Geology topics

Peter F. Cervelli

Publications and source records attributed to Peter F. Cervelli.

14 recordsLinked to original sources

USGS2023

Ring fault creep drives volcano-tectonic seismicity during caldera collapse of Kīlauea in 2018

Basaltic caldera collapses are episodic, producing very-long-period (VLP) earthquakes up to M w 5.4, with prolific inter-collapse (between collapses) volcano-tectonic (VT) seismicity. During the 2018 caldera collapse of Kīlauea Volcano, VT seismicity ceased following each collapse, and then accelerated to a quasi-steady rate prior to the next collapse, marking a temporal pattern distinct from typical foreshock/aftershock sequences. There is currently no consensus on the mechanism(s) that generates the VT seismicity. Here we demonstrate that inter-collapse ring fault creep, induced by chamber depressurization, was the main driver of VT seismicity at Kīlauea in 2018. This is evidenced by: 1) the correlation between cumulative number of VT events and GNSS-derived ring fault creep; 2) agreement between repeating earthquake and GNSS derived creep rates; and 3) consistency between the time dependence of mechanically modeled, creep-driven seismicity and observations. We further show that, ring fault creep can be explained by velocity strengthening friction alone or in conjunction with viscous shear zone rheology. The simultaneous occurrence of creep and seismicity highlights the spatially heterogeneous velocity weakening/strengthening friction on the ring fault. If the VT seismicity-creep correlation can be replicated at other basaltic volcanoes, it would demonstrate that VT seismicity can be used as a proxy for ring fault creep in the absence of GNSS measurements on subsiding caldera block(s).

Hawaii↗

USGS2022

The Volcano Hazards Program — Strategic science plan for 2022–2026

The U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) Strategic Science Plan, developed through discussion with scientists-in-charge of the USGS volcano observatories and the director of the USGS Volcano Science Center, specifies six major strategic goals to be pursued over the next 5 years. The purpose of these goals is to help fulfill the USGS VHP mission to enhance public safety and to minimize social and economic disruption caused by volcanic eruptions in the United States and its territories, through delivery of effective forecasts, warnings, and information on volcano hazards based on scientific understanding of volcanic processes. These six major strategic goals are to (1) continue—and when possible, accelerate—implementation of the National Volcano Early Warning System (NVEWS); (2) improve community preparedness for volcanic hazards by updating and standardizing essential components of volcano hazard assessments and providing training to land managers, emergency responders, and State and local communities; (3) develop the next generation of volcano hazard assessments using geographic information systems and other digital tools; (4) make observations with new instrumentation and take advantage of advances in real-time gas sensors; (5) rebuild the Hawaiian Volcano Observatory and its monitoring capabilities; and (6) form new partnerships and strengthen existing partnerships with other government agencies and with academia and industry, to advance volcano monitoring, increase understanding of volcanic processes, and disseminate USGS information. In its effort to advance volcano science and monitoring techniques, the VHP has identified six scientific targets to pursue over the next 5 years, including: (1) increased understanding of volcano seismicity; (2) improved probabilistic forecasting; (3) deepened grasp of volcano eruption histories and geochronology; (4) newly developed and refined physical models of magmatic systems, leading to better situational awareness and accuracy of eruption forecasts; (5) improved warnings and forecasts of volcanic ash and gas clouds and characterization of volcanic smog sources; and (6) refined lava-flow modeling and forecasting of lava-flow paths.

Circular↗

USGS2021

Five-year management plan for establishing and operating NVEWS—The National Volcano Early Warning System

On March 12, 2019, Congress passed the John D. Dingell, Jr., Conservation, Management, and Recreation Act (Public Law 116–9; 133 Stat. 580), in which Title V, §5001 (43 U.S.C. 31k) authorized the establishment of the National Volcano Early Warning and Monitoring System (NVEWS) within the U.S. Geological Survey (USGS). Conceived by the USGS Volcano Hazards Program in 2005, NVEWS is designed to be a proactive, fully integrated national-scale volcano monitoring system to ensure that the 161 potentially active volcanoes in the United States and its territories are monitored at levels commensurate with the threat they pose. The core of this report is the first USGS NVEWS five-year management plan, which was presented to Congress on March 12, 2020, and which details the principal elements of NVEWS that will be developed over the next five years, pending sufficient funding. These elements are improvements and enhancements to the monitoring network, a National Volcano Data Center, an external grants activity, an Advisory Committee, an Implementation Committee, and partnerships, with estimated cost projections and annual milestones.

Northern Mariana Islands↗

USGS2015

Renewed inflation of Long Valley Caldera, California (2011 to 2014)

Slow inflation began at Long Valley Caldera in late 2011, coinciding with renewed swarm seismicity. Ongoing deformation is concentrated within the caldera. We analyze this deformation using a combination of GPS and InSAR (TerraSAR-X) data processed with a persistent scatterer technique. The extension rate of the dome-crossing baseline during this episode (CA99 to KRAC) is 1 cm/yr, similar to past inflation episodes (1990–1995 and 2002–2003), and about a tenth of the peak rate observed during the 1997 unrest. The current deformation is well modeled by the inflation of a prolate spheroidal magma reservoir &sim;7 km beneath the resurgent dome, with a volume change of &sim;6 × 10 6  m 3 /yr from 2011.7 through the end of 2014. The current data cannot resolve a second source, which was required to model the 1997 episode. This source appears to be in the same region as previous inflation episodes, suggesting a persistent reservoir.

California↗

USGS2013

Volcano–ice interactions precursory to the 2009 eruption of Redoubt Volcano, Alaska

In late summer of 2008, after nearly 20 years of quiescence, Redoubt Volcano began to show signs of abnormal heat flow in its summit crater. In the months that followed, the excess heat triggered melting and ablation of Redoubt's glaciers, beginning at the summit and propagating to lower elevations as the unrest accelerated. A variety of morphological changes were observed, including the creation of ice cauldrons, areas of wide-spread subsidence, punctures in the ice carved out by steam, and deposition from debris flows. In this paper, we use visual observations, satellite data, and a high resolution digital elevation model of the volcanic edifice to calculate ice loss at Redoubt as a function of time. Our aim is to establish from this time series a proxy for heat flow that can be compared to other data sets collected along the same time interval. Our study area consists of the Drift glacier, which flows from the summit crater down the volcano's north slope, and makes up about one quarter of Redoubt's total ice volume of ~ 4 km 3 . The upper part of the Drift glacier covers the area of recent volcanism, making this part of ice mass most susceptible to the effect of volcanic heating. Moreover, melt water and other flows are channeled down the Drift glacier drainage by topography, leaving the remainder of Redoubt's ice mantle relatively unaffected. The rate of ice loss averaged around 0.1 m 3 /s over the last four months of 2008, accelerated to over twenty times this value by February 2009, and peaked at greater than 22 m 3 /s, just prior to the first major explosion on March 22, 2009. We estimate a cumulative ice loss over this period of about 35 million cubic meters (M m 3 ).

Alaska↗

USGS2013

Modeling crustal deformation near active faults and volcanic centers: a catalog of deformation models and modeling approaches

This manual provides the physical and mathematical concepts for selected models used to interpret deformation measurements near active faults and volcanic centers. The emphasis is on analytical models of deformation that can be compared with data from the Global Positioning System (GPS) receivers, Interferometric synthetic aperture radar (InSAR), leveling surveys, tiltmeters and strainmeters. Source models include pressurized spherical, ellipsoidal, and horizontal penny-shaped geometries in an elastic, homogeneous, flat half-space. Vertical dikes and faults are described following the mathematical notation for rectangular dislocations in an elastic, homogeneous, flat half-space. All the analytical expressions were verified against numerical models developed by use of COMSOL Multyphics, a Finite Element Analysis software (http://www.comsol.com). In this way, typographical errors present were identified and corrected. Matlab scripts are also provided to facilitate the application of these models.

Techniques and Methods↗

USGS2012

Inflation rates, rifts, and bands in a pāhoehoe sheet flow

The margins of sheet flows—pāhoehoe lavas emplaced on surfaces sloping <2°—are typically delineated by structures that form to accommodate vertical flow inflation. We refer to these structures as inflation rifts. The surfaces of inflation rifts almost always exhibit bands of varying color and texture. Various explanations for the bands have been proposed, but active band formation has never been documented. In order to test our hypothesis that banding is caused by changes in the inflation rate, we collected time-lapse photographs of the margin of an actively inflating flow and simultaneously measured the height of the flow with an extensometer. Data collected over a period of ∼1 d indicate that the height of the flow margin changed in a stepwise manner and that rate changes correlate with band formation. This confirms our hypothesis. Inflation and rift-band formation is probably cyclic, because the pattern we observed suggests episodic or crude cyclic behavior. Furthermore, some inflation rifts contain numerous bands whose spacing and general appearances are remarkably similar. We propose a conceptual model wherein the inferred cyclicity is due to the competition between the fluid pressure in the flow's liquid core and the tensile strength of the viscoelastic layer where it is weakest—in inflation rifts. The viscoelastic layer consists of lava that has cooled to temperatures between 800 and 1070 °C. This layer is the key parameter in our model because, in its absence, rift banding and stepwise changes in the flow height would not occur.

Hawaii↗

USGS2011

The reawakening of Alaska's Augustine volcano

Augustine volcano, in south central Alaska, ended a 20-year period of repose on 11 January 2006 with 13 explosive eruptions in 20 days. Explosive activity shifted to a quieter effusion of lava in early February, forming a new summit lava dome and two short, blocky lava flows by late March (Figure 1). The eruption was heralded by eight months of increasing seismicity, deformation, gas emission, and small phreatic eruptions, the latter consisting of explosions of steam and debris caused by heating and expansion of groundwater due to an underlying heat source.

Alaska↗

USGS2010

Volcano-Monitoring Instrumentation in the United States, 2008

The United States is one of the most volcanically active countries in the world. According to the global volcanism database of the Smithsonian Institution, the United States (including its Commonwealth of the Northern Mariana Islands) is home to about 170 volcanoes that are in an eruptive phase, have erupted in historical time, or have not erupted recently but are young enough (eruptions within the past 10,000 years) to be capable of reawakening. From 1980 through 2008, 30 of these volcanoes erupted, several repeatedly. Volcano monitoring in the United States is carried out by the U.S. Geological Survey (USGS) Volcano Hazards Program, which operates a system of five volcano observatories-Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Hawaiian Volcano Observatory (HVO), Long Valley Observatory (LVO), and Yellowstone Volcano Observatory (YVO). The observatories issue public alerts about conditions and hazards at U.S. volcanoes in support of the USGS mandate under P.L. 93-288 (Stafford Act) to provide timely warnings of potential volcanic disasters to the affected populace and civil authorities. To make efficient use of the Nation's scientific resources, the volcano observatories operate in partnership with universities and other governmental agencies through various formal agreements. The Consortium of U.S. Volcano Observatories (CUSVO) was established in 2001 to promote scientific cooperation among the Federal, academic, and State agencies involved in observatory operations. Other groups also contribute to volcano monitoring by sponsoring long-term installation of geophysical instruments at some volcanoes for specific research projects. This report describes a database of information about permanently installed ground-based instruments used by the U.S. volcano observatories to monitor volcanic activity (unrest and eruptions). The purposes of this Volcano-Monitoring Instrumentation Database (VMID) are to (1) document the Nation's existing, ground-based, volcano-monitoring capabilities, (2) answer queries within a geospatial framework about the nature of the instrumentation, and (3) provide a benchmark for planning future monitoring improvements. The VMID is not an archive of the data collected by monitoring instruments, nor is it intended to keep track of whether a station is temporarily unavailable due to telemetry or equipment problems. Instead, it is a compilation of basic information about each instrument such as location, type, and sponsoring agency. Typically, instruments installed expressly for volcano monitoring are emplaced within about 20 kilometers (km) of a volcanic center; however, some more distant instruments (as far away as 100 km) can be used under certain circumstances and therefore are included in the database. Not included is information about satellite-based and airborne sensors and temporarily deployed instrument arrays, which also are used for volcano monitoring but do not lend themselves to inclusion in a geospatially organized compilation of sensor networks. This Open-File Report is provided in two parts: (1) an Excel spreadsheet (http://pubs.usgs.gov/of/2009/1165/) containing the version of the Volcano-Monitoring Instrumentation Database current through 31 December 2008 and (2) this text (in Adobe PDF format), which serves as metadata for the VMID. The disclaimer for the VMID is in appendix 1 of the text. Updated versions of the VMID will be posted on the Web sites of the Consortium of U.S. Volcano Observatories (http://www.cusvo.org/) and the USGS Volcano Hazards Program http://volcanoes.usgs.gov/activity/data/index.php.

Alaska, Arizona, California, Colorado, Hawaii, New↗

USGS2010

Geodetic constraints on magma movement and withdrawal during the 2006 eruption of Augustine Volcano: Chapter 17 in The 2006 eruption of Augustine Volcano, Alaska

For the first time in the United States, a modern geodetic network of continuously recording Global Positioning System (GPS) receivers has measured a complete eruption cycle at a stratovolcano, Augustine Volcano in Alaska, from the earliest precursory unrest through the return to background quiescence. The on-island network consisted of five continuously recording, telemetered GPS stations, four continuously recording, nontelemetered stations, and about 10 campaign bench marks. The continuous network recorded several distinct and conspicuous signals over the course of the unrest and eruption, starting with a months-long precursory inflation centered beneath the volcano at around sea level. Nearly coincident with the highest volumetric eruption rates, this inflation gave way to a more deep seated deflation that we interpret as a major withdrawal (approx. 25 million m3 of compressed magma) from a nearly cylindrical magma reservoir centered about 5 km below sea level. Detailed analysis of the geodetic time series reveals additional nuance, including the probable upward propagation of a small dike into the edifice in the 60 days or so before the onset of large-scale explosive activity. Comparisons of the geodetic data and their resulting interpretations with other data, such as earthquake hypocenters and petrologically inferred magma-pressure histories, reveal a kinematic, if not mechanical, account of the 2006 eruption that details the shape and location of the magma source region, the means and velocity of magma transport, and the establishment of a short lived volume- (or pressure-) buffering capability held within the magma reservoir. The cumulative deformation over the course of the eruption shows a large signal close in and high on the edifice that decays rapidly with distance. This pattern indicates a small permanent increase in the edifice volume (beyond that added by the surficial lava dome) but also shows that without close-in (<2.5 km from the summit) stations, the eruption might have been invisible to campaign GPS stations alone.

Alaska↗

USGS2008

Remote-controlled pan, tilt, zoom cameras at Kilauea and Mauna Loa Volcanoes, Hawai'i

Lists of important volcano-monitoring disciplines usually include seismology, geodesy, and gas geochemistry. Visual monitoring - the essence of volcanology - is usually not mentioned. Yet, observations of the outward appearance of a volcano provide data that is equally as important as that provided by the other disciplines. The eye was almost certainly the first volcano monitoring-tool used by early man. Early volcanology was mostly descriptive and was based on careful visual observations of volcanoes. There is still no substitute for the eye of an experienced volcanologist. Today, scientific instruments replace or augment our senses as monitoring tools because instruments are faster and more sensitive, work tirelessly day and night, keep better records, operate in hazardous environments, do not generate lawsuits when damaged or destroyed, and in most cases are cheaper. Furthermore, instruments are capable of detecting phenomena that are outside the reach of our senses. The human eye is now augmented by the camera. Sequences of timed images provide a record of visual phenomena that occur on and above the surface of volcanoes. Photographic monitoring is a fundamental monitoring tool; image sequences can often provide the basis for interpreting other data streams. Monitoring data are most useful when they are generated and are available for analysis in real-time or near real-time. This report describes the current (as of 2006) system for real-time photograph acquisition and transmission from remote sites on Kilauea and Mauna Loa volcanoes to the U.S. Geological Survey Hawaiian Volcano Observatory (HVO). It also describes how the photographs are archived and analyzed. In addition to providing system documentation for HVO, we hope that the report will prove useful as a practical guide to the construction of a high-bandwidth network for the telemetry of real-time data from remote locations.

Hawai'i↗

USGS2007

Technical-information products for a National Volcano Early Warning System

Technical outreach — distinct from general-interest and K-12 educational outreach — for volcanic hazards is aimed at providing usable scientific information about potential or ongoing volcanic activity to public officials, businesses, and individuals in support of their response, preparedness, and mitigation efforts. Within the context of a National Volcano Early Warning System (NVEWS) (Ewert et al., 2005), technical outreach is a critical process, transferring the benefits of enhanced monitoring and hazards research to key constituents who have to initiate actions or make policy decisions to lessen the hazardous impact of volcanic activity. This report discusses recommendations of the Technical-Information Products Working Group convened in 2006 as part of the NVEWS planning process. The basic charge to the Working Group was to identify a web-based, volcanological "product line" for NVEWS to meet the specific hazard-information needs of technical users. Members of the Working Group were: Marianne Guffanti (Chair), USGS, Reston VA Steve Brantley, USGS, Hawaiian Volcano Observatory HI Peter Cervelli, USGS, Alaska Volcano Observatory, Anchorage AK Chris Nye, Division of Geological and Geophysical Surveys and Alaska Volcano Observatory, Fairbanks AK George Serafino, National Oceanic and Atmospheric Administration, Camp Springs MD Lee Siebert, Smithsonian Institution, Washington DC Dina Venezky, USGS, Volcano Hazards Team, Menlo Park CA Lisa Wald, USGS, Earthquake Hazards Program, Golden CO

Open-File Report↗

USGS2006

Growth and collapse of Hawaiian volcanoes

This special issue is an outgrowth of a session of the same name held at the 2003 Fall Meeting of the American Geophysical Union (AGU) in San Francisco. The session served dual purposes: to highlight recent advances in our understanding of the development and internal structure of Hawaiian volcanoes, and to recognize the important contributions of James Moore to this field of study.

Hawai'i↗

USGS2006

Earthquakes triggered by silent slip events on Kīlauea volcano, Hawaii

Slow-slip events, or ‘silent earthquakes’, have recently been discovered in a number of subduction zones including the Nankai trough 1, 2, 3 in Japan, Cascadia 4, 5 , and Guerrero 6 in Mexico, but the depths of these events have been difficult to determine from surface deformation measurements. Although it is assumed that these silent earthquakes are located along the plate megathrust, this has not been proved. Slow slip in some subduction zones is associated with non-volcanic tremor 7, 8 , but tremor is difficult to locate and may be distributed over a broad depth range 9 . Except for some events on the San Andreas fault 10 , slow-slip events have not yet been associated with high-frequency earthquakes, which are easily located. Here we report on swarms of high-frequency earthquakes that accompany otherwise silent slips on K ī lauea volcano, Hawaii. For the most energetic event, in January 2005, the slow slip began before the increase in seismicity. The temporal evolution of earthquakes is well explained by increased stressing caused by slow slip, implying that the earthquakes are triggered. The earthquakes, located at depths of 7–8   km, constrain the slow slip to be at comparable depths, because they must fall in zones of positive Coulomb stress change. Triggered earthquakes accompanying slow-slip events elsewhere might go undetected if background seismicity rates are low. Detection of such events would help constrain the depth of slow slip, and could lead to a method for quantifying the increased hazard during slow-slip events, because triggered events have the potential to grow into destructive earthquakes.

Nature↗