou

Several Greco-Romans recount the 373 BC event at Helike at times when earthquakes struck other areas of the Mediterranean. Greco-Romans remembered this event in terms of the earthquake and associated tidal wave and flooding that brought widespread death and destruction. The submerged underwater ruins captured an indelible cultural memory and imagination.


They described how the people of Helike disrespected Poseidon. As punishment, the god with dualistic powers to both destroy and also protect the human-built environment struck Helike with an earthquake and tsunami that killed many people and left the city ruined and submerged.


Today, it is commonly accepted that the convergence and sliding of faults cause earthquakes. In the Greco-Roman world, some understood that Poseidon, nicknamed Earthshaker, embodied these seismic forces. Greco-Romans were wary of upsetting the gods, but particularly Poseidon, because his wrath might bring a deadly and destructive earthquake. In response to both small earthquake tremors and high magnitude events, Greco-Romans performed rituals, especially in honor of Poseidon, to reinforce memory and prevent disaster.


The regions of Helike and the San Francisco Bay experience similar earthquake hazards. Memory in both places has played an important role in the dynamic relationships between the material requirements for urban living, environmental change, and disaster through time.


My fieldwork in Helike supported by CAORC revealed long-term human-earthquake relationships of resilience. The geography of Helike resembles that of the Bay Area. The Corinthian Gulf has approximately the same size and dimensions as the San Francisco Bay. Its length; however, runs east-west, rather than north-south. Several seismic faults run through the region oriented parallel to the gulf, including the rapidly extending Corinthian Gulf Rift and Helike and Aigio faults, similar to the San Andreas, Hayward, and other faults running north-south in the Bay Area.

Amanda satanding under the Helike Fault. Photo Credit: Mariza Kormann

I collected and analyzed soils and associated settlement architecture from excavations of settlement sites belonging to occupation phases spanning the third millennium BCE to fifth century CE within the 15 km2 delta plain of Helike. The integration of historical, geomorphological, micromorphological, paleoseismological, FTIR, and architectural data showed the interrelations of earthquake deformation and other environmental changes, such as flooding and rapid coastal change, and engineering in the human-built environment.


There is a general repeated observation of north-south destructions to wall foundations and floors and also innovation and invention in wall partitions and foundations to prevent north-south destructions to walls that is consistent through time. Destruction, innovation, and invention is related to the south to north dipping of the Helike fault, south to north alluvial and fluvial deposition, and south to north gentle slope of the plain.


More importantly, these architectural types are directly, i.e. stratigraphically, associated with seismically triggered soft sediment deformation, particularly their south to north sloping formation patterns. Most are familiar that earthquakes occur on faults and cause ruptures on faults. Earthquakes also leave marks that stay in soils and sediments forever and are visible in stratigraphy on the micro-scale, offering an additional and essential source of earthquake memory.


​​Differences in the implementation and material manifestations of north-south destructions and also innovation and invention to prevent north-south destructions reveal that choices in the human-built environment are not simple functional adaptations to perceived environmental problems. Resilient choices are also conditioned by broader political leadership and organization, economic resources and production, and cultural values. Earthquakes traditionally perceived as ‘natural’ disasters implicated in collapse and catastrophe are not ‘natural’ but social phenomena and a critical factor in political, economic, and cultural developments.

Amanda doing soil micromorphology analysis at the Wiener Lab of the American School of Classical Studies Athens

Memory of earthquake destruction to human-built structures has encouraged engineering solutions to not only rebuild cities to their previous state but also improve them. Greco-Romans built with a view towards Poseidon Earthshaker and seismic forces. Poseidon himself built superior structures, including his own house described as indestructible and imperishable. Ancient writers detailed the effects of seismic forces on buildings. Some understood that flexible construction techniques, such as timber-framing for walls and foundations of buildings, could better withstand seismic shaking.


In the aftermath of 1906, including on Stanford’s campus, similar types of flexible skeleton-framed buildings of steel had survived and were constructed for resisting future earthquakes. Since 1906, research in anti-seismic engineering has boomed in the Bay Area with aims to prepare for the inevitable ‘big one.’


The memory of the earthquake disaster at Helike, just as in San Francisco, also encouraged advancements in seismology. Aristotle, a contemporary of the 373 BCE event, offered field observations from the region of Helike that contributed to his proposition that winds are the elemental cause of earthquakes — a predominant ‘scientific’ theory on earthquakes in the Greco-Roman world. After 1906, field observations of a 470 km long surface break along the San Andreas Fault helped seismologists establish the association of earthquakes with fault movements – the current predominant scientific explanation.

Amanda speaking oabout her research at the International Conference on Helike VI in Aigio, Greece. Photo Credit: Ioannis Drougoutis

Memory plays a key role in resilience by inspiring and reinforcing new and old ways of effectively living with environmental change. Even though the lived experience of the 1906 earthquake disaster is lost, the memory of it is still very much alive. Because of this memory, a seismic culture exists: in our scientific recording, understanding, and communication of geophysical processes and hazards, building techniques and codes, and safety regulations and drills in the region. With the Greco-Romans, we catch a glimpse of a broader common human experience with earthquakes, disasters, and resilience across time and space. This deeper collective memory further equips us to face persistent and inevitable environmental change and hazards.

 

Amanda Gaggioli is a Postdoctoral Research Associate at the Joukowsky Institute for Archaeology & the Ancient World at Brown University. Her research includes interdisciplinary approaches that combine ancient textual, archaeological, and natural scientific approaches to past human-geological environmental relationships, in particular earthquakes and associated seismic phenomena, in the eastern Mediterranean.

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