USGS announces awards for 2018 earthquake monitoring and research
The U.S Geological Survey announces that the agency has awarded more than $20 million in 2018 for earthquake monitoring and applied research.Read Story
Better Performance and New Features on Earthquake Website
Better performance and new features: landslides and liquefaction estimates, population map layer, Spanish Did You Feel It?, and aftershock forecasts.Read More
Seismic Sensors Record a Hurricane’s Roar
Newly installed infrasound sensors at a Global Seismographic Network station on Puerto Rico recorded the sounds of Hurricane Maria passing overhead.Read Story
Mission Areas L2 Landing Page Tabs
Evidence of volcanic and glacial activity in Chryse and Acidalia Planitiae, Mars
Chryse and Acidalia Planitiae show numerous examples of enigmatic landforms previously interpreted to have been influenced by a water/ice-rich geologic history. These landforms include giant polygons bounded by kilometer-scale arcuate troughs, bright pitted mounds, and mesa-like features. To investigate the significance of the last we have...Martinez-Alonso, Sara; Mellon, Michael T.; Banks, Maria E.; Keszthelyi, Laszlo P.; McEwen, Alfred S.
Frictional strengths of talc-serpentine and talc-quartz mixtures
Talc is a constituent of faults in a variety of settings, and it may be an effective weakening agent depending on its abundance and distribution within a fault. We conducted frictional strength experiments under hydrothermal conditions to determine the effect of talc on the strengths of synthetic gouges of lizardite and antigorite serpentinites...Moore, Diane E.; Lockner, D.A.
Geodetic slip model of the 2011 M9.0 Tohoku earthquake
The three-dimensional crustal displacement field as sampled by GPS is used to determine the coseismic slip of the 2011 M9.0 Tohoku Earthquake. We employ a spherically layered Earth structure and use a combination of onland GPS, out to ∼4000 km from the rupture, and offshore GPS, which samples the high-slip region on the interplate boundary along...Pollitz, Fred; Burgmann, Roland; Banerjee, Paramesh
Geoinformatics in the public service: building a cyberinfrastructure across the geological surveys
Advanced information technology infrastructure is increasingly being employed in the Earth sciences to provide researchers with efficient access to massive central databases and to integrate diversely formatted information from a variety of sources. These geoinformatics initiatives enable manipulation, modeling and visualization of data in a...Keller, G. Randy; Baru, Chaitanya; Allison, M. Lee; Gundersen, Linda C.; Richard, Stephen M.
Geomagnetic referencing in the arctic environment
Geomagnetic referencing is becoming an increasingly attractive alternative to north-seeking gyroscopic surveys to achieve the precise wellbore positioning essential for success in today's complex drilling programs. However, the greater magnitude of variations in the geomagnetic environment at higher latitudes makes the application of geomagnetic...Poedjono, B.; Beck, N.; Buchanan, A. C.; Brink, J.; Longo, J.; Finn, C.A.; Worthington, E.W.
Ground motion attenuation during M 7.1 Darfield and M 6.2 Christchurch, New Zealand, earthquakes and performance of global Ppedictive models
The M 7.1 Darfield earthquake occurred 40 km west of Christchurch (New Zealand) on 4 September 2010. Six months after, the city was struck again with an M 6.2 event on 22 February local time (21 February UTC). These events resulted in significant damage to infrastructure in the city and its suburbs. The purpose of this study is to evaluate the...Segou, Margaret; Kalkan, Erol
Ground-Motion Prediction Equations (GMPEs) from a global dataset: the PEERPEER NGA equations
The PEER NGA ground-motion prediction equation s (GMPEs) were derived by five developer teams over several years, resulting in five sets of GMPEs. The teams used various subsets of a global database of ground motions and metadata from shallow earthquakes in tectonically active regions in the development of the equations. Since their publication,...Akkar, Sinan; Gulkan, Polat; van Eck, Torild; Boore, David M.
High-frequency filtering of strong-motion records
The influence of noise in strong-motion records is most problematic at low and high frequencies where the signal to noise ratio is commonly low compared to that in the mid-spectrum. The impact of low-frequency noise (<1 Hz) on strong-motion intensity parameters such as ground velocities, displacements and response spectral ordinates can be...Douglas, J.; Boore, D.M.
History of plains resurfacing in the Scandia region of Mars
We present a preliminary photogeologic map of the Scandia region of Mars with the objective of reconstructing its resurfacing history. The Scandia region includes the lower section of the regional lowland slope of Vastitas Borealis extending about 500–1800 km away from Alba Mons into the Scandia sub-basin below −4800 m elevation. Twenty mapped...Tanaka, Kenneth L.; Fortezzo, Corey M.; Hayward, Rosalyn K.; Rodriguez, J. Alexis P.; Skinner, James A.
In situ measurements of post-fire debris flows in southern California: Comparisons of the timing and magnitude of 24 debris-flow events with rainfall and soil moisture conditions
Debris flows often occur in burned steeplands of southern California, sometimes causing property damage and loss of life. In an effort to better understand the hydrologic controls on post-fire debris-flow initiation, timing and magnitude, we measured the flow stage, rainfall, channel bed pore fluid pressure and hillslope soil-moisture accompanying...Kean, J.W.; Staley, D.M.; Cannon, S.H.
Inversion of ground-motion data from a seismometer array for rotation using a modification of Jaeger's method
We develop a new way to invert 2D translational waveforms using Jaeger's (1969) formula to derive rotational ground motions about one axis and estimate the errors in them using techniques from statistical multivariate analysis. This procedure can be used to derive rotational ground motions and strains using arrayed translational data, thus...Chi, Wu-Cheng; Lee, W.H.K.; Aston, J.A.D.; Lin, C.J.; Liu, C.-C.
Landslide inventories: The essential part of seismic landslide hazard analyses
A detailed and accurate landslide inventory is an essential part of seismic landslide hazard analysis. An ideal inventory would cover the entire area affected by an earthquake and include all of the landslides that are possible to detect down to sizes of 1-5. m in length. The landslides must also be located accurately and mapped as polygons...Harp, E.L.; Keefer, D.K.; Sato, H.P.; Yagi, H.