Popocatepetl Research Articles

Closing the Water: Ethnography of a Nahua Ritual

“Closing the water” is a ritual connected to the agrarian cycle and belongs to a set of rituals which are performed for the purpose of securing an abundant harvest of maize and other crops. This case study is based on fieldwork conducted by the author in Hueyapan, a Nahua community situated in the Highlands of Morelos on the southern slopes of the Popocatepetl volcano in Central Mexico. It consists of two parts: the first provides a description of the ritual; that is, it presents the ritual itself and the sequence of its parts. The second represents an analysis and explanation of the ritual from an anthropological point of view. Since the ritual of “Closing the water” belongs to a millennial tradition of Mesoamerica related to a ritual landscape, sacred mountains and agrarian cycle, the paper shows how this tradition and this ritual were incorporated into Catholicism in a process of religious syncretism.

New Insights into the Simulations of Electric Currents for Discharges and ULF Magnetic-Field Perturbations: Applications to the Popocatepetl Volcano and a Micro-Discharge Model

The noise-like behavior of geomagnetic anomalies observed in Tlamacas station (the Popocatepetl volcano, Mexico), linked to the ionization produced by intensive radon release, is presented in the experimental part of the study. The magnetic-field perturbations produced by electrical currents due to micro-discharges on the terrain irregularities are considered in a theoretical model. The simulations demonstrated that the discharge mechanism can generate perturbations with magnitudes of up to 1–10 nT in the ultra-low frequency (ULF)) range of 10−3–10−1 Hz. ULF Magnetic-field perturbations can be higher within storm-weather conditions under an accumulation of electric charges in clouds in the mountainous regions.

On the Radon-Related Mechanism of the Seismo- and Volcanogenic Geomagnetic Anomalies: Experiments in Tlamacas Mountain (Volcano Popocatepetl Area) and Electrode Effect Model

The noise-like behavior of the geomagnetic anomalies observed in Tlamacas station (volcano Popocatepetl, Mexico), linked to the ionization produced by intensive radon release, are presented in the experimental part of this study. The magnetic field perturbations produced by charge spreading currents within the fair-weather electric field are considered in the theoretical model based on the electrode. The electric charges are generated by the air ionization due to radon emanation. The simulations demonstrated that the ionization of the air leads to magnetic field perturbations of about 0.001–0.1 nT in the ULF (ultra low frequency) range 10−3–10−1 Hz. Magnetic field perturbations can be higher when the radon emanation occurs in a region with terrain irregularities.

Nipple Day

Nipple Day

Intergenerational transmission of historical memory of volcanic risk in Mexico

Collective memory is built on concepts and meanings that a population shares and builds over time. These contents are perpetuated through oral transmission from generation to generation. In the case of populations exposed to volcanic risk, coexistence with the volcano is part of their history and daily life. The present study focuses on understanding the meanings, perceptions, and responses facing (before and after) volcanic crises. All these are taken from the collective memory that has been transmitted intergenerationally after the new stage of activity of the Popocatepetl volcano in 1994. It was carried out with qualitative methodology, based on symbolic interactionism, integrating elements of ethnography and grounded theory. People of different age groups from a Mexican community near the Popocatepetl volcano participated. The techniques used were in-depth interviews, focus groups, and participant observation. The historical memory of the volcano’s activity before and after the last reactivation was reconstructed, thus evidencing the generational processes.

Recognition of the Airspace Affected by the Presence of Volcanic Ash from Popocatepetl Volcano Using Historical Satellite Images

A volcanic eruption can produce large ash clouds in the atmosphere around a volcano, affecting commercial aviation use of the airspace around the volcano. Encountering these ash clouds can cause severe damage to different parts of the aircraft, mainly the engines. This work seeks to contribute to the development of methods for observing the dispersion of volcanic ash and to complement computational methods that are currently used for the prediction of ash dispersion. The method presented here is based on the frequency of occurrence of the regions of airspace areas affected by ash emission during a volcanic eruption. Popocatepetl volcano, 60 km east of Mexico City is taken as a case study. A temporal wind analysis was carried out at different atmospheric levels, to identify the direction towards which the wind disperses ash at different times of the year. This information showed two different trends, related to seasons in the direction of dispersion: the first from November to May and the second from July to September. To identify the ash cloud and estimate its area, a set of 920 MODIS images that recorded Popocatepetl volcanic activity between 2000 and 2021 was used. These satellite images were subjected to a semi-automatic, digital pre-processing of binarization by thresholds, according to the level of the brightness temperature difference between band 31 (11 µm) and band 32 (12 µm), followed by manual evaluation of each binarized image. With the information obtained by the processing of the MODIS image, an information table was built with the geographical position of each pixel characterized by the presence of ash for each event. With these data, the areas around Popocatepetl volcano with the highest frequency of affectation by ash emissions were identified during the period analyzed. This study seeks to complement the results obtained by numerical models that make forecasts of ash dispersions and that are very important for the prevention of air navigation risks.

Unraveling the complex structure of popocatepetl volcano (Central Mexico): New evidence for collapse features and active faulting inferred from geophysical data

Popocatepetl volcano located in central Mexico has been erupting since December 1994 and since then many studies have been carried out in order to understand its eruptive behavior and assess the volcanic hazard since more than 25 million people are at risk. Nevertheless, few geophysical studies have been conducted in order to image the structure of the volcano. For this reason, we carried out magnetotelluric and gravity surveys on the northern flank of the volcano and also modeled magnetic data for the area. In this paper we provide new insight into the structure of the northern part of this complex volcanic structure, which is made up of several volcanoes that had been camouflaged by later pyroclastic deposits from recent eruptions. Results show major northwest-and northeast trending faults in the area that displaced blocks toward the south. These scarps are related to sector collapses. The oldest part of the complex, the Tlamacas volcano was identified by the discontinuities inferred from gravity, magnetic and magnetotelluric data. Electrical resistivity distribution also shows the existence of a lack of continuity in a conductive horizon on the eastern side of the prospected area, which coincides with the location of the hypocenter of the May 6, 2013 earthquake. This feature also corresponds to the position of Tlamacas Volcano and its late dome, that is also faulted, confirming that the NE-SW trending fault is still active. Faulting inferred from geophysical data and confirmed by the occurrence of earthquakes and vent alignment suggests the structural control on magma ascent and the weakness of the southeastern flank of the volcano.

Connectivity and hydrological efficiency dynamics at active volcanoes, Mexico

Connectivity is an emergent property that describes how complex topography favors or impedes sediment transfer processes. In active volcanic areas, high connectivity may lead to extremely efficient processes, such as lahars. The aim of the present study is to examine the behavior (activation–deactivation) of sub-basins affected by volcanic and anthropogenic processes by studying the changes in connectivity and hydrological efficiency. Two volcanic zones in Mexico were selected: Volcán de Colima and Popocatépetl volcano, the two most active and dangerous volcanoes in the country. The joint index of connectivity (ICJ) and lateral hydrological efficiency index (LHEI) were calculated for both volcanic areas in basins recently affected by eruptive activity (Volcán de Colima) and co-seismic landslides (Popocatépetl). The analyses enabled the identification of eleven recently activated sub-basins (3.82 km2) at the Volcán de Colima and fifteen (3.77 km2) at the Popocatepetl volcano, as a consequence of natural processes and economic activities. Critical thresholds indicating the percentage area of land cover/use at which a sub-basin reaches high or very high LHEI values and the percentage of land cover/use change required for a sub-basin to modify its behavior (activation–deactivation) were identified using classification trees. The holistic capacity of the concepts of connectivity and hydrological efficiency permits analyzing the spatiotemporal variations of sediment transport based on the interactions between the hydrogeomorphological dynamics of volcanic processes and the territorial impact of socio-economical activities. Through this approach, new active areas have been identified in both volcanoes; the knowledge of the processes that occurred in these areas represents a key factor for hazard and risk assessment for the population in the near future.

Domestication of aromatic medicinal plants in Mexico: Agastache (Lamiaceae)\u2014an ethnobotanical, morpho-physiological, and phytochemical analysis

BackgroundMost reports of domesticated plants that involve a domestication gradient or inter-specific hybridization in Mexico have focused on those used as food. This study provides knowledge about these processes in two aromatic medicinal plants, Agastache mexicana (Lamiaceae) and A. m. subsp. xolocotziana, widely used in Mexican traditional medicine for the treatment of gastrointestinal ailments and for their sedative effect. Different populations of A. mexicana along a gradient of domestication are found in the foothills of the Popocatepetl volcano of central Mexico, while in this same area the subsp. xolocotziana grows only in the cultivation, possibly a product of hybridization between A. mexicana and Agastache palmeri. This study links ethnobotanical, morpho-physiological, and phytochemical evidence to document the domestication of both taxa as well as elucidates the possible hybrid origin of the subsp. xolocotziana.MethodWe analyze three groups of data derived from (1) 80 semi-structured interviews aimed at documenting the selection criteria related to the use and management of A. mexicana; (2) a cultivation experiment under homogeneous conditions, evaluating 21 floral, vegetative, and seed characters (that were important according to ethnobotanical information) in 97 plants corresponding to 13 populations of the taxa under study; and (3) the chemical profiles of the essential oils of these plants by means of a thin-layer chromatography.ResultsBy linking the three types of evidence, two evolutionary processes are distinguished: (1) A. mexicana occurs in the encouraged-cultivated phases of the domestication gradient and (2) A. m. subsp. xolocotziana may have originated through inbreeding depression or hybridization. These two cultivated plants show a domestication syndrome based upon organoleptic differentiation due to their dissimilar phytochemical composition and gigantism in flowers, seeds, and rhizomes (the last enhancing their asexual reproductive capacity). In addition to this, A. mexicana exhibits more intense floral pigmentation and foliar gigantism while subsp. xolocotziana presents floral albinism and partial seed sterility.ConclusionTwo divergent evolutionary processes are reported for the domestication of A. mexicana as a result of the intensification of its use and management. The selection processes of these plants have resulted in alternation of the organoleptic properties based upon the divergence of the phytochemical composition. Also, gigantism has been selected in culturally preferred plant parts and in correlated structures. The preceding characteristics reinforce the joint use of these plants in infusion in Mexican traditionalmedicine for the treatment of gastrointestinal diseases and for their sedative effects.

A comprehensive paleomagnetic study from the last Plinian eruptions of Popocatepetl volcano: absolute chronology of lavas and estimation of emplacement temperatures of PDCs

Three lava flows (Buenavista, Xalitzintla and Nealtican) and pyroclastic density currents (Lorenzo and Pink Pumice) from two Popocatepetl Plinian eruptions were sampled for paleomagnetic dating. A detailed rock-magnetic characterization of the lavas, scoria clasts and pottery shards intercalated between the volcanic deposits was also carried out. Reliable results, both in direction and in intensity, were obtained for the Nealtican lava flow, which enabled its full-vector paleomagnetic dating using the archaeo_dating tool together with the global paleosecular variation model SHA.DIF.14 k, obtaining an age interval between 1040 AD and 1140 AD (95% probability confidence level), in good agreement with its associated 14C age. The well-grouped paleomagnetic direction of the seven specimens from two different scoria clasts of the Lorenzo Pumice pyroclastic density current suggests that clasts were emplaced hot, at a temperature that seems to have almost completely erased the original remanent magnetization of the clasts. This fact is supported by the reheating of the underlying pottery shards, evidenced as a clear secondary low-temperature range (room temperature to 350 °C) component at the orthogonal vector plots. Similarly, the three mean clusters directions obtained for site PO-2 (Pink Pumice)—roughly concentrated around the present geomagnetic field—suggest also a high emplacement temperature. Also, the first archeointensity dating of a pottery shard within the pyroclastic density current is reported. Finally, results of the rock-magnetic and paleomagnetic dating of the last Plinian eruptions from the Popocatepetl volcano, applied to different volcanic materials (lava and pyroclastic density currents), show the usefulness of these nonconventional and alternative techniques in the study of the eruptive activity of volcanoes.Graphic abstract.

Variability in the Gas Composition of the Popocatépetl Volcanic Plume

Long term time series of volcanic plumes composition constitute valuable indicators of the evolution of the magmatic and volcanic systems. We present here a 4 years long time series of molecular ratios of HF/HCl, HCl/SO2 , SiF4 /SO2 , HF/SiF4 measured in the Popocat epetl 's volcanic plume using ground-based solar absorption FTIR spectroscopy. The instrument based in the NDACC (Network for the Detection of Atmospheric Composition Change) station of Altzomoni site, facing the Popocatepetl volcano, provides an unrivalled precision. The computed mean and standard deviation of the HF/HCl and HCl/SO2 ratios for this period were found to be 0.24±0.03 and 0.11±0.03, respectively. SiF4 was detected in three occasions and the SiF4 /SO2 ratios ranged between (1.9±0.5) x 10e−3 and (9.9±0.4) x 10e−3. The HBr/HCl and HBr/SO2 ratios remained below their detection limit (1.25 x 10e−4 and 1.25 x 10e−5, respectively), given that a part of the HBr has already been converted to other bromine species (e.g.: BrO, Br2 ) a few kilometers downwind of the crater. Combining our time-series with satellite SO2 fluxes and seismic data, we explain the significant long-term HCl/SO2 variations by changes in the conduit and edifice permeabilities, impacting the deep and shallow degassing processes. The high temporal resolution of the data also allows capturing the variation of the volcanic plume composition preceding and induced by a common moderate explosion at Popocatepetl volcano. We interpret the observed variations of the HCl/SO2 ratio during the explosion as a progressive decompression and release of the gas (Taquet et al. 2017) stored in the deep conduit. SiF4 /HCl versus HF/HCl is found to have a linear relation with a slope of -1/4 during the explosions, which implies a conservation of fluorine.

Geomagnetic anomalies in the area of Popocatepetl volcano, Mexico

Geomagnetic anomalies of different nature observed in the area of Popocatepetl volcano are presented and analyzed in the current paper. The analysis reveals some anomalies considered to be of local volcanic origin: the EM background in the vicinity of the volcano was found to be significantly noisier than other reference stations; sporadic strong noise-like geomagnetic activity was observed in the H component; some geomagnetic pulsations were observed only at Tlamacas station (located 4 km near the volcano). Some noticeable changes in the evolution of the fractal index calculated for geomagnetic field may be connected to the presence of critical processes in the volcano dynamics.

Breathing and Coughing: The Extraordinarily High Degassing of Popocatépetl Volcano Investigated With an SO2 Camera

How do lava domes release volcanic gases? Studying this problem is crucial to understand, and potentially anticipate, the generation of the sudden and dangerous explosive eruptions that frequently accompany dome extrusions. Since its awakening in 1994, Popocatepetl volcano has produced more than fifty lava domes and has been consistently among the strongest permanent emitters of volcanic gases. In this work, we have characterized the passive and explosive degassing between 2013 and 2016 at a high time resolution using an SO2 camera, to achieve a better understanding of the conduit processes. Our 4-year average SO2 flux is 45 kg/s, in line with the long-term average of the whole current eruptive period. We show that Popocatepetl volcano is essentially an open system and that passive degassing, i.e. degassing with no associated emission of lava or ash, dominates >95% of the time. This passive degassing is continuous and sustained, whether the crater contains a lava dome or not. It shows most of the time a strong periodic component, with a pseudo-period of ~5 minutes, and amplitudes of 30 to 60% of the average value. We could distinguish two types of explosions based on their SO2 flux patterns. The first type (E1) occurs in the middle of the normal passive degassing and is followed by a rapid return of the SO2 flux down to its pre-explosive level. The second type (E2), which corresponds to the strongest events, is anticipated by a rapid decrease of the SO2 flux to abnormally low values and is followed by a return to its normal values. The E2 explosions are probably caused by the accumulation of gas below a rapidly compacting permeable dome. We suggest that transient episodes of gravitational compaction of the usually permeable dome and the upper conduit is the only mechanism that is fast enough to explain the sharp decrease of the SO2 flux that anticipates the E2 explosions. Our model is potentially applicable to a large number of andesitic volcanoes that undergo passive degassing interspersed with short-lived explosions.

Trends of climate change indices in some Mexican cities from 1980 to 2010

Global studies focusing on climate extremes in urban areas, specifically in Mexico, have not been approached with a sufficient level of detail, despite considerably increased risks for both infrastructure and human society. Based on 14 climate indices proposed by the Expert Team on Climate Change Detection and Indices (ETCCDI) and the application of the nonparametric Mann-Kendall and Sen’s slope tests, the observed trends of climate extremes in 16 urban areas in Mexico from 1980 to 2010 were analyzed. The results show that climate conditions over most cities of Mexico are changing, as indicated by a warming trend during the study period. Significant increases were detected in the annual average maximum temperature (TMX) and the annual average minimum temperature (TMN). There is no clear trend that the warmest days (TXx) are increasing, but the annual number of warm days (TX90p) and summer days (SU) has increased, and the cold days (TX10p) have decreased. Associated with these changes are concomitant decreases in fewer coldest nights (TNn), an increase in the percentage of days with warm nights (TN90p) and tropical nights (TR), and a decrease in the number of frost days (FD). In contrast, the analysis reveals a statistically significant decrease in the mean temperature and the amount of warm days in Mexico City, which could be associated with the increasing trend of atmospheric pollution and the continuous smoke and ash emissions from the volcano Popocatepetl, which disperse incoming solar radiation and reduce radiative forcing. Climate change indices based on daily precipitation data show positive trends in many cities. In general, an increasing trend in very wet days (R95p), a number of very heavy rainfall days ≥ 25 mm (R25), and the annual total wet days (PRCP) were observed. These results highlight the vulnerability of cities confronted with both global and local climate change and the importance of promoting effective local risk reduction measures as part of urban planning for city dwellers.

Metal concentrations in recent ash fall of Popocatepetl volcano 2016, Central Mexico: Is human health at risk?

The present study addresses the metal concentration pattern and associated human health risks in ash samples of Popocatepetl volcano. In this regard, 12 ash samples from different regions of Puebla City were collected and analyzed for 28 major and trace metals, out of which exclusively 8 metals of potential risk (Cd, Co, Cr, Cu, Mn, Ni, Pb & Zn) were selected for human health risk validation. The metal concentration pattern showed an enriching trend for ferromagnesium and carbonate elements compared to previous ash eruptions. Enrichment factor and geoaccumulation indices displayed a least significant enhancement of metals from baseline concentrations. More likely, the potential ecological risk index suggested no harmful biological effects due to the presence of these metals in ash. Concurrently, in the human health risk assessment model, the hazard quotient and hazard index values < 1 indicated safe levels and no carcinogenic effects. All-inclusive, this study highlights the context of metals in ash fall of Popocatepetl which presents no adverse effects over the human population.

Narrativas populares sobre desastres. El caso de Amecameca ante el riesgo volcánico del Popocatépetl

There are different speeches and practices told by people and government on an important public policy issue such as civil protection. First, in this paper, the notion of risk, according to Social Sciences is reviewed, as well as the civil protection policies. Secondly, the look around the risk around Popocatepetl volcano in Amecameca and some popular narratives that present some distance from the technical scientific discourse are remarked. This is done through some data and results from a survey applied in this place and interviews that were done among the population. The results indicate it is possible to see the distance between theexpressions, glances and speeches regarding the volcano risk.

A new method of simulating volcanic eruption column formation and dispersion of ejected ash clouds

ABSTRACTA new Eulerian−Lagrangian model is developed to predict the formation of eruption columns, and the long range transport and dispersion of volcanic ash clouds in the atmosphere. The model capability is tested by presenting the atmospheric dispersion of ash clouds released during two eruptions of the Popocatepetl volcano in Mexico. The atmospheric wind predictions were made by using the Eulerian regional atmospheric modelling system (RAMS), which is well tested over the Mexico region. Two Lagrangian models were also employed: (1) an eruption column formation model and (2) a Lagrangian stochastic deterministic (LSD) particle dispersion model. In a LSD model, the continuous plume is simulated by several puffs (clouds) successively released in the atmosphere. (1) The influence of the wind on the eruption column, (2) the transport and dispersion of the ash cloud and (3) the concentration of volcanic ash using a smoothed particle hydrodynamics technique are reported. This is thought to be a unique combination of mathematical prediction models and would be of interest to the broader scientific community. The formation of the eruption column is compared with ground observations, while the long range trajectory of the ash clouds is compared with images based on satellite data, qualitatively. In both cases the agreement within the observed and simulated plume shape was found to be satisfactory which indicated the suitability of the Eulerian wind prediction model (RAMS) in the region as well as that of Lagrangian models employed in the study.

Automated detection and characterization of harmonic tremor in continuous seismic data

AbstractHarmonic tremor is a common feature of volcanic, hydrothermal, and ice sheet seismicity and is thus an important proxy for monitoring changes in these systems. However, no automated methods for detecting harmonic tremor currently exist. Because harmonic tremor shares characteristics with speech and music, digital signal processing techniques for analyzing these signals can be adapted. I develop a novel pitch‐detection‐based algorithm to automatically identify occurrences of harmonic tremor and characterize their frequency content. The algorithm is applied to seismic data from Popocatepetl Volcano, Mexico, and benchmarked against a monthlong manually detected catalog of harmonic tremor events. During a period of heightened eruptive activity from December 2014 to May 2015, the algorithm detects 1465 min of harmonic tremor, which generally precede periods of heightened explosive activity. These results demonstrate the algorithm's ability to accurately characterize harmonic tremor while highlighting the need for additional work to understand its causes and implications at restless volcanoes.

Characterizing volcanic states at Popocatepetl, Mexico by informational analysis of continuous geomagnetic signal

The investigation of the dynamics of the continuous geomagnetic signal recorded at Popocatepetl volcano from 1997 to 1999 was performed using the Fisher–Shannon approach, a statistical tool for identifying dynamic changes in complex systems. Our results reveal that dynamic changes in the Total Magnetic Field (TMF) are correlated with different stress states of the magmatic setting and the plumbing system in the volcano. The results contribute to reveal the probable signatures of the thermal processes involved in the movement of the magma that induce the variations of the TMF signal.

Statistical analysis of the sustained lava dome emplacement and destruction processes at Popocatépetl volcano, Central México

Popocatepetl volcano reawakened in 1994 after nearly 70 years of quiescence. Between 1996 and 2015, a succession of at least 38 lava domes have been irregularly emplaced and destroyed, with each dome reaching particular volumes at specific emplacement rates. The complexity of this sequence is analyzed using statistical methods in an attempt to gain insight into the physics and dynamics of the lava dome emplacement and destruction process and to objectively assess the hazards related to that volcano. The time series of emplacements, dome residences, lava effusion lulls, and emplaced dome volumes and thicknesses are modeled using the simple exponential and Weibull distributions, the compound non-homogeneous generalized Pareto–Poisson process (NHPPP), and the mixture of exponentials distribution (MOED). The statistical analysis reveals that the sequence of dome emplacements is a non-stationary, self-regulating process most likely controlled by the balance between buoyancy-driven magma ascent and volatile exsolution crystallization. This balance has supported the sustained effusive activity for decades and may persist for an undetermined amount of time. However, the eruptive history of Popocatepetl includes major Plinian phases that may have resulted from a breach in that balance. Certain criteria to recognize such breaching conditions are inferred from this statistical analysis.