Introduction to Volcanic Seismology

Transcription

1 Introduction to Volcanic Seismology Second edition Vyacheslav M. Zobin Observatorio Vulcanolo'gico, Universidad de Colima, Colima, Col., Mexico ELSEVIER AMSTERDAM BOSTON HEIDELBERG LONDON * NEW YORK OXFORD PARIS * SAN DIEGO SAN FRANCISCO SINGAPORE * SYDNEY TOKYO

2 Preface to the Second Edition Preface to the First Edition xiii xv 1 Introduction Terms and Definitions Volcanic Terms Tectonic Terms Seismological Terms Subject of the Book 6 Acknowledgments 7 2 Seismicity at Volcanoes History of Seismic Monitoring of Volcanic Activity Classification of Volcanic Earthquakes Sequences of Volcanic Earthquakes Sequences of Volcano-Tectonic Earthquakes Sequences of Eruption Earthquakes 27 3 Fundamentals of Volcanic Seismology Magma Flow within the Volcanic Conduit Magma Flow Regimes Modeling of Magma Flow Regimes Experimental Studies of the Volcanic Processes and Their Applications for the Seismic Sources Experimental Grounds of the Brittle Fracturing in the Rocks at High Temperatures and High Pressure Experimental Grounds of the Origin of Seismic Signals During the Magma Ascending Within the Volcanic Conduit General Description of the Source of Seismic Signals at Volcanoes Equivalent Force System Acting in the Earthquake Source Green's Functions Single Force Seismic Moment Tensor Waveform Inversion 43 4 Origin of Volcano-Tectonic Earthquakes Migration of Magma and Its Seismic Potential Volcanism and Tectonics Source Nature of Volcano-Tectonic Earthquakes 59

3 4.3.1 Waveform and Spectra Tensor Representation of the Source of Volcano-Tectonic Earthquake Models of Volcano-Tectonic Earthquake Sequences 63 5 Volcano-Tectonic Earthquakes at Basaltic Volcanoes: Case Studies Volcano-Tectonic Earthquakes Associated with Shield Volcanoes Kilauea Volcano, Hawaii Volcano-Tectonic Earthquakes Associated with Stratovolcanoes Mount Etna, Sicily r Oshima Volcano, Izu Islands Klyuchevskoy Volcano, Kamchatka Volcano-Tectonic Earthquakes Associated with Fissure Eruptions New Tolbachik Volcanoes, Kamchatka The Ethiopia Rifting Episode Volcano-Tectonic Earthquakes Associated with Caldera Collapse Fernandina Volcano, Galapagos Islands Volcano-Tectonic Earthquakes Associated with Submarine Eruptions Teishi Knoll Volcano, Izu Islands Miyakejima Volcano, Izu Islands 94 6 Volcano-Tectonic Earthquakes at Andesitic Volcanoes: Case Studies Volcano-Tectonic Earthquakes Associated with Volcanic "Directed Blasts" Bezymianny Volcano, Kamchatka Sheveluch Volcano, Kamchatka Volcano-Tectonic Earthquakes Associated with Phreatic and Phreato-Magmatic Explosions El Chichon Volcano, Mexico Volcan de Colima, Mexico Popocatepetl Volcano, Mexico Soufriere Hills Volcano, Montserrat Volcano-Tectonic Earthquakes Associated with Lava Extrusions Volcan de Colima, Mexico Volcano-Tectonic Earthquakes Associated with Flank Eruptions Sakurajima Volcano, Japan Volcano-Tectonic Earthquakes at Dacitic Volcanoes: Case Studies Volcano-Tectonic Earthquakes Associated with Summit Eruptions Mount St. Helens, Cascades Usu Volcano, Hokkaido Unzen Volcano, Kyushu 129

4 vii Pinatubo Volcano, Luzon Volcano-Tectonic Earthquakes Associated with Flank Eruptions Usu Volcano, Hokkaido General Properties of Volcano-Tectonic Earthquake Swarms Properties of Volcano-Tectonic Earthquake Swarms Inferred from the Data of Chapters Temporal Variations Spatial Distributions Posteruption Seismic Activity Duration of Seismic Swarms Prior to Eruption Position of a Volcanic Event According to the Stage of Volcano-Tectonic Earthquake Swarm Additional Data About Volcano-Tectonic Earthquake Swarm Properties Size of Volcano-Tectonic Earthquake Swarm Area Earthquake Swarm Duration Magnitude Frequency Relations of Events in Volcano-Tectonic Earthquake Swarms Some Regularities in the Volcano-Tectonic Earthquake Swarms Proclaiming Reawakening of Andesitic and Dacitic Volcanoes Relationship Between the Duration of Stage 1 and the VEI of Forthcoming Explosion Relationship Between the Duration of Stage 2 and Postexplosion Dome Building The Conceptual Model of Reawakening Process Source Properties of Volcano-Tectonic Earthquakes Focal Mechanisms of Volcano-Tectonic Earthquakes: Double-Couple and Non-Double-Couple Models Double-Couple Model Non-Double-Couple Model Source Spectral Characteristics of Volcano-Tectonic Earthquakes Spectra of Total Records of Volcano-Tectonic Earthquakes Spectral Source Characteristics of Volcano-Tectonic Earthquakes Temporal Variations of the Source Spectral Characteristics and Focal Mechanisms of Volcano-Tectonic Earthquakes in the Course of Volcanic Activity Corner Frequencies Variations Stress-Drop Variations Stress Field Rotations Seismo-Tectonic Deformations in the Volcanic Region 182

5 10 Significant Volcano-Tectonic Earthquakes and Their Role in Volcanic Processes Selection of Significant Volcano-Tectonic Earthquakes that Occurred in the Twentieth Century Focal Rupturing of Significant Volcano-Tectonic Earthquakes and Its Role in Volcanic Processes Rupturing of the Magnitude Mw 5.2 Earthquake Preceding the 1989 Teishi Knoll Submarine Eruption Rupturing of the Magnitude Mw 7.1 Earthquake Preceding the 1996 Akademia Nauk Volcano Subaqual Eruption Rupturing of the Magnitude Mw 5.6 Earthquake Preceding the 1996 Grimsv0tn Volcano Subglacial Eruption The Magnitude 7 Volcano-Tectonic Earthquakes in Volcanic Processes Event No. 2, Katmai, Alaska Event No. 3, Sakurajima, Japan Seismic Hazard of Significant Volcano-Tectonic Earthquakes Maximum Magnitude M max Attenuation of Earthquake Intensity with Distance for Volcanic Earthquakes Recurrence Time Estimation of the Seismic Hazard of Volcanic Activity of Volcan de Colima, Mexico Origin of Eruption Earthquakes Volcanic Processes Generating Seismic Signals of Eruption Earthquakes Processes Within the Volcanic Conduit Volcanic Flows Source Mechanisms of Eruption Earthquakes A Force System Equivalent to a Volcanic Eruption Seismic Moment Tensors of Some Non-Double-Couple Sources of Eruption Earthquakes Models of the Eruption Earthquake Sources Models Based on the Vibration of Magma-Filled Structures Models Based on Degassing Process of Magma Modeling of Seismic Signals Generated by Pyroclastic Flows and Rockfalls Volcanic Tremor 12.1 Seismograms and Spectra 12.2 Location of Volcanic Tremor

6 Oshima Volcano, Izu Islands Etna Volcano, Sicily Volcanic Tremors in Eruptive Process Etna Volcano, Sicily Pavlof Volcano, Alaska Kilauea Volcano, Hawaii Klyuchevskoy Volcano, Kamchatka Relationship Between the Intensity of Volcanic Tremor and Volcanic Events Special Cases of Volcanic Tremors Isolated Tremors Banded Tremor Long-Period Tremor Deep Tremor Seismic Signals Associated with Pyroclastic Flows, Rockfalls, and Lahars Occurrence of Pyroclastic Flows, Rockfalls, and Lahars During Volcanic Eruptions Seismic Signals Associated with Pyroclastic Flows and Rockfalls: Waveforms and Spectra Seismic Signals of Pyroclastic Flows Produced by the Partial Collapse of Lava Dome Seismic Signals of Pyroclastic Flows Produced by the Collapse of Eruption Column Seismic Signals of Pyroclastic Flows Produced by the Explosive Destruction of Growing Lava Dome Seismic Signals Produced by Rockfall' Spectral Characteristics Occurrences of Earthquakes Associated with Pyroclastic Flows and Rockfalls Relationship Between the Pyroclastic Flow and Rockfall Earthquakes and Seismo-Volcanic Activity During Lava Emission Quantification of Pyroclastic Flow and Rockfall Earthquakes Quantification of Pyroclastic Flow and Rockfall Earthquakes Occurring Due to Partial Collapse of the Lava Dome and Recorded by Short-Period Instruments at Volcan de Colima, Mexico Relationship Between the Magnitude of Pyroclastic Flow and Rockfall Earthquakes and the Volume of Pyroclastic Flows Relationship Between the Amplitude of Long-Period Records of Pyroclastic Flow and Rockfall Earthquakes and the Volume of Pyroclastic Flows 281

7 13.6 Location Pyroclastic Flows Using the Amplitude Signals of Earthquakes Seismic Signals Associated with Lahars: Waveforms and Spectra Seismic Signals as a Source of Information About the Lahar Structure Seismic Tracking of Lahars Comparison of the Seismic Characteristics of Pyroclastic Flows and Lahars Seismic Signals Associated with Volcanic Explosions Waveforms and Spectra Strombolian Explosions Vulcanian Explosions Phreato-Magmatic Explosions Nature of the Seismic Signals of Explosive Earthquakes Comparison of the Contemporary Video and Seismic Records During an Explosion Type of Waves Composing the Seismic Signal of an Explosion Sources of Explosion Earthquakes and Their Quantification Multiple Source of Explosions Two-Stage Model of Explosive Process Relationship Between the Seismic Moment of Preliminary LP Phase and the Energy of Explosions for Sakurajima Volcano Volcanic Explosive Process as a Source of Hybrid Earthquakes Location of Explosion Earthquakes Location of the Initial Sub-Events from Waveform Inversion Explosion Sequences Explosion Earthquakes in Eruptive Process Long-Period and Very Long-Period Seismic Signals at Volcanoes Waveforms and Spectra Long-Period Seismic Signals Very Long-Period Seismic Signals Occurrences of LP and VLP Events Nature of LP and VLP Seismic Signals Geometry of the Sources of LP and VLP Seismic Signals Type of Fluid Within the Fluid-Filled Cracks Crack Model Complex Frequencies of the LP Seismic Signal for Different Fluids 341

8 xi Identification of the Type of Fluid from LP Seismic Signals Location of the Sources of LP and VLP Events Conceptual Models of the Relationship Between the Sources of the LP and VLP Seismic Signals and Their Role in Eruptive Process Swarms of Microearthquakes Associated with Effusive and Explosive Activity at Volcanoes Waveforms and Spectra Structure of Microearthquake Swarms Microearthquake Swarms in Eruption Process Kizimen volcano, Kamchatka Stromboli volcano, Aeolean Islands Mount St. Helens, Cascades Ubinas volcano, Peru Volcan de Colima, Mexico Nature of Microearthquakes Similarity Between the Microearthquake Waveforms and the Seismic Signals Well-Associated with the Volcanic Events Quantification of Microearthquakes Nature of Microearthquakes Resolved from Waveform Inversion Acoustic Waves Generated by Volcanic Eruptions Infrasonic Acoustic Waves from Small Volcanic Explosions (VEI 1 and 2) Waveforms and Spectra Families of Infrasonic Signals Source Location of the Infrasonic Events Relationship Between the Amplitudes of the Seismic and Infrasonic Signals Long-Period Acoustic and Acoustic-Gravity Waves from Large Volcanic Explosions (VEI 4 6) Near-Field Waveforms of the Long-Period Acoustic Waves Far-Field Registrations of the Long-Period Acoustic Waves Acoustic Waves Produced by the Lava Dome Collapse and the Propagation of Pyroclastic Flow and Rockfalls Dome Collapse Pyroclastic Flow Propagation Large Rockfall Propagation 398

9 17.4 Acoustic Waves Produced During Volcanic Microearthquake Swarms ("Drumbeats") Utility of the Acoustic Signals for Volcano Activity Monitoring Estimation of the Energy of Eruptive Events Reconstruction of the Process of Dome Collapses and Pyroclastic Flow Movement Monitoring of Phreatic and Strombolian Explosions Seismic Monitoring of Volcanic Activity and Forecasting of Volcanic Eruptions Methodology of Seismic Monitoring of Volcanic Activity Seismic Networks Around Volcanoes Initial Processing of Seismic Data Automatic Classification of the Seismic Signals Location of Seismic Events Applications of Volcanic Seismicity to the Forecasting of Volcanic Eruptions and Predicting of Volcanic Hazards Methods Based on the Statistical Variations in the Parameters of Volcano-Tectonic Earthquakes Chronicle of Some Forecasting of Volcanic Eruptions Based on Seismic Monitoring Seismic Activity at Dormant Volcanic Structures: A Problem of Failed Eruption Failed Eruptions: Case Studies Failed Eruptions at Large Calderas Failed Eruptions at Strato-Volcanoes Failed Eruptions in Rift Settings Modeling of Magma Ascent Resisting Experimental Study of the Ascent of a Fixed Magma Volume Arrest of Propagating Dyke Due to Mechanical Barriers and Density Stratification in an Upper Crustal Horizon Monitoring of the Seismic Activity at Dormant Volcanoes Monitoring of Andesitic and Dacitic Dormant Volcanoes Monitoring of Basaltic Dormant Volcanoes 453 References 457