Late Formative Flooding of Izapa After an Eruption of Tacaná Volcano

Abstract

Between the years of 30 b.c. to a.d. 80, during the Late Formative period, the site of Izapa was flooded by lahars associated with an explosive eruption of the San Antonio volcano (part of the Tacaná Volcanic Complex). Computer simulations suggest that hot pyroclastic flows did not impact Izapa directly, but did impact the region considerably, filling and clogging the Cahuacan and Mixcun rivers with hot debris. The material was quickly saturated by heavy rains and, as the water from the rivers overtopped the obstruction, remobilized in the form of a hot mixture of mud and water known as a lahar (or flood of volcanic origin), which flowed down through the piedmont zone along the Cahuacan, Mixcun-Suchiate, and Izapa rivers. At Izapa, the flood took the form of a 6-m catastrophic wave of mud and water that likely destroyed crops and caused many causalities, surrounding the architectural mounds at Izapa with a muddy landscape. The floods also dramatically affected the rivers downstream, undoubtedly wreaking serious damage to the transport and trade of goods along the coast.

Captive Representations and Social Discourse at Izapa and in Late Formative Southeastern Mesoamerica

“…In this essay, I refer to Izapa sculpture as Late Formative in date, in keeping with Lowe et al's (1982) assignation of most of the monuments to the Guillén phase, now dated to 300–100 cal b.c. (Lowe et al 2013:Figure 2), as well as more recent archaeological and environmental data presented in this special section by Macías et al (2018), Mendelsohn et al (2018), and Rosenswig et al (2018). Yet, I do so with the caveat that the specific chronological placement of the extensive Izapa corpus, as well as monuments carved in the “Izapan style” at other sites (see Guernsey [2006:43–73] for discussion of the history and problematic nature of this designation), remains a subject of ongoing investigation and debate (Inomata and Henderson 2016; Inomata et al 2014).…”

Effects of hurricanes, mudslides, flooding, and riverine erosion on the erasure of archaeological sites in tropical, highland Honduras

“…In addition to heavy rainfall from storms, volcanic eruptions, and earthquakes have the potential to trigger tremors and landslides that transformed the landscape over other parts of the Central American highlands (Sheets & Grayson, ). Major mudflows and floods also cannibalize previous events, which explains why finds of sites impacted by debris flows and mudflows are so seldom documented in Central America in areas remote from volcanoes (but see Macías et al, ).…”

“…The answer is dependent on the particular geology and geomorphology of the valleys explored, especially in terms of their closeness to landslide prone hillsides, susceptibility to large‐scale flooding and/or the proximity of additional catastrophic sources like volcanoes that cause lahars, volcanic flows, and ashfalls. For example, lahars deposited volcanic material up to 30 km away from the Tacana volcano (Macías et al ). Also, Ashmore (2008) encountered few visible sites in the areas immediately surrounding Quirigua in the Motagua River valley, due to deposition of river sediments estimated to have accumulated at a rate of 18–22 cm per 100 years.…”

“…(Sheets & Grayson, 2013). Major mudflows and floods also cannibalize previous events, which explains why finds of sites impacted by debris flows and mudflows are so seldom documented in Central America in areas remote from volcanoes (but see Macías et al, 2018).…”

“…The Illopango eruption in El Salvador blanketed parts of western El Salvador under meters of volcanic ash in the Early Classic period (A.D. 400–600; Sheets & Grayson, ). Lahars or landslides caused when gas pyroclastics and water rush down the slopes of volcanoes, have also buried remains ranging from early hominins in Olduvai gorge (Stanistreet et al, ), Herculaneum (De Carolis & Patricelli, ), and at the sites of Cholula (Sheets & Grayson, ) and Izapa in Mesoamerica (Macías, Arce, Capra, Saucedo, & Sanchez‐Nuñez, ). However, other nonvolcanic catastrophic processes also have a history of impact on the visibility of archaeological remains in highland Central America.…”