Use Of Volcanic Ash Research Articles

Etna volcanic ash as new sustainable supplementary cementitious material

The use of supplementary cementitious materials (SCMs) is one of the fundamental pillars in the transition towards sustainable binders, and the seek for new alternative SCMs is becoming more and more important to front, on one hand, the increased request, and the expected future shortage of some existing SCMs, such as blast furnace and steel slag, on the other. In this work the use of volcanic ash as a pozzolanic constituent in the manufacture of a type IV mixed cement has been explored. Thousands of tons of ash are erupted for each Strombolian event from the volcano Etna (Italy) . The periodicity and magnitude of the events is variable but very often impressive. In the year 2021 alone, 51 significant paroxysmal events occurred. The enormous quantities of material removed from urbanized areas constitute a valuable resource that can be reused instead of being disposed of as waste. The experimental results of the tests carried out for the physical, mechanical and chemical characterization of the new mixed cement showed that the volcanic material meets the requirements dictated by the standard EN 196-5 to assess pozzolanic properties, and can be effectively used in the production of commercial pozzolanic cements as a partial, or even total replacement for the natural pozzolans. These findings are fundamental to encourage the start-up of a production chain aimed at recycling the waste eruptive material of volcanoes that insist on urbanized areas. Moreover, a review of the regulative framework concerning test methods assessing the pozzolanicity of volcanic material is given.

Penggunaan Kapur Tohor dan Abu Vulkanik pada Bata Ringan Terhadap Berat Jenis, Daya Serap Air, dan Kuat Tekan

Light brick is a material commonly used in building walls besides red brick. Quick lime and volcanic ash were used in this research as substitute materials for making CLC lightweight bricks. This research aims to analyze using quicklime as a cement substitute and volcanic ash as a sand substitute to test density, water absorption capacity, and compressive strength. Light brick testing refers to the SNI standards for wall masonry. This research also compares the production costs of substitute lightweight bricks with conventional ones. The method used is quantitative experimentation and data analysis techniques using regression analysis. The influencing variable in this research is the independent variable, namely the use of volcanic ash: quicklime in variation A 0%: 0%, variation B 9%: 15%, variation C 9%: 30%, and variation D 9%: 45%. Based on the test results, it can be concluded that using volcanic ash affects increasing density and compressive strength and reduces the value of water absorption capacity. The optimum test results were in Variation D with an average density value of 956 kg/m3, water absorption value of 17%, and compressive strength value of 2.08 MPa.

Experimental Research on Anti-freezing and Thawing Performance of Basalt Fiber Reinforced Fly Ash Concrete in the Corrosive Conditions

Basalt fiber reinforced fly ash concrete (BFRFAC) is a new inorganic nonmetal composite construction material with excellent mechanical properties that could be widely used for bridge floors, pavements, and other construction engineering projects. The anti-freezing and thawing performance of BFRFAC in the corrosion circumstances was studied in detail with a comparison to normal concrete (NC) by using quick freezing method in this work. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the experimental group, the RDME on BFRFAC were determined in chloride corrosion, sulfate corrosion, the complex combined corrosion of chloride and sulfate solution. Further, a scanning electron microscope (SEM) was employed to scan the meso-structure of the rupture cross-section in t-he composite material at magnifications of 500, 1000, and 1500. The gripping effect between basalt fibers and su-bstrate was quantitatively analyzed in the case of pull-out failure and fracture failure, which convincingly reveal-ed the crack resistance, reinforcement, and toughening mechanisms of basalt fibers on concrete substrate. We found that RDME decreased and its descent rate slows down when BFRFAC was exposed to freeze-thaw cycles in above-mentioned four situations. The number of freeze-thaw cycles of BFRFAC was greater than 400 in the complex case of solution corrosion. The BFRFAC cyclic lifespan could be effectively extended in contrast to NC. Moreover, make full use of volcanic ash and micro-aggregate effect of fly ash can improves the gripping effect between basalt fibers and concrete substrate. As a result, it has the potential to significantly improve anti-freezing and thawing damage capacity of BFRFAC.

Carbon nanofiber dispersion in alkali solution and its reinforcement of alkali-activated volcanic ash-based geopolymers

Volcanic ash has several negative impacts on the environment and can be used in massive to synthesize geopolymers, which are considered quasi-brittle. Carbon nanofibers (CNFs) can reinforce the geopolymers, and the dispersion of CNFs directly determines the reinforcement effect. However, the dispersion of CNFs in alkali solutions is challenging. In this paper, the effect of surfactant type, dosage, and ultrasonic time on CNFs dispersion in aqueous and alkali solutions was investigated by the quantitive method of microscopic image processing to determine the preferred dispersion scheme. Zeta potential tests and visual observation were used to analyze the mechanism and stability. Based on this, volcanic ash-based geopolymer nanocomposites with 0.1 wt% contents of CNFs were synthesized. The mechanical properties were tested, and the microstructure was characterized using Scanning Electron Microscope coupled with Energy Dispersive Spectroscopy and Mercury Intrusion Porosimetry. The results showed that methylcellulose (MC), polycarboxylate superplasticizer (PC), and polyvinylpyrrolidone (PVP) could disperse CNFs in aqueous, but evident aggregations can be observed in the alkali solution. PC performed better than MC and PVP in alkali solutions, with 4.83% aggregation area of the whole image, 86% of 0–100 μm2 aggregations, and an average aggregation area of 87 μm2, beneficial from the comb-like structures. Dispersed CNFs can improve the 28-d flexural and compressive strength of the resulting geopolymer nanocomposite by 23% and 16%, respectively, and refine the pore structure through filling, bridging, and nucleation effects, decreasing the average pore size and porosity by 33% and 15%. This paper will contribute to the resourceful use of volcanic ash to reduce pollution and the higher reinforcement of CNFs in alkali-activated geopolymers.

Preliminary research results on the use of volcanic ash and felsic volcanic rock in Vietnam as materials to support crop growth

As we know, vascular plants (Tracheophyta) in general and crop plants require a defined amount of trace elements to ensure normal growth and development. In many developed countries, some natural materials have been used as an addition for growing ornamental plants, vegetables, and hydroculture plants. In Vietnam, natural minerals to support plant growth is still very limited. Meanwhile, the source of raw materials in the territory of Vietnam is quite popular, so the research and experiments using Vietnamese volcanic ash and felsic volcanic rocks as improving materials for plant growing is important and very necessary work. Analytical methods such as Ronghen Fluorescence (XRF), Mass Spectrometry (ICP-MS), Scanning electron microscopy (SEM) and calcination at 6500C, 7500C, and 9000C have been used to determine the composition of felsic tuff samples belonging to the Don Duong Formation (PY19) and mafic ash samples of the Dai Nga Formation (KR2/2). In addition, control sample matching method was also used in the research process to evaluate the growth plants. The experiment materials (raw samples and calcined samples at 9000C) were mixed with the soil for planting (in different proportions); two types of plants, named Caviar Cockatio (Chicken Crest Vegetables) and Amaranth Asiatica (Purple Amaranth), were selected for experimenting. In general, both Caviar Cockatio and Amaranth Asiatica developed quicker when grew on a ground of soil mixed with the experiment material. The plant’s growth rate depends on the type of material (unbaked, calcined), support material content, plant type and stage of growth. Primary research results show that volcanic materials in Vietnam can support the growth of plants.

Potential Use of Volcanic Ash as Filler Material in Hot Mix Asphalt

Road construction often focuses on the use of conventional materials. Due to the depletion of these conventional materials, this cannot be always true. To overcome such problems, several alternative construction materials have been proposed as sustainable solutions. Thus, this study has investigated the potential use of volcanic ash (VA) as an alternative filler material in hot mix asphalt. The investigation has used laboratory scale and purposive sampling method for sample collection. The plastic index and specific gravity of volcano ash are 0.92% and 2.44, respectively. The chemical composition analysis indicated that VA is a class‐N pozzolana material. Maximum stability of 11.38 kN was obtained at full replacement of volcano ash. The tensile strength ratio of the mix at full replacement of CSD and volcanic ash is 82% and 98%, respectively. From the fatigue resistance analysis, the probable failure of pavement constructed with the mixture containing VA could be improved from 16600 to 14400. Due to its rough surface, VA has better bonding ability with bitumen compared to CSD. The mix prepared from VA has less deformation tendency than that prepared from CSD.

Resistance of Alkali-Activated Blended Volcanic Ash-MSWI-FA Mortar in Sulphuric Acid and Artificial Seawater

This paper investigates the resistance of alkali-activated binder from volcanic ash (VA) + Municipal Solid Waste Incinerator Fly Ash (MSWI-FA) system exposed into sulphuric acid solution and artificial seawater at 56 days. The effect of these aggressive media on the physical, structural, mechanical and microstructural properties of alkali-activated mortars was discussed. The degradation was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The decrease of compressive strength after 56 days was 9.10%, 22.08%, 32.5% in artificial seawater, 2% H2SO4 and 4% H2SO4, respectively. The loss of strength in both media is primarily due to the fact that the water molecules present in these media penetrated into the pore cavities between binders and aggregates, making them weak. In an acidic medium, it is also due to the decalcification and depolymerization reactions whereas in seawater medium, it is attributed to the movement of content ions and probable formation of Friedel’s salt. The results disclose that VA + MSWI-FA based alkali activated materials resist better in seawater than in sulphuric acid solution. Synergistic use of volcanic ash and MSWI-FA for construction materials through alkaline activation looks like the upcoming trend to valorize these wastes.

The Effectiveness Of Providing Vulanic Ash (Tuff Vulcan) And Dolomite As Amelioran Materials On The Growth Of Immature Liberica Coffee Plants In Peat Land Of Mekar Jaya Village

Liberika coffee is one type of coffee that is widely cultivated by people in wetland areas (peat) precisely in Betara District, Tanjung Jabung Barat Regency. In recent years, this district has become a development center and provider of Liberika coffee seeds for coffee plantation farmers from various regions such as Palembang, Kalimantan and Riau. Liberika coffee is a type of coffee that is able to adapt and produce quite well in peatlands with areca nut as a cover crop. The productivity of coffee in this area is still low at an average of 715 / kg when compared to the potential yield of Liberika coffee which can reach 950 kg / ha. Increasing production and productivity can be done through intensification and extensification. One of the efforts to improve the physical and chemical properties of peat soils so as to increase the growth and production of coffee plants is the use of ameliorants (soil enhancers). This study aims to develop a technology for using ameliorant to improve the chemical properties of peat soil. Specifically, through this study, the dosage combination of vulcan tuff ash and dolomite can be identified. which can substitute the use of artificial fertilizers (inorganic) so that it can increase the growth and production of immature liberica coffee plants on peatlands. especially the coffee plantation of farmers in the village of mekar jaya, betara district, tanjung jabung west district. From the results of this study it can be concluded that the treatment of volcanic ash and dolomite did not show significant differences in plant height parameters and, stem diameter. but it gives a real difference to the growth of live area, the number of flowers per bunch and the number of flowers in each bunch. treatment of volcanic ash 500 / gr / tree and dolomite 500 / gr / tree and a combination of volcanic ash 250 / gr / tree + dolomite 250 / gr / tree after 7 weeks of application can significantly spur on the initiation of flowering an average of 7 bunches of branch flowers if compare with control (no treatment). Likewise, observations 8 weeks after application showed the same thing, there was an increase in the number of flowers formed an average of 11 flower clumps branching. From the results of this study, it can be concluded that the provision of ameliorant from vulcan tuff ash and dolomite can improve the chemical properties of peat soil so as to increase nutrient availability for growth and production of the Liberika coffee plant. From the results of this study, it can also be suggested that the use of volcanic ash and dolomite at a dose of 250-500 gr / tree to accelerate the productive phase of immature liberica coffee plants (young plants) in peatlands.

Gypsum-Cement Composites Based on Volcanic Ash

The studies’ results to determine the gypsum, ash and Portland cement components proportions, which would ensure a decrease in the specific binder consumption, as well as the ash grain composition’s effect on the properties of the gypsum cement pozzolan composite, are presented. It was revealed that the use of volcanic ash together with Portland cement in gypsum concrete composites allows reducing gypsum consumption by up to 50% without a significant decrease in strength characteristics. At the same time, the developed gypsum concrete composites have increased water resistance. The influence of the ash particle size distribution on the strength properties of the composite is ambiguous; in the compositions with a high ash content it is advisable to use larger fractions, and with a content of less than 50% ash in the composite, - the small fractions. To study the parameters’ effect of the dispersed reinforcement with basalt fibers on the properties of a gypsum-cement composite, an experiment with such a second-order composite rotatable plan as regular hexagon was conducted. It was found that the maximum values ​​of optimization parameters are observed in the central area of ​​the plan with and . The compressive strength of a fiber gypsum cement pozzolan composite increases by 1.15-1.18 times, when bending, by 1.56-1.72 times with respect to the strength of the initial matrix.

Use of silica fume and natural volcanic ash as a replacement to Portland cement: Micro and pore structural investigation using NMR, XRD, FTIR and X-ray microtomography

This work investigates the effectiveness of the use of volcanic ash along with silica fume as a partial replacement for Portland cement. Multiple mix combinations of volcanic ash, silica fume and Portland cement were examined using various pore and microstructure characterization techniques. Hardened cement pastes were cured for 28days and their pore and microstructures were examined using X-ray Microtomography, Magic Angle Spinning (MAS) Nuclear magnetic resonance (NMR) for 27Al and 29Si, X-ray Diffraction (XRD) and Fourier transform infra-red spectroscopy (FTIR). Microstructure examination of mixes prepared with volcanic ash, silica fume and Portland cement revealed the co-existance of calcium silicate hydrate (C-S-H) and calcium–alumino-silicate-hydrate (C-A-S-H) gels, along with other hydration products that led to a reduction in porosity and densification of the cement matrix. These findings indicate that volcanic ash along with silica fume is a viable substitute for Portland cement up to 40% and provides a sustainable, cost effective and environmentally friendly solution to volcanic ash disposal.

Volcanic ash-based geopolymer cements/concretes: the current state of the art and perspectives.

The progress achieved with the use of volcanic ash for geopolymer synthesis has been critically reviewed in this paper. This consists of an overview of mineralogy and chemistry of volcanic ash. The role of chemical composition and mineral contents of volcanic ash on their reactivity during geopolymerization reaction and, consequently, mechanical properties have been accessed. An attempt has been made to establish a relationship between synthesis factors and final properties. A critical assessment of some synthesis conditions has been addressed and some practical recommendations given along with suggestions of future works that have to be done. All this has shown that there are still many works such as durability tests (carbonation, freeze-thaw, resistance, etc.), life cycle analysis, etc. that need to be done in order to satisfy both suitability and sustainability criteria for a large-scale or industrial application.

Microstructure of cement paste with natural pozzolanic volcanic ash and Portland cement at different stages of curing

The use of volcanic ash as a partial substitute to Portland cement can be a viable alternative for producing sustainable and durable cementitious materials. This study investigates the effect of early and late age curing of hardened cement pastes made with volcanic ash and Ordinary Portland Cement (OPC). Pore and microstructure studies were performed on hardened cement pastes prepared with 10% incremental substitution of volcanic ash up to 50% substitution of OPC. Densification in hardened cement pastes was attributed to formation of Calcium Silicate Hydrate (C-S-H) and Calcium-Alumino-Silicate-Hydrate (C-A-S-H) gels, while the development of Magnesium-Silicate-Hydrates (M-S-H) led to decalcification of C-S-H and C-A-S-H gels which resulted in an increase in porosity of the cementitious matrix. A combination of bulk and surface characterization techniques was used to facilitate effective usage of volcanic ash as a potential substitute for Portland cement that provides a sustainable construction material, and environmentally friendly solution to volcanic ash disposal.

Lightweight SCC with volcanic and other natural materials

This paper presents the fresh, mechanical and durability properties of lightweight self-consolidating concrete (LWSCC) mixtures produced from pumice aggregates and supplementary cementing materials derived from various combinations of volcanic ash, pumice powder and metakaolin. The fresh state properties were determined from slump flow, V-funnel flow time, bleeding, air content, setting time and segregation tests. The mechanical properties and durability characteristics such as compressive strength, rapid chloride permeability, ultrasonic pulse velocity, freeze–thaw/frost resistance, resistance to salt scaling and drying shrinkage were evaluated. The use of volcanic ash, pumice and metakaolin as supplementary cementing materials improved resistance to chloride penetration, freeze–thaw and salt scaling. The developed LWSCC mixtures exhibited satisfactory durability and also satisfied the criteria for structural concrete. The application of developed LWSCCs can lead to low-cost sustainable construction in volcanic areas around the world.

Optimization of the Use of Volcanic Ash of Mount Sinabung Eruption as the Substitution for Fine Aggregate

Mount Sinabung is one of the volcanoes which are categorized as an active volcano in the world. Recently, volcanic activities of some volcanoes in Indonesia are increasing causing the increase in natural materials to be spouted from the volcanoes that can be used as construction materials such as sand, rocks and ash. Chemical substances contained in volcanic ash of Mount Sinabung is more dominated by SiO2 (74.3%), AL2O3 (3.3%), and CaO (1.79) which has been studied in the Research and Industrial Standardization Center, Medan. The content of SiO2 in the volcanic ash was the basis for this research. The objective of this work is to find out the influence of the volcanic ash as the substitution of fine aggregate.The variation of volcanic ash used in the research was 5%, 10%, 15%, 20%, 25%, and 100% with two variations treatment process, by curing the hydrocooling and keeping the room temperature within 28 days. The analysis and the method of the research were referred to SNI 03-0347-1989. Based an experimental results the ideal percentage of variation which had met SNI 03-0347-1989 was identified, that is 10%.Optimum average compressive strength and tensile strength were obtained, 17.19MPa and 2.67MPa respectively. Optimum absorbtion were also studied, 4.142%.

Possible use of volcanic ash as a filler in polyphenylene sulfide composites: Thermal, mechanical, and erosive wear properties

It is a common practice to use particle materials as fillers to improve engineering properties of polymer composites and to lower the cost of final products. There is an obvious cost advantage of compounding volcanic ash (VA) in polymers, either to replace traditional fillers. This study is concerned with thermal, mechanical, and erosive properties of VA‐filled polyphenylene sulfide (PPS) composites. Composite samples containing VA particles at various concentrations (0, 2.5, 5, 10, 15, and 20 wt%) were manufactured by twin screw extruder and injection molding machine. Thermal properties were investigated by thermogravimetric and dynamic mechanical analysis methods. Erosive wear properties were investigated by performing solid particle erosion tests at 30º and 90º impingement angles. The mechanical properties such as flexural strength and modulus of uneroded samples and residual flexural strength and modulus of eroded composite samples were determined by three‐point bending tests. Results show that thermal, mechanical, and residual mechanical properties of the PPS composite were significantly improved by adding VA, although erosion resistance was decreased markedly. It was concluded that VA can be used as a reinforcement in PPS composites to improve thermal and mechanical properties and to reduce the cost of the PPS composites. POLYM. COMPOS., 35:1826–1833, 2014. © 2014 Society of Plastics Engineers

Use of volcanic ash and its impact on algae proliferation in drinking water filtration

With increasing pollution of the available water resources, development of safe drinking water supplies is increasingly becoming a challenge, both for developing and developed countries. To alleviate the prevailing difficulties, approaches should focus on sustainable water supply and treatment systems that require minimal maintenance and operator skills. In this study, a pre-treatment of water containing algae using a combination of volcanic ash (VA) and sand in a filtration system was assessed. The results indicated that a combination of VA and sand performed better in the removal of algae than sand alone. However, it was noted that different algae genera were removed at different rates within the two types of media arrangement. In addition, there was an increase in the filtration run length of the ash-sand columns with VA on top of sand of about two and half times compared with the sand columns. It is therefore anticipated that pre-treatment of raw water laden with algae using ash-sand would probably improve on the performance of the subsequent conventional processes in removing intact cells of algae and thus reduce the threat of releasing toxins into the water that may not be removed by the subsequent conventional treatment processes.

THE YABNAL-MOTUL CERAMIC COMPLEX OF THE LATE CLASSIC PERIOD AT CHICHEN ITZA

AbstractOur understanding of the history of ancient Chichen Itza has been advanced significantly in recent years by the Instituto Nacional de Antropología e Historia's Chichen Itza Archaeological Project. One important advance has been the definition of a new ceramic complex for the site of Yabnal, which dates to the Late Classic period, and corresponds to the Motul ceramic complex of Mayapan. The majority of materials used to define the Yabnal complex come from recent excavation of terraces and platforms distributed throughout the entire area occupied by Chichen Itza in its heyday, but also includes finds in association with the construction and use of buildings with rooms such as the substructure of the Temple of the Initial Series. The most important ceramic materials include complete and restorable vessels obtained from sealed contexts. The Yabnal ceramic complex displays a variety of local and imported wares, similar to those found elsewhere in the northern plains, with the Slate Ware group proving possibly the most important. Ceramic Slate Ware is a high-quality ceramic characterized by the frequent use of volcanic ash as temper, and demonstrates a deeply rooted tradition in northern Yucatan, spanning roughly 600 years. Although most recent discussion of ceramics at Chichen Itza has focused on the Terminal Classic and Postclassic periods, this study examines the early Yabnal ceramic complex of the Late Classic period with a focus on the site, its chronology, and the important implications this ceramic complex has for the general history of the northern plains.

Fresh, Mechanical, and Durability Characteristics of Self-Consolidating Concrete Incorporating Volcanic Ash

Self-consolidating concrete (SCC) is known for its excellent deformability, high resistance to segregation, and use in congested reinforced concrete structures characterized by difficult casting conditions without applying vibration. The use of known mineral admixtures such as fly ash and slag cement has proved very effective in the production of nonexpensive SCC with satisfactory fresh and hardened properties. However, the use of volcanic ash (VA) in SCC is new and can provide low cost SCC. This paper presents fresh, mechanical, and durability characteristics of VA based SCC mixtures (VA-SCCs). VA-SCCs are developed by varying water-to-binder ratio, percentages of VA as cement replacement, and dosages of superplasticizer (SP). Mix design parameters are optimized to achieve minimum use of SP and optimum use of VA. The fresh concrete properties are determined from slump flow, V-funnel flow time, bleeding, air content, and segregation tests. The mechanical properties and durability characteristics such as compressive strength, freezing-thawing resistance, rapid chloride permeability, surface scaling resistance, and drying shrinkage are determined to evaluate the performance of VA-SCCs. The study produces encouraging results and confirms the production of satisfactory VA based SCC mixtures with acceptable properties. VA-SCCs having a minimum strength of 15 MPa (requirement for some structural concrete applications) can be obtained by replacing up to 50% (by mass) of cement by VA. Development of nonexpensive and environmental friendly VA-SCC with acceptable strength and durability characteristics (as illustrated in this study) is extremely helpful for the sustainable development and rehabilitation of volcanic disaster areas around the world.

Volcanic ash as alternative raw materials for traditional vitrified ceramic products

Investigation on the use of volcanic ash as 100% raw materials for traditional vitrified ceramic products is reported. X-ray diffraction (XRD), thermogravimetric–thermal differential analyses (DTA–TGA) and chemical analysis were used to characterise raw samples. Fired specimens were used to evaluate their ceramic properties. Volcanic ash contains essentially classical traditional ceramic oxides, plagioclase, pyroxene and olivine as principal minerals. In the temperature range 1100–1150°C, they present dense structure, low open porosity, without isolated quartz grains. The fired materials properties were found to be in agreement with those of stoneware class BI referring to standard ISO 13006 (i.e.the water absorption values were <1·5%). The presence of a sufficiently extended glassy phase capable of embedding crystalline phases developed during sintering allows comparison of the microstructure of fired volcanic ash with that of traditional porcelain or stoneware.

Volcanic history of El Chichón Volcano (Chiapas, Mexico) during the Holocene, and its impact on human activity

Before its devastating eruption in 1982, El Chichon Volcano was little known and did not appear on any listings of hazardous volcanoes. Subsequent geologic studies, based on stratigraphic and radiocarbon investigations, showed that at least three explosive eruptions had occurred previously at this volcano. In this paper, we present the result of recent studies on the stratigraphy of the volcano and new radiocarbon ages which show that at least 11 eruptions have taken place at El Chichon in the past 8000 years. Explosive events, most of them producing block-andash flow and surge deposits, occurred around 550, 900, 1250, 1500, 1600, 1900, 2000, 2500, 3100, 3700 and 7700 years BP. The juvenile products of these eruptions have a trachyandesitic composition with similar degree of evolution, as evidenced from their SiO2 abundance and depletion in MgO, CaO, TiO2, as well as trace and rare earth elements. This suggests segregation of olivine and orthopyroxene from the melt. Since human settlements in southeast Mexico and Central America can be traced as far back as approximately 2500 years BP, most of these events probably affected human activity. In fact, there are reports of pottery shards and other artifacts in deposits from the eruption of 1250 BP. Pottery fragments in deposits of an eruption that took place 2500 BP are also reported in this paper. Thus, the impact of the volcano on human activities has been frequent, with most of the repose intervals lasting between 100 to 600 years. The impact of the eruptions was probably of greater than local extent, because airfall tephra could reach distant sites and possibly even affect weather. The eruptive history of El Chichon also offers clues in the investigation of the Maya civilization. Several researchers have considered the volcano as an important factor in the answer to some intriguing questions such as the extensive use of volcanic ash in Late Classic Maya ceramics or, of greater importance, the causes of the collapse of the Classic Maya civilization.