Imaging Global Seismic Phase Arrivals by Stacking Array Processed Short-Period Data

2006 ◽  
Vol 77 (6) ◽  
pp. 697-707 ◽  
Author(s):  
S. Rost ◽  
M. S. Thorne ◽  
E. J. Garnero
Keyword(s):  
Short Period ◽  
Period Data

scholarly journals Capabilities of Satellite-Based Precipitation to Estimate the Spatiotemporal Variation of Flood/Drought Class in Poyang Lake Basin

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Xianghu Li ◽  
Qi Zhang ◽  
Xuchun Ye
Keyword(s):  
Poyang Lake ◽  
Rainfall Data ◽  
Data Series ◽  
Lake Basin ◽  
Long Period ◽  
Poyang Lake Basin ◽  
Short Period ◽  
Period Data ◽  
Temporal And Spatial ◽  
Drought Classes

Poyang Lake basin is one of the most frequently affected areas by a variety of flood or drought events in China. Satellite-based precipitation data have greatly improved their temporal and spatial resolution in recent years, but the short length of records limited their applications in some fields. This paper compared and evaluated the creditability of using a short period data series to estimate the statistics characteristics of long period data series and investigated the usefulness of TRMM rainfall data for monitoring the temporal and spatial distribution of flood/drought classes by theZindex method in Poyang Lake basin. The results show that (1) the 1998–2010 data series are sufficiently robust to depict the statistics characteristics of long period data; (2) the intra-annual distribution and interannual variability of flood/drought classes based on TRMM rainfall data matched well with the results from rain gauges data; (3) the spatial agreement between TRMM and interpolated gauges rainfall varied with the precipitation characteristics; and (4) TRMM rainfall data described the similar spatial pattern of flood/drought classes with the interpolated gauges rainfall. In conclusion, it is suitable and credible for flood/drought classes evaluation based on the TRMM rainfall data in Poyang Lake basin.

Site response using coda-wave techniques: Applications to short period data from central and southern Italy

1991 ◽  
Vol 136 (1) ◽  
pp. 127-141 ◽  
Author(s):  
Edoardo Del Pezzo ◽  
Marcello Martini ◽  
Giuliano Milana
Keyword(s):  
Southern Italy ◽  
Site Response ◽  
Coda Wave ◽  
Short Period ◽  
Period Data

Noise level variation at norsar and its effect on detectability

1977 ◽  
Vol 67 (2) ◽  
pp. 479-492 ◽  
Author(s):  
F. Ringdal ◽  
H. Bungum
Keyword(s):  
Atmospheric Pressure ◽  
Noise Level ◽  
Amplitude Distribution ◽  
P Wave ◽  
Seasonal Fluctuations ◽  
Long Period ◽  
Short Period ◽  
Noise Data ◽  
Band Pass ◽  
Period Data

Abstract For a 3-year period, noise level measurements of short- and long-period data at NORSAR have been sampled at hourly intervals. Significant seasonal fluctuations in noise level have been found, in particular for long-period data. The noise amplitude distribution is approximately lognormal for band-pass filtered short-period data in the P-wave detection band, while the long-period noise data show a skewness that cannot be represented by a lognormal distribution. Diurnal fluctuations in noise level are quite small, but definitely present both for short and horizontal component long-period data. Cultural sources are found to account for the short-period variability, while the long-period fluctuations are attributed to atmospheric pressure variation. Event detection performance generally follows the noise level trends, with an increase in the number of reported events during summer of about 50 per cent relative to winter.

A real-time digital seismic event detection and recording system for network applications

1982 ◽  
Vol 72 (6A) ◽  
pp. 2339-2348
Author(s):  
Andrew J. Michael ◽  
Stephen P. Gildea ◽  
Jay J. Pulli
Keyword(s):  
Real Time ◽  
Event Detection ◽  
Seismic Event ◽  
Weather Conditions ◽  
Recording System ◽  
Walsh Transform ◽  
Long Period ◽  
Short Period ◽  
Seismic Event Detection ◽  
Period Data

abstract A real-time digital seismic event detection and recording system has been developed for the MIT Seismic Network. The system has been designed specifically for an environment of low natural seismic activity and for surface stations which are often influenced by weather conditions and cultural noise. The system runs on an HP-1000 computer and can handle up to 16 channels of short- and long-period data. The structure of the system centers around the event detectors, one for short-period data and one for long-period data. These detectors base their decisions on a metric computed from the Walsh transform of the data. This allows them to detect changes in the amplitude of the waveform as well as frequency shifts. Detections at several stations are correlated to prevent glitches from triggering the detector. Present operation successfully saves those events that are large enough for analysis and leaves 23 of the computer available for general timesharing use.

Definition and identification of seismic events in the USSR in 1971

1974 ◽  
Vol 64 (3-1) ◽  
pp. 607-636
Author(s):  
Ola Dahlman ◽  
Hans Israelson ◽  
Atle Austegard ◽  
Gunnel Hörnström
Keyword(s):  
Focal Depth ◽  
Seismic Monitoring ◽  
Seismic Events ◽  
Long Period ◽  
The Earth ◽  
Short Period ◽  
Complete Test ◽  
Period Data ◽  
Test Ban ◽  
Test Ban Treaty

abstract Seismic events reported to have occurred in the USSR in 1971 are studied to assess the seismic monitoring problem as it may occur in the context of a complete test-ban treaty. Available epicenter data of a total of 199 events, 180 earthquakes and 19 explosions, are presented. Focal depth estimates reported by the National Oceanic and Atmospheric Administration, U.S., and the Institute of Physics of the Earth, Moscow, are compared. Identification parameters determined using short- and long-period data from Hagfors Observatory and supplementary short-period data from the Yellowknife array station in Canada are presented. To study the combined operative efficiency and applicability of available identification parameters, the reported depth estimates and the identification data are assessed in a defined way.

Seismic event identification by negative evidence

1974 ◽  
Vol 64 (6) ◽  
pp. 1671-1683
Author(s):  
Eva Elvers
Keyword(s):  
Signal Amplitude ◽  
False Alarms ◽  
Negative Evidence ◽  
Event Identification ◽  
Underground Nuclear Explosions ◽  
Nuclear Explosions ◽  
Short Period ◽  
Seismic Discrimination ◽  
Period Detection ◽  
Period Data

abstract A decision-theoretical model for seismic discrimination between earthquakes and underground nuclear explosions is developed. The influence of long- and short-period detection thresholds on the probabilities to identify explosions and to make false alarms is discussed. The model includes identification by negative evidence. This kind of identification is considered in the case when only short-period data are available and when the long-period signal amplitude is supposed to be less than or equal to the seismic noise amplitude. For one set of data—obtained from North American events at the Hagfors Observatory in Sweden—the applicability of the m(M)-method is increased about half a magnitude by including identification by negative evidence.

A Procedure for the Extraction of Multiple Body Wave Traveltimes From Seismological Waveform Data

1991 ◽  
Vol 02 (01) ◽  
pp. 276-283 ◽  
Author(s):  
GÖTZ H.R. BOKELMANN ◽  
PAUL G. SILVER
Keyword(s):  
Travel Time ◽  
Seismic Velocity ◽  
Body Wave ◽  
Path Model ◽  
Nonlinear Dependence ◽  
Model Parameters ◽  
Time Inversion ◽  
Waveform Data ◽  
Short Period ◽  
Period Data

A scheme for extracting multiple phase body wave traveltimes is presented which is most applicable to teleseismic broadband and short period data from permanent and portable instruments. The method specifically allows for the nonlinear dependence of waveforms on travel time by performing a nonlinear search over a reduced set of “projected model parameters”. This reduced set is found by splitting the method into two parts, the nonlinear dependence of waveforms on traveltime perturbations (particularly strong for broadband and short period data) and the linearizable dependence of travel time perturbations on variations in seismic velocity. By use of generalized inverse, the traveltime perturbations can be adequately characterized by a reduced number of linear combinations of model parameters. Consequently, the nonlinear search is performed over an optimally compact model space. The technique can consider simultaneously a large number of body wave phases creating a systematic methodology for extracting large numbers of traveltimes from single source-receiver pairs. The resulting path model may or may not be of physical significance; the primary goal is the extraction of travel times that may be subsequently used for a more comprehensive travel time inversion.

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