Earthscope was an
National Science Foundation
The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I ...
(NSF) funded
earth science
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres ...
program that, from 2003-2018, used geological and geophysical techniques to explore the structure and evolution of the
North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
n continent and to understand the processes controlling earthquakes and
volcanoes
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates are ...
.
The project had three components:
USArray
USArray is one of the three components of the Earthscope project he other two being the Plate Boundary Observatory (PBO) and the San Andreas Fault Observatory at Depth (SAFOD), funded by the National Science Foundation and being constructed, opera ...
, the
Plate Boundary Observatory The Plate Boundary Observatory (PBO) was the geodetic component of the EarthScope Facility. EarthScope was an earth science program that explored the 4-dimensional structure of the North American Continent. EarthScope (and PBO) was a 15-year project ...
, and the
San Andreas Fault Observatory at Depth
The San Andreas Fault Observatory at Depth (SAFOD) is a research project that began in 2002 aimed at collecting geological data about the San Andreas Fault for the purpose of predicting and analyzing future earthquakes. The site consists of a p ...
. Organizations associated with the project included
UNAVCO
UNAVCO is a non-profit university-governed consortium that facilitates geoscience research and education using Geodesy. UNAVCO is funded by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) to supp ...
, the
Incorporated Research Institutions for Seismology
IRIS (Incorporated Research Institutions for Seismology) is a university research consortium dedicated to exploring the Earth's interior through the collection and distribution of seismographic data. IRIS programs contribute to scholarly research, ...
(IRIS),
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...
, the
United States Geological Survey
The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...
(USGS) and
National Aeronautics and Space Administration
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding th ...
(NASA). Several international organizations also contributed to the initiative. EarthScope data are publicly accessible.
Observatories
There are three EarthScope observatories: the
San Andreas Fault Observatory at Depth
The San Andreas Fault Observatory at Depth (SAFOD) is a research project that began in 2002 aimed at collecting geological data about the San Andreas Fault for the purpose of predicting and analyzing future earthquakes. The site consists of a p ...
(SAFOD), the
Plate Boundary Observatory The Plate Boundary Observatory (PBO) was the geodetic component of the EarthScope Facility. EarthScope was an earth science program that explored the 4-dimensional structure of the North American Continent. EarthScope (and PBO) was a 15-year project ...
(PBO), and the
Seismic and Magnetotelluric Observatory (USArray). These observatories consist of
boreholes
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petrol ...
into an
active fault
An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,0 ...
zone,
global positioning system
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS) receivers,
tiltmeter
A tiltmeter is a sensitive inclinometer designed to measure very small changes from the vertical level, either on the ground or in structures. Tiltmeters are used extensively for monitoring volcanoes, the response of dams to filling, the small m ...
s, long-baseline laser
strainmeters, borehole strainmeters, permanent and portable
seismographs
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output ...
, and
magnetotelluric
Magnetotellurics (MT) is an electromagnetic geophysical method for inferring the earth's subsurface electrical conductivity from measurements of natural geomagnetic and geoelectric field variation at the Earth's surface.
Investigation depth ra ...
stations. The various EarthScope components will provide integrated and highly accessible data on
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is pr ...
and
thermochronology
Thermochronology is the study of the thermal evolution of a region of a planet. Thermochronologists use radiometric dating along with the closure temperatures that represent the temperature of the mineral being studied at the time given by the dat ...
,
petrology
Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...
and
geochemistry
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the e ...
, structure and
tectonics
Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents k ...
, surficial processes and
geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or n ...
,
geodynamic
Geodynamics is a subfield of geophysics dealing with dynamics (physics), dynamics of the Earth. It applies physics, chemistry and mathematics to the understanding of how mantle convection leads to plate tectonics and geologic phenomena such as sea ...
modeling,
rock physics
Petrophysics (from the Greek πέτρα, ''petra'', "rock" and φύσις, ''physis'', "nature") is the study of physical and chemical rock properties and their interactions with fluids.
A major application of petrophysics is in studying reservoi ...
, and
hydrogeology
Hydrogeology (''hydro-'' meaning water, and ''-geology'' meaning the study of the Earth) is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust (commonly in aquif ...
.
Seismic and Magnetotelluric Observatory (USArray)
USArray, managed by IRIS, is a 15-year program to place a dense network of permanent and portable seismographs across the continental United States. These seismographs record the seismic waves released by earthquakes that occur around the world.
Seismic waves
A seismic wave is a wave of acoustic energy that travels through the Earth. It can result from an earthquake, volcanic eruption, magma movement, a large landslide, and a large man-made explosion that produces low-frequency acoustic energy. S ...
are indicators of energy disbursement within the earth. By analyzing the records of earthquakes obtained from this dense grid of seismometers, scientists can learn about Earth structure and dynamics and the physical processes controlling earthquakes and volcanoes. The goal of USArray is primarily to gain a better understanding of the structure and evolution of the
continental crust
Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...
,
lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust (geology), crust and the portion of the upper mantle (geology), mantle that behaves elastically on time sca ...
, and
mantle
A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that.
Mantle may refer to:
*Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear
**Mantle (vesture), an Eastern Orthodox ve ...
underneath North America.
The USArray is composed of four facilities: a Transportable Array, a Flexible Array, a Reference Network, and a Magnetotelluric Facility.
The Transportable Array is composed of 400 seismometers that are being deployed in a rolling grid across the United States over a period of 10 years. The stations are placed 70 km apart, and can map the upper 70 km of the Earth. After approximately two years, stations are moved east to the next site on the grid – unless adopted by an organization and made a permanent installation. Once the sweep across the United States is completed, over 2000 locations will have been occupied. The
Array Network Facility
The Array Network Facility component of the EarthScope USArray project is charged with ensuring all the real time seismic data collected from the Transportable Array and Flexible Arrays are transmitted, checked for quality, archived, and accessible ...
is responsible for data collection from the Transportable Array stations.
The Flexible Array is composed of 291 broadband stations, 120 short period stations, and 1700 active source stations. The Flexible Array allows sites to be targeted in a more focused manner than the broad Transportable Array. Natural or artificially created seismic waves can be used to map structures in the Earth.
The Reference Network is composed of permanent seismic stations spaced about 300 km apart. The Reference Network provides a baseline for the Transportable Array and Flexible Array. EarthScope added and upgraded 39 stations to the already existing
Advanced National Seismic System
The Advanced National Seismic System (ANSS) is a collaboration of the U.S. Geological Survey (USGS) and regional, state, and academic partners that collects and analyzes data on significant earthquakes to provide near real-time (generally within 10 ...
, which is part of the Reference Network.
The Magnetotelluric Facility is composed of seven permanent and 20 portable sensors that record
electromagnetic field
An electromagnetic field (also EM field or EMF) is a classical (i.e. non-quantum) field produced by (stationary or moving) electric charges. It is the field described by classical electrodynamics (a classical field theory) and is the classical c ...
s. It is the electromagnetic equivalent of the seismic arrays. The portable sensors are moved in a rolling grid similar to the Transportable Array grid, but are only in place about a month before they are moved to the next location. A magnetotelluric station consists of a
magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
, four
electrodes
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials de ...
, and a data recording unit that are buried in shallow holes. The electrodes are oriented north-south and east-west and are saturated in a salt solution to improve conductivity with the ground.
Plate Boundary Observatory (PBO)
The Plate Boundary Observatory PBO consists of a series of
geodetic
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...
instruments, Global Positioning System (GPS) receivers and borehole strainmeters, that have been installed to help understand the boundary between the
North American Plate
The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...
and
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate.
The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Iza ...
. The PBO network includes several major observatory components: a network of 1100 permanent, continuously operating
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS) stations many of which provide data at high-rate and in real-time, 78 borehole
seismometers
A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output ...
, 74 borehole strainmeters, 26 shallow borehole tiltmeters, and six long baseline laser strainmeters. These instruments are complemented by InSAR (
interferometric synthetic aperture radar Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing. This geodetic method uses two or more synthetic aperture radar (SAR) radar imaging, images to generate maps o ...
) and LiDAR (
light detection and ranging
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
) imagery and
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is pr ...
acquired as part of the GeoEarthScope initiative. PBO also includes comprehensive data products, data management and education and outreach efforts. These permanent networks are supplemented by a pool of portable
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
receivers that can be deployed for temporary networks to researchers, to measure the crustal motion at a specific target or in response to a geologic event. The Plate Boundary Observatory portion of EarthScope is operated by
UNAVCO
UNAVCO is a non-profit university-governed consortium that facilitates geoscience research and education using Geodesy. UNAVCO is funded by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) to supp ...
, Inc. UNAVCO is a non-profit, university-governed consortium that facilitates research and education using
geodesy
Geodesy ( ) is the Earth science of accurately measuring and understanding Earth's figure (geometric shape and size), orientation in space, and gravity. The field also incorporates studies of how these properties change over time and equivale ...
.
San Andreas Fault Observatory at Depth (SAFOD)
The San Andreas Fault Observatory at Depth (SAFOD) consists of a main borehole that cuts across the active
San Andreas Fault
The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonics, tectonic boundary between the Pacific Plate and the North American Plate, and its motion is Fault (geology)#Strike-slip fau ...
at a depth of approximately 3 km and a pilot hole about 2 km southwest of San Andreas Fault. Data from the instruments installed in the holes, which consist of
geophone
A geophone is a device that converts ground movement (velocity) into voltage, which may be recorded at a recording station. The deviation of this measured voltage from the base line is called the seismic response and is analyzed for structure of ...
sensors, data acquisition systems, and GPS clocks, as well as samples collected during drilling, will help to better understand the processes that control the behavior of the San Andreas Fault.
Data Products
Data collected from the various observatories are used to create different types of data products. Each data product addresses a different scientific problem.
P-Wave Tomography
Tomography
Tomography is imaging by sections or sectioning that uses any kind of penetrating wave. The method is used in radiology, archaeology, biology, atmospheric science, geophysics, oceanography, plasma physics, materials science, astrophysics, quantu ...
is a method of producing a three-dimensional image of the internal structures of a solid object (such as the human body or the earth) by the observation and recording of differences in the effects on the passage of energy waves impinging on those structures. The waves of energy are P-waves generated by earthquakes and are recording the wave velocities. The high quality data that is being collected by the permanent seismic stations of USArray and the Advanced National Seismic System (ANSS) will allow the creation of high resolution seismic imaging of the Earth's interior below the United States. Seismic tomography helps constrain mantle velocity structure and aids in the understanding of chemical and geodynamic processes that are at work. With the use of the data collected by USArray and global travel-time data, a global tomography model of P-wave velocity heterogeneity in the mantle can be created. The range and resolution of this technique will allow investigation into the suite of problems that are of concern in the North American mantle lithosphere, including the nature of the major tectonic features. This method gives evidence for differences in thickness and the velocity anomaly of the
mantle lithosphere
A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that.
Mantle may refer to:
* Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear
**Mantle (vesture), an Eastern Orthodox v ...
between the stable center of the continent and the more active western North America. This data is vital for the understanding of local lithosphere evolution, and when combined with additional global data, will allow the mantle to be imaged beyond the current extent of USArray.
Receiver Reference Models
EarthScope Automated Receiver Survey (EARS), has created a prototype of a system that will be used to address several key elements of the production of EarthScope products. One of the prototype systems is the receiver reference model. It will provide crustal thickness and average crustal Vp/Vs ratios beneath USArray transportable array stations.
Ambient Seismic Noise
The main function of the Advanced National Seismic System (ANSS) and USArray, is to provide high quality data for earthquake monitoring, source studies and Earth structure research. The utility of seismic data is greatly increased when noise levels, unwanted vibrations, are reduced; however broadband seismograms will always contain a certain level of noise. The dominant sources of noise are either from the instrumentation itself or from ambient Earth vibrations. Normally, seismometer self noise will be well below the seismic noise level, and every station will have a characteristic noise pattern that can be calculated or observed. Sources of
seismic noise In geophysics, geology, civil engineering, and related disciplines, seismic noise is a generic name for a relatively persistent vibration of the ground, due to a multitude of causes, that is often a non-interpretable or unwanted component of signal ...
within the Earth are caused by any of the following: the actions of human beings at or near the surface of the Earth, objects moved by wind with the movement being transferred to the ground, running water (river flow), surf, volcanic activity, or long period tilt due to thermal instabilities from poor station design.
A new approach to seismic noise studies will be introduced with the EarthScope project, in that there are no attempts to screen the continuous waveforms to eliminate body and
surface waves
In physics, a surface wave is a mechanical wave that propagates along the interface between differing media. A common example is gravity waves along the surface of liquids, such as ocean waves. Gravity waves can also occur within liquids, at th ...
from the naturally occurring earthquakes. Earthquake signals are not generally included in the processing of noise data, because they are generally low probability occurrences, even at low power levels. The two objectives behind the collection of the seismic noise data are to provide and document a standard method to calculate ambient seismic background noise, and to characterize the variation of ambient background seismic noise levels across the United States as a function of
geography
Geography (from Greek: , ''geographia''. Combination of Greek words ‘Geo’ (The Earth) and ‘Graphien’ (to describe), literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and ...
, season, and time of day. The new statistical approach will provide the ability to compute probability density functions (PDFs) to evaluate the full range of noise at a given seismic station, allowing the estimation of noise levels over a broad range of frequencies from 0.01–16 Hz (100-0.0625s period). With the use of this new method it will be much easier to compare seismic noise characteristics between different networks in different regions.
Earthquake Ground Motion Animations
Seismometers of USArray transportable array record the passage of numerous seismic waves through a given point near the Earth's surface, and classically these seismograms are analyzed to deduce properties of the Earth's structure and the seismic source. Given a spatially dense set of seismic recordings, these signals can also be used to visualize the actual continuous seismic waves, providing new insights and interpretation techniques into complex wave propagation effects. Using signals recorded by the array of seismometers, the EarthScope project will be able to animate seismic waves as they sweep across the USArray transportable array for selected larger earthquakes. This will be able to illustrate the regional and teleseismic wave propagation phenomena. The seismic data collected from both permanent and transportable seismic stations will be used to provide these computer generated animations.
Regional Moment Tensors
The seismic moment tensor is one of the fundamental parameters of earthquakes that can be determined from seismic observations. It is directly related to earthquake fault orientation and rupture direction. The
moment magnitude
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...
, Mw derived from the moment tensor magnitude, is the most reliable quantity for comparing and measuring the size of an earthquake with other earthquake magnitudes. Moment tensors are used in a wide range of seismological research fields, such as earthquake statistics, earthquake scaling relationships, and stress inversion. The creation of regional moment tensor solutions, with the appropriate software, for moderate-to-large earthquakes in the U.S. will be from USArray transportable array and Advance National Seismic System broadband seismic stations. Results are obtained in the time and the frequency domain. Waveform fit and amplitude-phase match figures are provided to allow users to evaluate moment tensor quality.
Geodetic Monitoring of the Western US and Hawaii
Global Positioning System (GPS) equipment and techniques provide a unique opportunity for earth scientists to study regional and local tectonic plate motions and conduct natural hazards monitoring. Cleaned network solutions from several GPS arrays have merged into regional clusters in conjunction with the EarthScope project. The arrays include the Pacific Northwest Geodetic Array, EarthScope's Plate Boundary Observatory, the Western Canadian Deformation Array, and networks run by the US Geological Survey. The daily GPS measurements from ~1500 stations along the Pacific/North American
plate boundary
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
provide millimeter-scale accuracy and can be used monitor the displacements of the earths crust. With the use of data modeling software and the recorded GPS data, the opportunity to quantify crustal deformation caused by
plate tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
, earthquakes,
landslides
Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, ...
and volcanic eruptions will be possible.
Time-dependent Strain
The goal is to provide models of time-dependent strain associated with a number of recent earthquakes and other geologic events as constrained by GPS data. With the use of
InSAR Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing. This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface defo ...
(Interferometric Synthetic Aperture Radar), a remote-sensing technique, and PBO (Plate Boundary Observatory), a fixed array of GPS receivers and strainmeters, the EarthScope project will provide spatially continuous strain measurements over wide geographic areas with decimeter to centimeter resolution.
Global Strain Rate Map
The Global Strain Rate Map (GSRM) is a project of the International Lithosphere Program whose mission is to determine a globally self-consistent strain rate and velocity field model, consistent with geodetic and geologic field observations collected by GPS, seismometers, and strainometers. GSRM is a digital model of the global velocity gradient tensor field associated with the accommodation of present-day crustal motions. The overall mission also includes: (1) contributions of global, regional, and local models by individual researchers; (2) archive existing data sets of geologic, geodetic, and seismic information that can contribute toward a greater understanding of strain phenomena; and (3) archive existing methods for modeling strain rates and strain transients. A completed global strain rate map will provide a large amount of information which will contribute to the understanding of continental dynamics and for the quantification of seismic hazards.
Science
There are seven topics that EarthScope will address with the use of the observatories.
Convergent Margin Processes
![Active Margin](https://upload.wikimedia.org/wikipedia/commons/2/29/Active_Margin.svg)
Convergent margins, also known as
convergent boundaries
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...
, are active regions of deformation between two or more
tectonic plates
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
colliding with one another. Convergent margins create areas of
tectonic uplift
Tectonic uplift is the geologic uplift of Earth's surface that is attributed to plate tectonics. While isostatic response is important, an increase in the mean elevation of a region can only occur in response to tectonic processes of crustal thick ...
, such as
mountain ranges
A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...
or volcanoes. EarthScope is focusing on the boundary between the Pacific Plate and the North American Plate in the western United States. EarthScope will provide GPS geodetic data, seismic images, detailed seismicity, magnetotelluric data,
InSAR Interferometric synthetic aperture radar, abbreviated InSAR (or deprecated IfSAR), is a radar technique used in geodesy and remote sensing. This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface defo ...
, stress field maps,
digital elevation model
A digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete gl ...
s, baseline geology, and
paleoseismology
Paleoseismology looks at geologic sediments and rocks, for signs of ancient earthquakes. It is used to supplement seismic monitoring, for the calculation of seismic hazard. Paleoseismology is usually restricted to geologic regimes that have u ...
for a better understanding of convergent margin processes.
A few questions hoping to be answered by EarthScope include:
* What controls the lithospheric architecture?
* What controls the locus of volcanism?
* How do convergent margin processes contribute to growth of the continent through time?
Crustal Strain and Deformation
Crustal
strain
Strain may refer to:
Science and technology
* Strain (biology), variants of plants, viruses or bacteria; or an inbred animal used for experimental purposes
* Strain (chemistry), a chemical stress of a molecule
* Strain (injury), an injury to a mu ...
and
deformation
Deformation can refer to:
* Deformation (engineering), changes in an object's shape or form due to the application of a force or forces.
** Deformation (physics), such changes considered and analyzed as displacements of continuum bodies.
* Defo ...
is the change in shape and volume of continental and oceanic crust caused by stress applied to rock through tectonic forces. An array of variables including composition, temperature, pressure, etc., determines how the crust will deform.
A few questions hoping to be answered by EarthScope include:
* How do crust and mantle
rheology
Rheology (; ) is the study of the flow of matter, primarily in a fluid ( liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an appl ...
vary with rock type and with depth?
* How does lithospheric rheology change in the vicinity of a fault zone?
* What is the distribution of stress in the lithosphere?
Continental Deformation
Continental deformation is driven by plate interactions through active tectonic processes such as continental transform systems with extensional, strike-slip, and contractional regimes. EarthScope will provide velocity field data, portable and continuous GPS data, fault-zone drilling and sampling, reflection seismology, modern seismicity, pre-
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...
seismicity, and magnetotelluric and potential field data for a better understanding of continental deformation.
A few questions hoping to be answered by EarthScope include:
* What are the fundamental controls on deformation of the continent?
* What is the strength profile(s) of the lithosphere?
* What defines tectonic regimes within the continent?
Continent Structure and Evolution
Earth's continents are compositionally distinct from the oceanic crust. The continents record four billion years of geologic history, while the oceanic crust gets recycled about every 180 million years. Because of the age of continental crusts, the ancient structural evolution of the continents can be studied. Data from EarthScope will be used to find the mean seismic structure of the continental crust, associated mantle, and crust-mantle transition. Variability in that structure will also be studied. EarthScope will attempt to define continental lithosphere formation and continent structure and to identify the relationship between continental structure and deformation.
A few questions hoping to be answered by EarthScope include:
* How does magmatism modify, enlarge, and deform continental lithosphere?
* How are the crust and lithospheric mantle related?
* What is the role of extension,
orogenic
Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumpl ...
collapse, and
rifting
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics.
Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...
in constructing the continents?
Faults and Earthquake Processes
EarthScope is acquiring 3D and 4D data that will give scientists a more detailed insight into faulting and earthquakes than ever before. This project is providing a much needed data upgrade from work done in previous years thanks to many technological advances. New data will enable an improved study and understanding of faults and earthquakes that will increase our knowledge of the complete earthquake process, allowing for the continued development of building predictive models. Detailed information on internal fault zone architecture, crust and upper mantle structure, strain rates, and transitions between fault systems and deformation types; as well as heat flow, electromagnetic/magnetotelluric, and seismic waveform data, will all be made available.
A few questions hoping to be answered by EarthScope include:
* How does strain accumulate and release at plate boundaries and within the North American plate?
* How do earthquakes start, rupture, and stop?
* What is the absolute strength of faults and the surrounding lithosphere?
Deep Earth Structure
Through the use of seismology, scientists will be able to collect and evaluate data from the deepest parts of our planet, from the continental lithosphere down to the core. The relationship between lithospheric and the upper mantle processes is something that is not completely known, including upper mantle processes below the United States and their effects on the continental lithosphere. There are many issues of interest, such as determining the source of forces originating in the upper mantle and their effects on the continental lithosphere. Seismic data will also give scientists more understanding and insight into the lower mantle and the Earth's core, as well as activity at the
core-mantle boundary.
A few questions hoping to be answered by EarthScope include:
* How is evolution of the continents linked to processes in the upper mantle?
* What is the level of heterogeneity in the mid-mantle?
* What is the nature and heterogeneity of the lower mantle and core-mantle boundary?
Fluids and Magmas
EarthScope hopes to provide a better understanding of the physics of fluids and magmas in active volcanic systems in relation to the deep Earth and how the evolution of continental lithosphere is related to
upper mantle
The upper mantle of Earth is a very thick layer of rock inside the planet, which begins just beneath the crust (at about under the oceans and about under the continents) and ends at the top of the lower mantle at . Temperatures range from appro ...
processes. The basic idea of how the various melts are formed is known, but not the volumes and rates of
magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
production outside of
Mid-ocean ridge basalts. EarthScope will provide seismic data and tomographic images of the mantle to better understand these processes.
A few questions hoping to be answered by EarthScope include:
* Over what temporal and spatial scales do earthquake deformation and volcanic eruptions couple?
* What controls eruption style?
* What are the predictive signs of imminent volcanic eruption? What are the structural,
rheological
Rheology (; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applie ...
, and chemical controls on fluid flow in the crust?
Education and Outreach
The Education and Outreach Program is designed to integrate EarthScope into both the classroom and the community. The program must reach out to scientific educators and students as well as industry professionals (engineers, land/resource managers, technical application/data users), partners of the project (
UNAVCO
UNAVCO is a non-profit university-governed consortium that facilitates geoscience research and education using Geodesy. UNAVCO is funded by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA) to supp ...
, IRIS, USGS, NASA, etc.), and the general public. To accomplish this, the EOP offers a wide array of educational workshops and seminars, directed at various audiences, to offer support on data interpretation and implementation of data products into the classroom. Their job is to make sure that everyone understands what EarthScope is, what it is doing in the community, and how to use the data it is producing. By generating new research opportunities for students in the scientific community, the program also hopes to expand recruitment for future generations of earth scientists.
Mission
"To use EarthScope data, products, and results to create a measurable and lasting change on the way that Earth science is taught and perceived in the United States."
Goals
* Create a high-profile public identity for EarthScope that emphasizes the integrated nature of the scientific discoveries and the importance of EarthScope research initiatives.
* Establish a sense of ownership among scientific, professional, and educational communities and the public so that a diverse group of individuals and organizations can and will make contributions to EarthScope.
* Promote
science literacy
Scientific literacy or science literacy encompasses written, numerical, and digital literacy as they pertain to understanding science, its methodology, observations, and theories. Scientific literacy is chiefly concerned with an understanding ...
and understanding of EarthScope among all audiences through informal education venues.
* Advance formal Earth science education by promoting inquiry-based classroom investigations that focus on understanding Earth and the interdisciplinary nature of EarthScope.
* Encourage use of EarthScope data, discoveries, and new technology in resolving challenging problems and improving our quality of life.
EarthScope In the Classroom
Education and outreach will be developing tools for educators and students across the United States to interpret and apply this information for solving a wide range of scientific issues within the earth sciences. The project tailors its products to the specified needs and requests of educators.
K-12 Education
One tool that has already been put into action is the EarthScope Education and Outreach Bulletin. The bulletin, targeted for grades 5-8, summarizes a volcanic or tectonic event documented by EarthScope and puts it into an easily interpretable format, complete with diagrams and 3D models. They follow specific content standards based on what a child should be learning at those grade levels. Another is the EarthScope Voyager, Jr. which allows students to explore and visualize the various types of data that are being collected. In this interactive map, the user can add various types of base maps, features, and plate velocities. Educators have access to real time GPS data of plate movement and influences through the UNAVCO website.
University Level
EarthScope promises to produce a large amount of geological and geophysical data that will open the door for numerous research opportunities in the scientific community. As the USArray Big Foot project moves across the country, universities are adopting seismic stations near their areas. These stations are then monitored and maintained by not only the professors, but their students as well. Scouting for future seismic station locations has created field work opportunities for students. The influx of data has already begun creating projects for undergraduate research, master's thesis, and doctoral dissertations. A list of currently funded proposals can be found on the NSF website.
Legacy
Many applications for EarthScope data currently exist, as mentioned above, and many more will arise as more data becomes available. The EarthScope program is dedicated to determining the three dimensional structure of the North American continent. Future uses of the data that it produces might include
hydrocarbon exploration
Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for deposits of hydrocarbons, particularly petroleum and natural gas, in the Earth using petroleum geology.
Exploration methods
Vis ...
,
aquifer
An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...
boundary establishment,
remote sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth ...
technique development, and earthquake risk assessment. Due to the open and free-to-the-public data portals that EarthScope and its partners maintain, the applications are limited only by the creativity of those who wish to sort through the gigabytes of data. Also, because of its scale, the program will undoubtedly be the topic of casual conversation for many people outside of the geologic community. EarthScope chatter will be made by people in political, educational, social, and scientific arenas.
Geologic Legacy
The multidisciplinary character of EarthScope will create stronger network connections between geologists of all types and from around the country. Building an Earth model of this scale requires a complex community effort, and this model is likely to be the first EarthScope legacy. Researchers analyzing the data will leave us with a greater scientific understanding of
geologic resources in the
Great Basin
The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...
and of the evolution of the
plate boundary
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large te ...
on the North American west coast. Another geologic legacy desired by the initiative, is to invigorate the Earth sciences community. Invigoration is self-perpetuating as evidenced by participation from thousands of organizations from around the world and from all levels of students and researchers. This leads to a significantly heightened awareness within the general public, including the next cohort of prospective Earth scientists. With further evolution of the EarthScope project, there may even be opportunities to create new observatories with greater capabilities, including extending the USArray over the
Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
and the
Gulf of California
The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...
. There is much promise for EarthScope tools and observatories, even after retirement, to be used by universities and professional
geologists
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althoug ...
. These tools include the physical equipment, software invented to analyze the data, and other data and educational products initiated or inspired by EarthScope.
Political Legacy
The science produced by EarthScope and the researchers using its data products will guide lawmakers in environmental policy, hazard identification, and ultimately, federal funding of more large-scale projects like this one. Besides the three physical dimensions of North America's structure, a fourth dimension of the continent is being described through
geochronology
Geochronology is the science of determining the age of rocks, fossils, and sediments using signatures inherent in the rocks themselves. Absolute geochronology can be accomplished through radioactive isotopes, whereas relative geochronology is pr ...
using EarthScope data. Improving understanding of the continent's geologic history will allow future generations to more efficiently manage and utilize geologic resources and live with
geologic hazards
A geologic hazard or geohazard is an adverse geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological process ...
.
Environmental policy
Environmental policy is the commitment of an organization or government to the laws, regulations, and other policy mechanisms concerning environmental issues. These issues generally include air and water pollution, waste management, ecosystem mana ...
laws have been the subject of some controversy since the European settlement of North America. Specifically, water and
mineral rights
Mineral rights are property rights to exploit an area for the minerals it harbors. Mineral rights can be separate from property ownership (see Split estate). Mineral rights can refer to sedentary minerals that do not move below the Earth's surfac ...
issues have been the focus of dispute. Representatives in Washington D.C. and the state capitals require guidance from authoritative science in drafting the soundest environmental laws for our country. The EarthScope research community is in a position to provide the most reliable course for government to take concerning environmental policy.
Hazard identification with EarthScope is an application already in use. In fact, the
Federal Emergency Management Agency
The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Exec ...
(FEMA) has awarded the
Arizona Geological Survey and its partner universities funding to adopt and maintain eight Transportable Array stations. The stations will be used to update Arizona's earthquake risk assessment.
Social Legacy
For EarthScope to live up to its potential in the
Earth sciences
Earth science or geoscience includes all fields of natural science related to the planet Earth. This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four sphere ...
, the connections between the research and the education and outreach communities must continue to be cultivated. Enhanced public outreach to museums, the
National Park System
The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational properties ...
, and public schools will ensure that these forward-thinking connections are fostered. National media collaboration with high-profile outlets such as
Discovery Channel
Discovery Channel (known as The Discovery Channel from 1985 to 1995, and often referred to as simply Discovery) is an American cable channel owned by Warner Bros. Discovery, a publicly traded company run by CEO David Zaslav. , Discovery Channe ...
,
Science Channel
Science Channel (often simply branded as Science; abbreviated to SCI) is an American pay television channel owned by Warner Bros. Discovery. The channel features programming focusing on science related to wilderness survival, engineering, manu ...
, and
National Geographic
''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
may secure a lasting legacy within the social consciousness of the world. Earth science has already been promoted as a vital modern discipline, especially in today's “green” culture, to which EarthScope is contributing. The size of the EarthScope project augments the growing public awareness of the broad structure of the planet on which we live.
See also
*
German Continental Deep Drilling Programme
The German Continental Deep Drilling Programme (german: Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland, lit=Continental deep-drilling program of the Federal Republic of Germany, abbreviated as the KTB borehole, was a scientific dri ...
(KTB)
*
Kola Superdeep Borehole
The Kola Superdeep Borehole (russian: Кольская сверхглубокая скважина, translit=Kol'skaya sverkhglubokaya skvazhina) SG-3
is the result of a scientific drilling project of the Soviet Union in the Pechengsky District ...
*
San Andreas Fault Observatory at Depth
The San Andreas Fault Observatory at Depth (SAFOD) is a research project that began in 2002 aimed at collecting geological data about the San Andreas Fault for the purpose of predicting and analyzing future earthquakes. The site consists of a p ...
(SAFOD project)
References
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External links
* {{Official website, http://www.earthscope.org/
Incorporated Research Institutions for Seismology (IRIS)University NAVSTAR Consortium (UNAVCO)National Science Foundation (NSF)United States Geological Survey (USGS)
Seismological observatories, organisations and projects
Geodesy
Regional geology
Global Positioning System