Global Seismographic Network
Programs L2 Landing Page
The Global Seismographic Network (GSN) is a permanent digital network of state-of-the-art seismological and geophysical sensors connected by a telecommunications network. The GSN provides, worldwide monitoring of the Earth, with over 150 modern seismic stations distributed globally.
Zoom in on an area to view all seismic network operation stations on the interactive map.
This interactive map displays seismographic activity. Click on a red seismogram icon or select a region from list list.
Relative azimuth inversion by way of damped maximum correlation estimates
Horizontal seismic data are utilized in a large number of Earth studies. Such work depends on the published orientations of the sensitive axes of seismic sensors relative to true North. These orientations can be estimated using a number of different techniques: SensOrLoc (Sensitivity, Orientation and Location), comparison to synthetics (Ekstrom...Ringler, A.T.; Edwards, J.D.; Hutt, C.R.; Shelly, F.
Temporal variations in Global Seismic Stations ambient noise power levels
Recent concerns about time-dependent response changes in broadband seismometers have motivated the need for methods to monitor sensor health at Global Seismographic Network (GSN) stations. We present two new methods for monitoring temporal changes in data quality and instrument response transfer functions that are independent of Earth seismic...Ringler, A.T.; Gee, L.S.; Hutt, C.R.; McNamara, D.E.
Experimental Investigations Regarding the Use of Sand as an Inhibitor of Air Convection in Deep Seismic Boreholes
INTRODUCTION Tilt has been the nemesis of horizontal long period seismology since its inception. Modern horizontal long period seismometers with their long natural periods are incredibly sensitive to tilt. They can sense tilts smaller than 10 -11 radians. To most readers, this is just a very very small number, so we will begin with an example...Holcomb, L. Gary; Sandoval, Leo; Hutt, Bob
Taking the Earth's pulse
During the past 35 years, scientists have developed a vast network of seismometers that record earthquakes, volcanic eruptions, and nuclear explosions throughout the world. Seismographic data support disaster response, scientific research, and global security. With this network, the United States maintains world leadership in monitoring the...Woodward, Robert L.; Benz, Harly M.; Brown, William M.
Observations and Modeling of Seismic Background Noise
INTRODUCTION The preparation of this report had two purposes. One was to present a catalog of seismic background noise spectra obtained from a worldwide network of seismograph stations. The other purpose was to refine and document models of seismic background noise that have been in use for several years. The second objective was, in...Peterson, Jon R.
An Evaluation of Installation Methods for STS-1 Seismometers
INTRODUCTION This report documents the results of a series of experiments conducted by the authors at the Albuquerque Seismological Laboratory (ASl) during the spring and summer of 1991; the object of these experiments was to obtain and document quantitative performance comparisons of three methods of installing STS-1 seismometers....Holcomb, L. Gary; Hutt, Charles R.
A C Language Implementation of the SRO (Murdock) Detector/Analyzer
A signal detector and analyzer algorithm was described by Murdock and Hutt in 1983. The algorithm emulates the performance of a human interpreter of seismograms. It estimates the signal onset, the direction of onset (positive or negative), the quality of these determinations, the period and amplitude of the signal, and the background noise at the...Murdock, James N.; Halbert, Scott E.
A Numerical Study of Some Potential Sources of Error in Side-by-Side Seismometer Evaluations
INTRODUCTION This report presents the results of a series of computer simulations of potential errors in test data, which might be obtained when conducting side-by-side comparisons of seismometers. These results can be used as guides in estimating potential sources and magnitudes of errors one might expect when analyzing real test data....Holcomb, L. Gary
A Direct Method for Calculating Instrument Noise Levels in Side-by-Side Seismometer Evaluations
INTRODUCTION The subject of determining the inherent system noise levels present in modem broadband closed loop seismic sensors has been an evolving topic ever since closed loop systems became available. Closed loop systems are unique in that the system noise can not be determined via a blocked mass test as in older conventional open loop...Holcomb, L. Gary
IRIS/USGS Plans for Upgrading the Global Seismograph Network
PREFACE This report has been prepared to provide information to organizations that may be asked to participate in a program to upgrade the global seismographic network. In most cases, the organizations that will be offered new instrumentation by the U.S. Geological Survey currently operate stations in the World-Wide Standardized Seismograph...Peterson, Jon; Hutt, Charles R.
Description and Preliminary Testing of the CDSN Seismic Sensor Systems
INTRODUCTION The China Digital Seismograph Network (CDSN) is being designed and installed to provide the People's Republic of China with the facilities needed to create a national digital database for earthquake research. The CDSN, which is being developed jointly by the PRC State Seismological Bureau and the U.S. Geological Survey,...Peterson, Jon; Tilgner, Edwin E.
A New Event Detector Designed for the Seismic Research Observatories
A new short-period event detector has been implemented on the Seismic Research Observatories. For each signal detected, a printed output gives estimates of the time of onset of the signal, direction of the first break, quality of onset, period and maximum amplitude of the signal, and an estimate of the variability of the background noise. On the...Murdock, James N.; Hutt, Charles R.
Although no one can reliably predict earthquakes, today’s technology is advanced enough to rapidly detect seismic waves as an earthquake begins, calculate the maximum expected shaking, and send alerts to surrounding areas before damage can occur. This technology is known as “earthquake early warning” (EEW).
While the number of large earthquakes fell to 12 in 2014, from 19 in 2013, several moderate temblors hit areas relatively new to seismicity, including Oklahoma and Kansas, according to the U.S. Geological Survey. Worldwide, 11 earthquakes reached magnitude 7.0-7.9 and one registered magnitude 8.2, in Iquique, Chile, on April 1.
Scientists from the U.S. Geological Survey and Virginia Tech will install a 20-station seismic network in the central Virginia area beginning Jan. 8. The new sensors – each about the size of a soda can – will provide information to help the researchers study the background seismicity in the area and any continuing aftershocks of the Aug. 23, 2011 earthquake near Louisa and Mineral, Va.