Volcanic eruptions are triggered in static dilatational strain fields generated by large earthquakes

Although data catalog analyses have confirmed that volcanic eruptions are triggered by large earthquakes, the triggering mechanism has been under discussion for many decades. In the present study, recent earthquake and volcanic data from the past 35–55 years were analyzed, and it was demonstrated for the first time that the likelihood of new eruptions increases two to three times in the 5–10 years following large earthquakes for volcanoes where the generated static dilatational strain exceeds 0.5 µ, which may, for example, activate gas bubble growth and thereby generate a buoyant force in the magma. In contrast, the eruption likelihood does not increase for volcanoes that are subjected to strong ground motion alone, which affect the magma system and volcanic edifice. These results indicate that we can evaluate the likelihood of triggered eruptions and prepare for new eruptions when a large earthquake occurs.

Knowledge Base of Cenozoic Volcanoes in China

Knowledge management plays an important role in scientific research and provides a basis for technical development in the era of Big Data. Studies of Cenozoic volcanoes in China have been undertaken for more than half a century, generating plentiful relevant literature and data. However, these data have stayed scattered between different authors and libraries, and as such hamper management and access. Based on theories Knowledge Bases and related technologies, we developed the Knowledge Base of Cenozoic Volcanoes (KBCV) to collect such volcanic data in China. The directory tree of the KBCV is structured based on five levels according to the volcano distribution, magma origin, data type, and file format. Data handled by the KBCV supports querying, searching, and browsing. The KBCV can provide well-managed Cenozoic volcanic data and technical support for scientific research and public communication. The KBCV is still in its early stage and is imperfect with respect to data completeness and universalization of the system, and efforts are being made to continuously sophisticate and popularize the system.

Kaboom! Volcano Hazards Mitigation as Government Information

Preparation for an imminent volcanic eruption relies on strategic communication between experts and the general public, ongoing scientific research and monitoring, and government assistance. Should one falter, lives are at stake at the most critical moment, whether it involves inescapable pyroclastic flows or perhaps plane engine shutdown from volcanic ash. Throughout history, legislative concerns surrounding volcano hazards have been built around the notion of proactiveness, yet financial and resource support oftentimes reflect a tendency towards reactiveness. The following document examines the legislative evolution of volcano hazards mitigation that has extended its reach well into 2020. In addition, an overview of the United States Geological Survey’s Volcano Hazards will be followed by an evaluation of government databases for finding historic and current volcanic data and information.

Why quadratic log-log dependence is ubiquitous and what next

Purpose In many real-life situations ranging from financial to volcanic data, growth is described either by a power law – which is linear in log-log scale or by a quadratic dependence in the log-log scale. The purpose of this paper is to explain this empirical fact. Design/methodology/approach The authors use natural scale invariance requirements. Findings In this paper, the authors used natural scale invariance requirement to explain the ubiquity of quadratic log-log dependencies. The authors also explain what to do if quadratic log-log models turn out to be insufficiently accurate. In this case, scale-invariance requirements lead to dependencies which in the log-log scale take cubic, 4th order, etc. form. Originality/value To the best of authors’ knowledge, this is the first theoretical explanation of the empirical quadratic log-log dependence.

Multi-platform volcanological imaging: Two decades of thermal infrared data from the ASTER and MODIS sensors

<p>For the past 20 years, the ASTER and MODIS instruments on Terra have acquired thermal infrared (TIR) data of the world’s volcanoes. These observations have improved our knowledge of long-term volcanic behavior, eruption monitoring, and post-eruption change. MODIS acquires images twice per day (later doubling this after the launch of Aqua) with 1 km TIR and mid-IR resolution. The volcano data from MODIS were later organized into global automated observation programs such as MODVOLC (USA) and later MIROVA (IT). These systems continually detect and track the amount of emitted energy at each active volcano, resulting in vast databases over time that are critically important for ongoing eruptions. Unlike MODIS, ASTER is scheduled and acquires TIR data at 90 m spatial resolution nominally every 5 – 16 days depending on the latitude. This can be improved to hours with proper scheduling and orbital dependencies using its expedited data system. For the past 15 years, an ASTER program called the Urgent Request Protocol (URP) has combined the rapid detection capability of MODIS with the high resolution expedited observations of ASTER in a sensor-web approach. The URP is operated by the University of Pittsburgh in conjunction with (and the support of) the Universities of Alaska, Hawaii, Turin (IT), Clermont Auvergne (FR), and Bristol (UK) as well as the USGS, the LP DAAC and the ASTER science team. The data are used for: operational response to new eruptions; determining thermal trends months prior to an eruption; inferring the emplacement of new lava lobes; and mapping the constituents of volcanic plumes, to name a few. This ASTER TIR archive of volcanic data is now being mined to provide statistics for future TIR orbital concepts being considered by NASA. As TIR instruments get smaller and more numerous with the use of uncooled detectors, they will become CubeSat compatible and could operate in a multi-platform, sensor-web architecture. This would improve response times to volcanic crises and enable new measurements such as the global inventory of volcanic degassing, thermal precursory trends at every volcano, and active flow temperatures at the minute timescale required for predictive flow and hazard assessment models. The combined spatial, spectral and temporal resolutions of ASTER and MODIS enabled a new multi-platform, multi-scale approach to volcanic remote sensing, a model which could be greatly improved depending on future instrument/mission selections.</p>

Estimates of true Polar wander since 300Ma

<p>We investigate true polar wander (TPW) since 300Ma. We construct a hotspot reference frame using an updated list of active hotspots with improved criteria aimed at detecting their depth origin, a compilation of terrestrial volcanic data suspected to reveal hotspot activity, and a set of plate reconstructions, based initially on paleomagnetism corrected with respect to hotspots under the assumption of hotspot fixity. The polar motion curves (representing the motion of the mantle taken as a whole) during the periods t=[0 and 150-170] and [150-170 to 280Ma] roughly aligns along two great circles which poles  are both located close to the equator, with a  longitude differing  by some 50°, and positioned close to an axis passing through the Large Low Shear Velocity Provinces (LLSVPs), and close to the maximum degree 2 geoid high under Africa. The TPW rate is slowly decreasing with respect to time but remains close or below the observed 10cm/yr present value.</p><p>            We compare our TPW data with those obtained from a mantle density heterogeneities model which computes the temporal evolution of the Principal Inertia Axis (PIA).  The minimum PIA is shown to be in agreement with the two poles previously determined, while the maximum PIA  path (which represents the evolution of the geographic pole) displays strong similarities with the observed TPW (directions, cusps). The sudden changes of TPW direction (i.e., cusps) can be explained  by mass reorganizations within the mantle principally linked to changes in subductions, while the domes greatly stabilize the system.</p><p> </p>

Special Issue on Earthquake and Volcano Hazards Observation and Research Program

The Earthquake and Volcano Hazards Observation and Research Program (2014–2018) carried out comprehensive research to mitigate disasters related to earthquakes and volcanic eruptions. The program selected multidisciplinary research in which earth scientists who study the processes of earthquake generation and volcanic eruptions, historians, archaeologists, human and social scientists, and engineers were all involved. The program aimed to collect pre-instrumental and pre-historical earthquake and volcanic data to understand earthquake and volcano disasters, to find risk evaluation techniques, and to evaluate disaster response and preparedness. Active collaborations between researchers from different science fields inspired new ideas and have driven various research in the program. New findings from the program have also created international collaborations and recognitions. Most of the results and new findings in the program have already been published in various internationally recognized journals and have greatly influenced scientific communities. We believe that it is important to compile our findings from the last five years of the program and to publish the essence of our findings and published papers in this special issue. We hope that this special issue will be of value to researchers who are interested in multidisciplinary studies of mitigation of disasters such as earthquakes, volcanic eruptions, and related phenomena.

Earthquake and Volcano Hazards Observation and Research Program: An Overview

The Earthquake and Volcano Hazards Observation and Research Program was from Japanese fiscal year 2014 to 2018. This national program succeeded the Research Program for Earthquake and Volcanic Eruption Prediction (2009–2013). However, mainly because of the disaster caused by the 2011 earthquake off the Pacific coast of Tohoku, known as the 2011 Tohoku Earthquake, the basic policy of the program changed drastically. It changed from research for predicting earthquakes and volcanic eruptions to comprehensive research for mitigating disasters on the basis of scientific results related to the mechanisms of earthquakes and volcanic eruptions and their forecasts. The program was planned to be multidisciplinary in nature. In addition to Earth scientists working to get a scientific understanding of earthquakes and volcanic eruptions, historians, archaeologists, human and social scientists, and engineers took part in the program aimed at collecting pre-instrumental earthquake and volcanic data, understanding earthquake and volcano disasters, risk evaluation, and research into disaster response and preparedness. In this article, we review the basic concept of the 2014–2018 program and its main achievements. In the end, we summarize the problems left for future studies.

The Spatial and Spectral Resolution of ASTER Infrared Image Data: A Paradigm Shift in Volcanological Remote Sensing

During the past two decades, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on the Terra satellite has acquired nearly 320,000 scenes of the world’s volcanoes. This is ~10% of the data in the global ASTER archive. Many of these scenes captured volcanic activity at never before seen spatial and spectral scales, particularly in the thermal infrared (TIR) region. Despite this large archive of data, the temporal resolution of ASTER is simply not adequate to understand ongoing eruptions and assess the hazards to local populations in near real time. However, programs designed to integrate ASTER into a volcanic data sensor web have greatly improved the cadence of the data (in some cases, to as many as 3 scenes in 48 h). This frequency can inform our understanding of what is possible with future systems collecting similar data on the daily or hourly time scales. Here, we present the history of ASTER’s contributions to volcanology, highlighting unique aspects of the instrument and its data. The ASTER archive was mined to provide statistics including the number of observations with volcanic activity, its type, and the average cloud cover. These were noted for more than 2000 scenes over periods of 1, 5 and 20 years.