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

The 23 November 1980 southern Italy earthquake

1983 ◽  
Vol 73 (1) ◽  
pp. 187-200
Author(s):  
Edoardo Del Pezzo ◽  
Giovanni Iannaccone ◽  
Marcello Martini ◽  
Roberto Scarpa
Keyword(s):  
Main Shock ◽  
Southern Italy ◽  
Epicentral Distance ◽  
Tensile Axis ◽  
Multiple Sequence ◽  
Short Period ◽  
Plane Solution ◽  
Hyperbolic Law ◽  
Aftershock Region ◽  
Good Agreement

abstract The seismic activity associated with the catastrophic southern Italy earthquake was monitored by 11 seismic stations operating before this event, within an epicentral distance of 200 km, and by 32 additional short-period seismometers installed soon after the main shock. The hypocenter of this event was located at 40°46′N and 15°18′E, at 16 km depth. The fault-plane solution reveals normal faulting, with tensile axis dipping 18° and oriented orthogonal to the axis of the Apennines chain. This mechanism is in good agreement with the stress pattern inferred from some previous earthquakes and the local seismotectonics. The hypocenter locations of more than 600 aftershocks, with local magnitudes greater than 2.4, show a pronounced alignment extending for about 70 km, oriented north 120° and scattered laterally less than 15 km. These events are mostly concentrated between 8 and 16 km depth. A cluster of aftershocks occurred close to the hypocenter of the main shock covering a region elongated 25 km which corresponds also to the highly damaged area. No significant spreading of the aftershock area with time is observed, but one of the events with higher magnitude (ML = 4.8, 14 February 1981) is displaced 20 km NW from the tip of the aftershock region. The time evolution of the number of aftershocks fits well Omori's hyperbolic law with a decay coeffcient of 1.07 ± 0.06. The possibility of a future delayed multiple sequence of large events, as already observed in the past along the central and southern Apennines, is discussed. In particular, a relatively high seismic potential seems to exist along the northern boundary of the 1980 rupture segment.

Seismic coda Q and scaling law of the source spectra at the Aeolian Islands, southern Italy

1983 ◽  
Vol 73 (1) ◽  
pp. 97-108
Author(s):  
E. Del Pezzo ◽  
F. Ferulano ◽  
A. Giarrusso ◽  
M. Martini
Keyword(s):  
Southern Italy ◽  
Scaling Law ◽  
Coda Wave ◽  
Corner Frequency ◽  
Volcanic Complex ◽  
Coda Q ◽  
Aeolian Islands ◽  
Scaling Properties ◽  
Linear Pattern ◽  
Seismic Coda

abstract The model developed by Aki and Chouet for the coda wave generation and propagation has been used to calculate the quality factor Q for the zone of the Aeolian Islands, southern Italy, in the frequency range of 1 to 12 Hz, and the scaling properties of the seismic spectrum in the magnitude range of 0.4 to 4.7. The Q found for the Aeolian area has a frequency dependence of the form Q = qfv. The absolute values of Q seem to be dependent on the station and location of the seismic events, confirming the strong lateral heterogeneities in the geological structure beneath the Aeolian Arc. A temporal variation has been noted in the Q calculated at Vulcano station (VPL) in a period of 3 weeks soon after the occurrence of a main shock of ML = 5.5 located near the station. The scaling behavior of this sequence is similar to that obtained in two areas of California and one portion of Japan, with a corner frequency that remains constant with an increasing seismic moment between magnitudes 1 and 4. It differs substantially from the scaling properties of the Hawaian earthquakes that show a linear pattern, without an increase of the stress drop with magnitude. The fact that Vulcano is an active volcano seems not to influence the scaling properties of the seismic sequence localized very near it. It probably indicates that the aftershocks used for calculating the scaling law are generated out of the volcanic complex Lipari-Vulcano, in a zone with a good capability of accumulating the stress.

scholarly journals Design Earthquake Response Spectrum Affected by Shallow Soil Deposit

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Dong-Kwan Kim ◽  
Hong-Gun Park ◽  
Chang-Guk Sun
Keyword(s):  
Soil Depth ◽  
Site Response ◽  
Response Spectrum ◽  
Soft Soil ◽  
Response Spectra ◽  
Earthquake Response ◽  
Ground Acceleration ◽  
Site Class ◽  
Shallow Soil ◽  
Short Period

Site response analyses were performed to investigate the earthquake response of structures with shallow soil depth conditions in Korea. The analysis parameters included the properties of soft soil deposits at 487 sites, input earthquake accelerations, and peak ground-acceleration levels. The response spectra resulting from numerical analyses were compared with the design response spectra (DRS) specified in the 2015 International Building Code. The results showed that the earthquake motion of shallow soft soil was significantly different from that of deep soft soil, which was the basis of the IBC DRS. The responses of the structures were amplified when their dynamic periods were close to those of the site. In the case of sites with dynamic periods less than 0.4 s, the spectral accelerations of short-period structures were greater than those of the DRS corresponding to the site class specified in IBC 2015. On the basis of these results, a new form of DRS and soil factors are proposed.

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.

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.

Estimates of short-period Q values and seismic moments from coda waves for earthquakes of the Beijing and Yun-nan regions of China

1984 ◽  
Vol 74 (4) ◽  
pp. 1189-1207
Author(s):  
Peishan Chen ◽  
Otto W. Nuttli ◽  
Wenhua Ye ◽  
Jiazheng Qin
Keyword(s):  
Wave Theory ◽  
Seismic Intensity ◽  
Body Waves ◽  
Wave Frequency ◽  
Coda Waves ◽  
Coda Wave ◽  
Master Curves ◽  
Beijing Area ◽  
Short Period ◽  
Simple Equations

Abstract Coda waves are used to determine the Q value of short-period waves in the Beijing area and in Yun-nan Province, China, and the seismic moments of the earthquakes studied. For the Beijing area the Q0, or 1-Hz value, is found to be approximately 400, with little or no indication of frequency dependence of Q for frequencies near 1 Hz in that region. For Yun-nan Province, the Q0 value is about 180, and the data suggest that Q(f) = Q0f0.2, where f is wave frequency. These values are in fairly good agreement with short-period Q estimates made for those regions by Chen and Nuttli (1984), on the basis of attenuation of seismic intensity values. Hermann's (1980) application of Aki's (1969) coda wave theory is extended, to provide simple equations for calculating master curves for coda wave studies. Two types of master curves provide independent estimates of Q0 and of the dependency of Q on wave frequency. For the data analyzed the two methods gave similar results. A third type of master curves gives estimates of the seismic moments of the earthquakes studied. The moments obtained by this means agree with values obtained by the conventional methods of analysis that use the spectrum of body waves or surface waves.

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.

Sign in / Sign up

Export Citation Format

Share Document