El Hierro Island

Preface
Acknowledgements
Contents
Geodynamics and Volcanology
1 El Hierro Island Volcanological Science: An Overview
	Abstract
	1.1 Introduction
		1.1.1 El Hierro: An Overview of Its Geodynamic Framework
			1.1.1.1 Geodynamic Background
			1.1.1.2 Lithosphere Structure
			1.1.1.3 Conceptual Models for the Canary Islands
		1.1.2 What Was Learned in the Last Decade?
		1.1.3 Concluding Remarks and Future Challenges
	Acknowledgements
	References
2 Past, Present and Future Volcanic Activity on El Hierro
	Abstract
	2.1 Introduction
	2.2 Volcanic Activity and Evolution of the Island
	2.3 The Compositional Signature of the Rocks
	2.4 Volcanic Activity Through Time
	2.5 Eruptive Styles, Volcano Types and Volcanic Deposits
	2.6 Volcano-Structural System
	2.7 Future Potentially Hazardous Volcanic Processes
		2.7.1 Numerical Scenario Simulations of a Likely Future Eruption
	2.8 The 2011–2012 Submarine Eruption
		2.8.1 On the Origin of the Xenopumices
		2.8.2 Lava Balloons Emissions
	2.9 Present and Future Pending Actions on the Island
	References
3 Review of Submarine Eruptions in El Hierro Prior to Tagoro
	Abstract
	3.1 Introduction
	3.2 Geological Setting
	3.3 Methods
	3.4 Submarine Volcanism of the Early Emergence of the Island
		3.4.1 Punta Del Corral
		3.4.2 Hoya Del Verodal
	3.5 Surtseyan Deposits on the Rifts
		3.5.1 Las Bermejas De Tierra
		3.5.2 El Bajón
		3.5.3 Baja De Anacón
		3.5.4 Punta De La Arena Deposits (PAD)
	3.6 Historical Surtseyan and Submarine Volcanism
		3.6.1 June-November 1721 Surtseyan Eruption: A Legend?
		3.6.2 Thirteenth September 1777 Submarine Eruption
		3.6.3 The Seismic Crisis of 27th March–27th June 1793: A Submarine Eruption?
	3.7 Discussion and Conclusions
	Acknowledgements
	References
The 2011–2014 Volcanic Unrest and Submarine Eruption: Geology
4 From Magma Source to Volcanic Sink Under Tagoro Volcano (El Hierro, Canary Islands): Petrologic, Geochemical and Physiographic Evolution of the 2011–2012 Submarine Eruption
	Abstract
	4.1 Introduction
	4.2 Overview of Tagoro and El Hierro’s Geology
	4.3 Methods
	4.4 Results
		4.4.1 Bathymetry and Dredged Samples Description
		4.4.2 Petrographic Analysis
		4.4.3 Whole-Rock Geochemistry (X-Ray Fluorescence, XRF)
		4.4.4 Glass and Mineral Chemistry (Electron Microprobe)
		4.4.5 Geothermobarometry
		4.4.6 Olivine Diffusion Geospeedometry
		4.4.7 Stable Isotopes
		4.4.8 Magnetometry
	4.5 Discussion
		4.5.1 Magmatic Evolution Up to Eruption: Mixing and Differentiation Processes
		4.5.2 Connecting the Location of the Collected Samples with Their Origin at Depth: Pre-versus 2011 Eruptive Events
		4.5.3 Syn-Eruption Magmatic Evolution: Eruptive Styles
	4.6 Conclusions
	4.7 Future Work Over the Next Decade
	Acknowledgements
	References
5 Magma Storage and Migration in El Hierro During the Period 2011–2014
	Abstract
	5.1 Introduction
	5.2 Volcano Monitoring Network in El Hierro
	5.3 Seismic and Geodetic Results
		5.3.1 Pre-eruptive Magma Emplacement (Jul.–Oct. 2011)
		5.3.2 Eruptive Phase (Oct. 2011–Mar. 2012)
		5.3.3 Post-eruptive Magmatic Intrusions (Jun. 2012–Mar. 2014)
	5.4 Discussion
		5.4.1 Comparison of the Unrest Episodes
		5.4.2 Inferences on the Magma Plumbing System
		5.4.3 Lateral Migration of Magma
	5.5 Summary and Open Questions
	References
6 Geophysical, Geodetic and Geochemical Evidence for Precursory Activity: The 2011–2012 Tagoro Submarine Eruption
	Abstract
	6.1 Introduction
	6.2 Precursory Activity in Historical Eruptions in the Canaries
	6.3 Early Signs of Tagoro Volcanic Unrest
	6.4 July–October 2011 Tagoro Volcanic Unrest
	6.5 Very Short-Term Signs of Imminent Eruption
	6.6 Which Precursory Parameters Were Most Relevant for Eruption Forecasting in Tagoro 2011?
	References
7 Geomorphology of Tagoro Volcano Along Eruptive and Posteruptive Phases
	Abstract
	7.1 Introduction
	7.2 Data and Methods
	7.3 Volcanism in the El Hierro Insular Slope
		7.3.1 Physiographic Characteristics
		7.3.2 Spatial Distribution of the Volcanic Edifices
	7.4 Tagoro Evolutive Geomorphology
		7.4.1 Geomorphology Before Eruption
		7.4.2 Morphological Evolution During Eruptive Phase
		7.4.3 Morphological Evolution During Post-eruptive Phase
		7.4.4 Current Geomorphology of the Tagoro Volcano Complex
	7.5 Discussion
		7.5.1 Tagoro Eruptive Evolution Geomorphology
		7.5.2 Tagoro Geomorphology and Processes
		7.5.3 Bathymetric Monitoring
	7.6 Recommendations for Further Geological Underwater Monitoring
	Acknowledgements
	References
The 2011–2014 Volcanic Unrest and Submarine Eruption: Marine Environment
8 Ten Years of Intense Physical–Chemical, Geological and Biological Monitoring Over the Tagoro Submarine Volcano Marine Ecosystem (Eruptive and Degassing Stages)
	Abstract
	8.1 Introduction
	8.2 Ten Years of Intense Physical–Chemical, Geological and Biological Monitoring
	8.3 Dramatic Effects Over the Marine Environment
		8.3.1 Ocean Warming: A Continuous Flux of Energy into the Environment
		8.3.2 Ocean Acidification
		8.3.3 Deoxygenation
		8.3.4 Reduction of the Epipelagic Stocks and A Diel Vertical Migration of Mesopelagic Organisms
		8.3.5 Ocean Discoloration: Remote sensing of Volcanic Processes
			8.3.5.1 Low Resolution Data
			8.3.5.2 Very High Resolution Data
		8.3.6 New Substrates: Annihilation of the Pre-eruptive Biological Communities and Establishment of Chemosynthesis-Based Communities
		8.3.7 Significant Changes in the Surrounding Bacterioplankton Communities
	8.4 An Oasis of Life: Clear Signs of a Marine Ecosystem Recovery
		8.4.1 Ocean Fertilization
		8.4.2 The New Arrival: First Benthonic and Demersal Macro-colonizers
		8.4.3 Microbial Mats: The Discovery of a New Bacterium (Thiolava Veneris)
	8.5 Recommendations for Further Monitoring
	Acknowledgements
	References
9 Tagoro Submarine Volcano as a Natural Source of Significant Dissolved Inorganic Nutrients
	Abstract
	9.1 Introduction
	9.2 Sampling Strategies
	9.3 Nutrient Emissions from Tagoro Volcano
		9.3.1 Silicate
		9.3.2 Phosphate
		9.3.3 Nitrogen Species (NO3−, NO2−, NH4+)
		9.3.4 Iron
	9.4 Extent and Transport of the Emissions
		9.4.1 Eruptive Stage
		9.4.2 Post-eruptive Stage
	9.5 Local Effects by the Nutrient Emissions of Tagoro Volcano
		9.5.1 Nutrient Ratios
		9.5.2 Effects on Local Communities
	9.6 Conclusions and Future Works
	Acknowledgements
	References
10 Microbial Communities Surrounding an Underwater Volcano Near the Island of El Hierro (Canary Islands)
	Abstract
	10.1 Introduction
	10.2 Microbial Communities Around the Tagoro Underwater Volcano
		10.2.1 Abundance and Activity of Microbial Communities in Waters Surrounding the Tagoro Submarine Volcano
		10.2.2 Diversity and Structure of Microbial Communities in Waters, Sediments and Mineral Deposits Surrounding the Tagoro Submarine Volcano
		10.2.3 New Forms of Microbial Life Emerging from the Tagoro Submarine Volcano
	10.3 Concluding Remarks and Future Perspectives
	Acknowledgements
	References
11 Impact of Tagoro Volcano Formation on Benthic Habitats and Associated Biota: A Review
	Abstract
	11.1 Introduction
	11.2 Physical–Chemical Anomalies of the Water Masses During the Eruptive Event and the Successive Recovery Phase
	11.3 Tagoro Formation and Establishment of Chemosynthesis-Based Habitats
	11.4 Impact of Tagoro Formation on Non-chemosynthesis-Based Habitats
	11.5 Habitat Preference by Post-eruptive Benthic and Demersal Colonizing Fauna
	11.6 Impact of Tagoro Formation on the Demersal and Pelagic Megafauna
	11.7 Impact of Tagoro Formation on the Littoral Benthic Communities
	11.8 Recommendations and Further Steps
	Acknowledgements
	References
Volcanism and Society: Cascading Risks and Geoheritage
12 Identification and Management of Indirect Volcanic Risks: Citizens’ Rockfall Observatory on the Island of El Hierro
	Abstract
	12.1 Introduction
	12.2 Rockfalls and the Tagoro Magmatic Unrest
	12.3 Rockfalls Research in El Hierro After the Tagoro Eruption
	12.4 Citizens’ Rockfall Observatory of El Hierro
		12.4.1 Stakeholders and Citizens’ Engagement
		12.4.2 Rockfall Analysis
	12.5 Summary
	Acknowledgements
	References
13 Tagoro, the Youngest Submarine Volcano in the Spanish Geoheritage Inventory: Scientific Value, Geoconservation and Opportunities for Geotourism
	Abstract
	13.1 Introduction
	13.2 Geological Setting
	13.3 Geoheritage Assessment Criteria
	13.4 Assessment of Scientific, Educative and Touristic Values for the Tagoro Submarine Volcanic Eruption
		13.4.1 Scientific Value
		13.4.2 Educational Value
		13.4.3 Tourism Value
	13.5 Actions Proposed to Promote the Public Use of the Tagoro Submarine Geosite
		13.5.1 Environmental Education
		13.5.2 Formal Primary, Secondary and High School Education
		13.5.3 Information and Communication Technologies
		13.5.4 Guided Boat Tours and Scuba Diving in the Tagoro Geosite
	13.6 Tagoro Geosite Challenges and Future Perspectives
	13.7 Summary
	Acknowledgements
	References