Damiano Sarocchi | Universidad Autónoma de San Luis Potosí (original) (raw)

Papers by Damiano Sarocchi

International Journal of Multiphase Flow, Dec 1, 2022

International Journal of Multiphase Flow, Nov 1, 2023

Computers & Geosciences, May 1, 2020

Abstract In this paper, an algorithm for clast roundness classification based on the Radon transf... more Abstract In this paper, an algorithm for clast roundness classification based on the Radon transform is presented. The degree of roundness is determined by processing the sinogram of the clast image. The algorithm consists in applying two low-pass filters to the sinogram, obtaining the inverse Radon transform and comparing the filtered images with the original image. For rounded particles, the difference between the original image and either of the filtered images will be small. For angular clasts, the difference will be greater than for rounded clasts, due to the presence of high-frequency components. In the comparison process, each of the two filtered images are subtracted from the original image to yield two difference images. Since the data are binary, these two images present topologically unconnected regions that correspond to the particle's edges. The percentage of non-overlapping area between the original and the difference images, and the number of regions are used to classify the morphology of the clast. The results have been validated using a comparison chart designed for visual roundness estimation. The comparison chart, consisting of five roundness classes, was proposed by Russell, Taylor and, Pettijohn (Muller, 1967). Two cutoff frequencies, one to classify well-rounded, rounded and sub-rounded clasts and another for angular and sub-angular classes, were used. The proposed algorithm correctly classifies the roundness classes of the visual graph. The results provided by the algorithm were compared with the classification performed by a group of experts. The algorithm assigned 92% of the clasts to the same classes as the human experts. We also propose Gaussian models, which are useful to classify the particles into the five classes. We have developed a user-friendly software to carry out the roundness classification algorithm. This software was developed on the MATLAB platform and can be freely downloaded from the public repository.

Revista Mexicana De Ciencias Geologicas, 2008

The 13 ka dome destruction is the youngest event of this type, and originated a 0.11 km 3 block-a... more The 13 ka dome destruction is the youngest event of this type, and originated a 0.11 km 3 block-andash fl ow deposit on the northeastern sector of the volcano, here named El Refugio fl ow. The deposit consists of two facies: channel-like, up to 10 m thick, monolithologic, that is composed of up to fi ve units, with decimetric dacitic clasts set in a sandy matrix; and a lateral facies that consists of a gray, sandy horizon, up to 4 m thick. A 30 cm-thick surge layer lies down at the base of the sequence. The main component is a dacitic lava, with variable degree of vesciculation, with mineral association of Pl-Hbl-Opx. Stratigraphic and petrographic features indicate that the dome was quickly extruded on the summit of the volcano, and its collapse was accompanied by an explosive component. The magmatic process that probably triggered the eruption was an overheating of the magma chamber that induced a self-mixing mechanism yielding to an overpressurization of the system. Finally, the identifi cation of an explosive component associated with dome destruction events at Nevado de Toluca volcano clearly indicate the high risk that a future event with such characteristics can represent for populated areas around the volcano.

Abstracts with programs, 2016

, for their help during the field work at Mt. St. Helens. We are also grateful to Jason Watt and ... more , for their help during the field work at Mt. St. Helens. We are also grateful to Jason Watt and the Department of Geosciences of the Boise State University for the technical support. This work was partially supported by Ciencias Básica CONACyT projects (SEP-83301) and CONACYT-Ciencia Básica-2012-01-184060, PROMEP UASLP-PTC-41, Instituto Panamericano de Geografía e Historia.

AGU Fall Meeting Abstracts, Dec 1, 2018

Bulletin of Volcanology, Oct 6, 2016

Laboratory experiments on granular flows using natural material were carried out in order to inve... more Laboratory experiments on granular flows using natural material were carried out in order to investigate the behaviour of granular flows passing over a break in slope. Sensors in the depositional area recorded the flow kinematics, while video footage permitted reconstruction of the deposit formation, which allowed investigation of the deposit shape as a function of the change in slope. We defined the slope-angle ratio as the proportion between slope angle in the depositional area and that of the channel. When the granular flow encounters the break in slope part of the flow front forms a bouncing clast zone due to elastic impact with the expansion box floor. During this process, part of the kinetic energy of the dense granular flow is transferred to elutriating fine ash, which subsequently forms turbulent ash cloud accompanying the granular flow until it comes to rest. Morphometric analysis of the deposits shows that they are all elliptical, with an almost constant minor axis and a variable major axis. The almost constant value of the minor axis relates to the spreading angle of flow at the end of the channel, which resembles the basal friction angle of the material. The variation of the major axis is interpreted to relate to the effect of competing inertial and frictional forces. This effect also reflects the partitioning of centripetal and tangential velocities, which changes as the flow passes over the break in slope. After normalization, morphometric data provided empirical relationships that highlight the dependence of runout from the product of slope-angle ratio and the difference in height between granular material release and deposit. The empirical relationships were tested against the runouts of hot avalanches formed during the 1944 ad eruption at Vesuvius, with differences among actual and calculated values are between 1.7 and 15 %. Velocity measurements of laboratory granular flows record deceleration paths at different breaks in slope. When normalized, the velocity data show third-order polynomial fit, highlighting a complex behaviour involving interplay between inertial and frictional forces. The theoretical velocity decays were tested against the data published for volcaniclastic debris flows of the 5–6 May 1998 event in the Sarno area. The comparison is very good for non-channelized debris flows, with significant differences between actual and calculated velocities for the channelized debris flows.

AGUSM, May 1, 2007

The Nevado de Toluca is an active volcano located in the central sector of the Trans-Mexican Volc... more The Nevado de Toluca is an active volcano located in the central sector of the Trans-Mexican Volcanic Belt, 80 km southwest of Mexico City. Activity at this andesitic to dacitic stratovolcano began ca. 2.6 Ma ago. During the last 42 ka, the volcano has been characterized by different eruptive styles, including five dome collapses dated at 37, 32, 28, 26,

Journal of South American Earth Sciences, Aug 1, 2021

Abstract The distribution and characteristics of volcaniclastic deposits are the result of the in... more Abstract The distribution and characteristics of volcaniclastic deposits are the result of the interplay among numerous factors acting at different and multileveled scales of space and time. Such complexity requires multiple techniques for the study of volcanic regions. This approach provides a strong basis for understanding volcanic processes and their relationship with the resulting landforms or deposits and for reconstructing dynamic properties of flows. The aim of this paper is thus to understand the interplay between the geomorphologic environment and the origin and transport of large-magnitude debris flows. For this reason, we selected the eastern sector of the Citlaltepetl volcano and the Teteltzingo lahar event (Veracruz, Mexico). Information from geomorphological and morphometric analysis (including the linear features) was linked with field and shape-fabric data on selected outcrops. The study area was divided into three morphometric zones based on their elevation, slope, drainage network, and the trend in linear features. These zones are volcanic mountain zone, minor folded ranges and cumulative volcaniclastic plain. The geomorphological map enabled us to understand the origin of the landforms observed in each of the three morphometric zones. The characteristics of the Teteltzingo lahar deposit (i.e., geographic distribution, thickness and components) are associated with the morphologic and morphometric characteristics of the landscape. The particle shape-fabric analysis gave evidence that particle iso-orientation is consistent with the flow direction and orientation of some regional linear features, especially in the medial and distal zones. Moreover, the degree of iso-orientation was shown to be dependent on travel distance and particle diameter. The highest degree of iso-orientation was found in the coarse particles (gravel grain-size) throughout the entire deposit, being more developed in the distal zone. The evidence presented here suggests an interplay between geomorphological–structural controls and their spatial variability with the distribution of large-magnitude lahars. This highlights the importance of a multi-scale vision of mass movement phenomena that show how morphological and sedimentological characteristics are linked and could affect the generation and dynamics of future flows.

Journal of Volcanology and Geothermal Research, Feb 1, 2021

The behaviour of dry and wet volcanic granular flows is one of the main research topics in presen... more The behaviour of dry and wet volcanic granular flows is one of the main research topics in present day geophysics and volcanology. It involves various disciplines (e.g. sedimentology, geophysics, fluid dynamics) and investigation techniques (e.g. field studies, laboratory experiments, computational fluid dynamics). The vast interest is justified by the complex nature of these flows and their very dangerous nature that threaten millions of people around the world. In the last decade, computational fluid dynamics has become one of the main instruments used to reproduce past events of volcanic granular flows or to predict their behavior and potential hazard. In this study, we tested two of the most used codes for simulating volcanic granular flows, TITAN2D and FLO2D, against well studied natural cases (the 1998 wet granular flows in the Sarno area and the 2005 block and ash flows at Colima volcano) and large-scale experiments on granular flows. Comparison between simulated parameters and real ones were carried out in order to evaluate strengths and weaknesses of the two numerical codes. TITAN2D results showed how the basal friction angle is fundamental to control numerical simulations and its dependence on the topographic complexities and slope-angle ratio. Simulation of large scale experiments offered a good relationship between slope angle ratio at break in slope and basal friction angle, which is useful for application to small drainage basins with not complex channel morphology. FLO2D suffers the lack of rheometric parameters α and β for volcaniclastic material, but is less sensitive of DEM resolution with respect to TITAN2D.

Journal of Volcanology and Geothermal Research, 1996

Computer-assisted Image Analysis can be succesfully used to derive quantitative information about... more Computer-assisted Image Analysis can be succesfully used to derive quantitative information about grain-size distribution, particle shape and fabric on both consolidated and unconsolidated solid aggregates. We have developed a new analytical method that provides a series of quantitative textural parameters from whatever particulate deposits by combining commercial image acquisition system with devoted C-software. After exhaustive tests of the method, we applied it to a widespread Quaternary ignimbrite formation in central Italy (the Orvieto-Bagnoregio formation). The results suggest some new aspects of emplacement mechanisms of ignimbrites: (I) elongated particles shows variable degrees of flow-related preferred orientation both on horizontal and vertical planes; (2) vertical variations of flow-related preferred particle orientations follow a "zig-zag" pattern that we interpret to result from deposition by progressive aggradation during the passage of a particulate flow. The filling up of paleovalleys by means of progressive aggradation proceeds flank to flank due to alternating flow directions, induced by the already deposited material; (3) the occurrence of vertically spaced peaks on the strength of clast orientation suggests the existence of discrete depositional units deposited by aggradation from an unsteady but persisting flow. Strong fabrics are inferred to result from the high amount of shear stress imparted to particles at the depositional boundary layer, which at the same time can be responsible for the development of the basal inversely graded layer. Image analysis can also provide useful indications of paleoflow directions, paleotopographic details and ignimbrite source areas.

Proceedings of SPIE, Aug 15, 2011

ABSTRACT For several decades geologists, have faced several difficulties to characterize properti... more ABSTRACT For several decades geologists, have faced several difficulties to characterize properties of sedimentary particles. These particles usually have a wide range of sizes and shapes. For size measurements, there are several instruments, based on different principles. However, the use of these instruments is not very widespread; moreover, each one can allows the measurement of a small fraction of the whole granulometric distribution, because particle size covers several order of magnitude. Several authors have demonstrated the feasibility to perform these tests by means of digital image processing. In this paper we propose an optical method and equipment in order to obtain particle size in a range from 30 microns to 50 mm, morphological data and density. A fluid is used as vehicle for particle transportation and it allows the dispersion of the particles uniformly trough the sample, helping the segmentation process, done subsequently, by means of a digital image algorithm. The proposed scheme uses a background illumination for accurate measurement of particle size due to the complexity of its component phases. Using the proposed digital image processing algorithm, up to 41 different measurements can be done on each particle (spanning from geometrical up to morphological data using the Fourier method). It also uses a tracking algorithm that gives the particle speed to determine their density according to the Stokes law. Experiments have demonstrated both accuracy and repeatability of this method compared with other methods of measurement.

Journal of Volcanology and Geothermal Research, 2022

Journal of Volcanology and Geothermal Research, Dec 1, 2016

Influence of particle density on flow behavior and deposit architecture of concentrated pyroclast... more Influence of particle density on flow behavior and deposit architecture of concentrated pyroclastic density currents over a break in slope: Insights from laboratory experiments.

Journal of Volcanology and Geothermal Research, Aug 1, 2014

AGU Fall Meeting Abstracts, Dec 1, 2019

AGU Fall Meeting Abstracts, Dec 1, 2018

Pyroclastic density currents (PDCs) are gravity-driven avalanches of gas and solid particles that... more Pyroclastic density currents (PDCs) are gravity-driven avalanches of gas and solid particles that occur during volcanic eruptions. PDCs happen with little warning and travel long distances at high velocities, making them one of the most significant volcanic hazards. Through my research, I investigate the physical processes occurring within PDCs. Unfortunately, the danger and unpredictability of these currents makes studying PDCs in real time difficult. Instead, I integrate observations of PDC deposits with laboratory experiments simulating PDCs under controlled conditions. In combining these approaches, I seek to understand what controls the behavior and hazard potential of these dangerous volcanic phenomena

International Journal of Multiphase Flow, Dec 1, 2022

International Journal of Multiphase Flow, Nov 1, 2023

Computers & Geosciences, May 1, 2020

Abstract In this paper, an algorithm for clast roundness classification based on the Radon transf... more Abstract In this paper, an algorithm for clast roundness classification based on the Radon transform is presented. The degree of roundness is determined by processing the sinogram of the clast image. The algorithm consists in applying two low-pass filters to the sinogram, obtaining the inverse Radon transform and comparing the filtered images with the original image. For rounded particles, the difference between the original image and either of the filtered images will be small. For angular clasts, the difference will be greater than for rounded clasts, due to the presence of high-frequency components. In the comparison process, each of the two filtered images are subtracted from the original image to yield two difference images. Since the data are binary, these two images present topologically unconnected regions that correspond to the particle's edges. The percentage of non-overlapping area between the original and the difference images, and the number of regions are used to classify the morphology of the clast. The results have been validated using a comparison chart designed for visual roundness estimation. The comparison chart, consisting of five roundness classes, was proposed by Russell, Taylor and, Pettijohn (Muller, 1967). Two cutoff frequencies, one to classify well-rounded, rounded and sub-rounded clasts and another for angular and sub-angular classes, were used. The proposed algorithm correctly classifies the roundness classes of the visual graph. The results provided by the algorithm were compared with the classification performed by a group of experts. The algorithm assigned 92% of the clasts to the same classes as the human experts. We also propose Gaussian models, which are useful to classify the particles into the five classes. We have developed a user-friendly software to carry out the roundness classification algorithm. This software was developed on the MATLAB platform and can be freely downloaded from the public repository.

Revista Mexicana De Ciencias Geologicas, 2008

The 13 ka dome destruction is the youngest event of this type, and originated a 0.11 km 3 block-a... more The 13 ka dome destruction is the youngest event of this type, and originated a 0.11 km 3 block-andash fl ow deposit on the northeastern sector of the volcano, here named El Refugio fl ow. The deposit consists of two facies: channel-like, up to 10 m thick, monolithologic, that is composed of up to fi ve units, with decimetric dacitic clasts set in a sandy matrix; and a lateral facies that consists of a gray, sandy horizon, up to 4 m thick. A 30 cm-thick surge layer lies down at the base of the sequence. The main component is a dacitic lava, with variable degree of vesciculation, with mineral association of Pl-Hbl-Opx. Stratigraphic and petrographic features indicate that the dome was quickly extruded on the summit of the volcano, and its collapse was accompanied by an explosive component. The magmatic process that probably triggered the eruption was an overheating of the magma chamber that induced a self-mixing mechanism yielding to an overpressurization of the system. Finally, the identifi cation of an explosive component associated with dome destruction events at Nevado de Toluca volcano clearly indicate the high risk that a future event with such characteristics can represent for populated areas around the volcano.

Abstracts with programs, 2016

, for their help during the field work at Mt. St. Helens. We are also grateful to Jason Watt and ... more , for their help during the field work at Mt. St. Helens. We are also grateful to Jason Watt and the Department of Geosciences of the Boise State University for the technical support. This work was partially supported by Ciencias Básica CONACyT projects (SEP-83301) and CONACYT-Ciencia Básica-2012-01-184060, PROMEP UASLP-PTC-41, Instituto Panamericano de Geografía e Historia.

AGU Fall Meeting Abstracts, Dec 1, 2018

Bulletin of Volcanology, Oct 6, 2016

Laboratory experiments on granular flows using natural material were carried out in order to inve... more Laboratory experiments on granular flows using natural material were carried out in order to investigate the behaviour of granular flows passing over a break in slope. Sensors in the depositional area recorded the flow kinematics, while video footage permitted reconstruction of the deposit formation, which allowed investigation of the deposit shape as a function of the change in slope. We defined the slope-angle ratio as the proportion between slope angle in the depositional area and that of the channel. When the granular flow encounters the break in slope part of the flow front forms a bouncing clast zone due to elastic impact with the expansion box floor. During this process, part of the kinetic energy of the dense granular flow is transferred to elutriating fine ash, which subsequently forms turbulent ash cloud accompanying the granular flow until it comes to rest. Morphometric analysis of the deposits shows that they are all elliptical, with an almost constant minor axis and a variable major axis. The almost constant value of the minor axis relates to the spreading angle of flow at the end of the channel, which resembles the basal friction angle of the material. The variation of the major axis is interpreted to relate to the effect of competing inertial and frictional forces. This effect also reflects the partitioning of centripetal and tangential velocities, which changes as the flow passes over the break in slope. After normalization, morphometric data provided empirical relationships that highlight the dependence of runout from the product of slope-angle ratio and the difference in height between granular material release and deposit. The empirical relationships were tested against the runouts of hot avalanches formed during the 1944 ad eruption at Vesuvius, with differences among actual and calculated values are between 1.7 and 15 %. Velocity measurements of laboratory granular flows record deceleration paths at different breaks in slope. When normalized, the velocity data show third-order polynomial fit, highlighting a complex behaviour involving interplay between inertial and frictional forces. The theoretical velocity decays were tested against the data published for volcaniclastic debris flows of the 5–6 May 1998 event in the Sarno area. The comparison is very good for non-channelized debris flows, with significant differences between actual and calculated velocities for the channelized debris flows.

AGUSM, May 1, 2007

The Nevado de Toluca is an active volcano located in the central sector of the Trans-Mexican Volc... more The Nevado de Toluca is an active volcano located in the central sector of the Trans-Mexican Volcanic Belt, 80 km southwest of Mexico City. Activity at this andesitic to dacitic stratovolcano began ca. 2.6 Ma ago. During the last 42 ka, the volcano has been characterized by different eruptive styles, including five dome collapses dated at 37, 32, 28, 26,

Journal of South American Earth Sciences, Aug 1, 2021

Abstract The distribution and characteristics of volcaniclastic deposits are the result of the in... more Abstract The distribution and characteristics of volcaniclastic deposits are the result of the interplay among numerous factors acting at different and multileveled scales of space and time. Such complexity requires multiple techniques for the study of volcanic regions. This approach provides a strong basis for understanding volcanic processes and their relationship with the resulting landforms or deposits and for reconstructing dynamic properties of flows. The aim of this paper is thus to understand the interplay between the geomorphologic environment and the origin and transport of large-magnitude debris flows. For this reason, we selected the eastern sector of the Citlaltepetl volcano and the Teteltzingo lahar event (Veracruz, Mexico). Information from geomorphological and morphometric analysis (including the linear features) was linked with field and shape-fabric data on selected outcrops. The study area was divided into three morphometric zones based on their elevation, slope, drainage network, and the trend in linear features. These zones are volcanic mountain zone, minor folded ranges and cumulative volcaniclastic plain. The geomorphological map enabled us to understand the origin of the landforms observed in each of the three morphometric zones. The characteristics of the Teteltzingo lahar deposit (i.e., geographic distribution, thickness and components) are associated with the morphologic and morphometric characteristics of the landscape. The particle shape-fabric analysis gave evidence that particle iso-orientation is consistent with the flow direction and orientation of some regional linear features, especially in the medial and distal zones. Moreover, the degree of iso-orientation was shown to be dependent on travel distance and particle diameter. The highest degree of iso-orientation was found in the coarse particles (gravel grain-size) throughout the entire deposit, being more developed in the distal zone. The evidence presented here suggests an interplay between geomorphological–structural controls and their spatial variability with the distribution of large-magnitude lahars. This highlights the importance of a multi-scale vision of mass movement phenomena that show how morphological and sedimentological characteristics are linked and could affect the generation and dynamics of future flows.

Journal of Volcanology and Geothermal Research, Feb 1, 2021

The behaviour of dry and wet volcanic granular flows is one of the main research topics in presen... more The behaviour of dry and wet volcanic granular flows is one of the main research topics in present day geophysics and volcanology. It involves various disciplines (e.g. sedimentology, geophysics, fluid dynamics) and investigation techniques (e.g. field studies, laboratory experiments, computational fluid dynamics). The vast interest is justified by the complex nature of these flows and their very dangerous nature that threaten millions of people around the world. In the last decade, computational fluid dynamics has become one of the main instruments used to reproduce past events of volcanic granular flows or to predict their behavior and potential hazard. In this study, we tested two of the most used codes for simulating volcanic granular flows, TITAN2D and FLO2D, against well studied natural cases (the 1998 wet granular flows in the Sarno area and the 2005 block and ash flows at Colima volcano) and large-scale experiments on granular flows. Comparison between simulated parameters and real ones were carried out in order to evaluate strengths and weaknesses of the two numerical codes. TITAN2D results showed how the basal friction angle is fundamental to control numerical simulations and its dependence on the topographic complexities and slope-angle ratio. Simulation of large scale experiments offered a good relationship between slope angle ratio at break in slope and basal friction angle, which is useful for application to small drainage basins with not complex channel morphology. FLO2D suffers the lack of rheometric parameters α and β for volcaniclastic material, but is less sensitive of DEM resolution with respect to TITAN2D.

Journal of Volcanology and Geothermal Research, 1996

Computer-assisted Image Analysis can be succesfully used to derive quantitative information about... more Computer-assisted Image Analysis can be succesfully used to derive quantitative information about grain-size distribution, particle shape and fabric on both consolidated and unconsolidated solid aggregates. We have developed a new analytical method that provides a series of quantitative textural parameters from whatever particulate deposits by combining commercial image acquisition system with devoted C-software. After exhaustive tests of the method, we applied it to a widespread Quaternary ignimbrite formation in central Italy (the Orvieto-Bagnoregio formation). The results suggest some new aspects of emplacement mechanisms of ignimbrites: (I) elongated particles shows variable degrees of flow-related preferred orientation both on horizontal and vertical planes; (2) vertical variations of flow-related preferred particle orientations follow a "zig-zag" pattern that we interpret to result from deposition by progressive aggradation during the passage of a particulate flow. The filling up of paleovalleys by means of progressive aggradation proceeds flank to flank due to alternating flow directions, induced by the already deposited material; (3) the occurrence of vertically spaced peaks on the strength of clast orientation suggests the existence of discrete depositional units deposited by aggradation from an unsteady but persisting flow. Strong fabrics are inferred to result from the high amount of shear stress imparted to particles at the depositional boundary layer, which at the same time can be responsible for the development of the basal inversely graded layer. Image analysis can also provide useful indications of paleoflow directions, paleotopographic details and ignimbrite source areas.

Proceedings of SPIE, Aug 15, 2011

ABSTRACT For several decades geologists, have faced several difficulties to characterize properti... more ABSTRACT For several decades geologists, have faced several difficulties to characterize properties of sedimentary particles. These particles usually have a wide range of sizes and shapes. For size measurements, there are several instruments, based on different principles. However, the use of these instruments is not very widespread; moreover, each one can allows the measurement of a small fraction of the whole granulometric distribution, because particle size covers several order of magnitude. Several authors have demonstrated the feasibility to perform these tests by means of digital image processing. In this paper we propose an optical method and equipment in order to obtain particle size in a range from 30 microns to 50 mm, morphological data and density. A fluid is used as vehicle for particle transportation and it allows the dispersion of the particles uniformly trough the sample, helping the segmentation process, done subsequently, by means of a digital image algorithm. The proposed scheme uses a background illumination for accurate measurement of particle size due to the complexity of its component phases. Using the proposed digital image processing algorithm, up to 41 different measurements can be done on each particle (spanning from geometrical up to morphological data using the Fourier method). It also uses a tracking algorithm that gives the particle speed to determine their density according to the Stokes law. Experiments have demonstrated both accuracy and repeatability of this method compared with other methods of measurement.

Journal of Volcanology and Geothermal Research, 2022

Journal of Volcanology and Geothermal Research, Dec 1, 2016

Influence of particle density on flow behavior and deposit architecture of concentrated pyroclast... more Influence of particle density on flow behavior and deposit architecture of concentrated pyroclastic density currents over a break in slope: Insights from laboratory experiments.

Journal of Volcanology and Geothermal Research, Aug 1, 2014

AGU Fall Meeting Abstracts, Dec 1, 2019

AGU Fall Meeting Abstracts, Dec 1, 2018

Pyroclastic density currents (PDCs) are gravity-driven avalanches of gas and solid particles that... more Pyroclastic density currents (PDCs) are gravity-driven avalanches of gas and solid particles that occur during volcanic eruptions. PDCs happen with little warning and travel long distances at high velocities, making them one of the most significant volcanic hazards. Through my research, I investigate the physical processes occurring within PDCs. Unfortunately, the danger and unpredictability of these currents makes studying PDCs in real time difficult. Instead, I integrate observations of PDC deposits with laboratory experiments simulating PDCs under controlled conditions. In combining these approaches, I seek to understand what controls the behavior and hazard potential of these dangerous volcanic phenomena