Using tree-ring analysis to evaluate intra-eruptive lahar activity in the Nexpayantla Gorge, Popocatépetl volcano (central Mexico)

Modelling the 2012 Lahar in a Sector of Jamapa Gorge (Pico de Orizaba Volcano, Mexico) Using RAMMS and Tree-Ring Evidence

“…The intra-annual dating of 19 scars found in trees ( Figures 3B) indicate that the lahar event must have taken place in early latewood which locally corresponds to late summer ( Figure 5); this timing is consistent with the passage of hurricane "Ernesto" on 9 August 2012 at the study site. Evidence of lahars triggered by the 2012 hurricane can be found elsewhere in central Mexico, namely on Popocatépetl [20]; Iztaccíhuatl [78] and La Malinche [41] volcanoes. The timing of the 2012 lahar at our study site is further supported by evidence from local newspapers [79].…”

“…In Mexico, dendrogeomorphic approaches have been used to date and reconstruct lahars [18][19][20] and debris flows [21,41] in the past. By contrast, studies focusing on the magnitude of hydrogeomorphic events are still critically lacking.…”

“…In addition to the dating of scars to the year [45,46], we also aimed to identify the seasonal timing of lahars based on the position of growth anomalies (i.e., injuries and callus tissue) within the tree ring according to Stoffel et al [72]. The growing season was adapted to central Mexico conifers [20].…”

“…Different approaches have been used in the past to understand the occurrence and triggering of lahars. Past work included rainfall-runout analyses [8,11,[13][14][15], real-time monitoring of lahars with rainfall, seismic (geophones) and observational data [16,17], but also analyses of disturbances recorded in tree-ring series [18][19][20][21].…”

“…Furthermore, historical records of volcanic or geomorphic events are not generally available, especially in areas with limited population densities. In this context, the reconstruction of past events with tree-ring series can contribute significantly to an improved knowledge of the frequency and/or magnitude of past volcanic or geomorphic processes [19][20][21]42]. Hence, scarred trees have proven very useful for the dating and frequency analysis of past geomorphic events [43] and for the determination of paleostage indicators (PSI; [39]) as the level of scars on trees is considered to indicate the minimum flood level during a given event [44].…”