Analysis of artifacts and systematic errors of the Iranian Seismological Center’s earthquake catalog

Naserieh, Saeid; Karkooti, Ehsan; Dezvareh, Mohsen; Rahmati, Mehdi

doi:10.1007/s10950-019-09828-z

Cited by 13 publications

(3 citation statements)

References 53 publications

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“…Obvious differences are observed from focal depth, especially for the shallow crustal earthquakes. In general, the focal depth of the event is a location parameter often poorly constrained, and thus significant differences can be observed among different authoritative sources (Naserieh et al 2019).…”

Section: Structure Of the Databankmentioning

confidence: 99%

The recently compiled strong motion databank of Iran

Shokouhirad,

Ansari,

Ghafory-Ashtiany

2023

Preprint

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This paper presents a comprehensive and integrated databank of the Iranian strong ground motions that occurred from 1973 to 2018. The databank consists of 7196 three-component acceleration records from 3180 earthquakes and 1157 stations in Iran. In this paper, the characteristics of the Iranian strong ground motion data are presented in terms of event, station, and recording distributions. The events are characterized by magnitude in the range 2.4–7.7. Shear wave velocity has been measured and reported at 603 strong motion stations of the databank. In this study, three different empirical techniques are applied to classify the stations. A new method is proposed for site classification based on the correlation coefficient between the horizontal-to-vertical (H/V) response spectral ratios of the ground motion records recorded by each station. It is noticeable that the raw accelerograms have been uniformly processed in the entire databank using the filtering and wavelet de-noising methods to remove high- and low-frequency noise. Moreover, by comparison between the Fourier Amplitude Spectrum (FAS) of the noises detected in all acceleration and velocity time series by the filtering and the wavelet de-noising methods, it was determined that the mean and mode of FAS of the noises detected by the wavelet de-noising method in most of the frequencies is higher than mean and mode of FAS of the noises detected by the filtering method.

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Section: Structure Of the Databankmentioning

confidence: 99%

The recently compiled strong motion databank of Iran

Shokouhirad,

Ansari,

Ghafory-Ashtiany

2023

Preprint

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“…This network has the official responsibility of determining the location and magnitude of the earthquakes in Iran in a timely manner. This network consists of 71 broad-band stations equipped with Trillium-40 s, Trillium-120s, CMG3ESP-120s and CMG3T-360s, 49 stations equipped with SS1 short-period and one long-period boreholes station (Naserieh et al 2019). Depending on the type of the stations, waveforms have been digitized with a sampling rate of 50 or 100 samples per second.…”

Section: Waveform Datamentioning

confidence: 99%

“…At 90 per cent significant level, the null hypothesis is not rejected.Station corrections term correlates with site conditions. All the stations used in this study are sited on hard rock (bedrock)(Naserieh et al 2019). Variability in site response and local changing attenuation among the rock sites and the lateral variations of attenuation in each site (local conditions) are evaluated based on the analysis of regression residuals for vertical component on a station-by-station basis.…”

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confidence: 99%

Local and regional P-wave spectral attenuation model for Iran

Bajestani

Ansari

Karkooti

2020

Geophysical Journal International

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Summary A robust frequency-dependent local and regional P wave attenuation model is estimated for continental paths in the Iranian Plateau. In order to calculate the average attenuation parameters, 46337 vertical-component waveforms related to 9267 earthquakes, which are recorded at the Iranian Seismological Center (IRSC) stations, have been selected in the distance range 10 to 1000 km. The majority of the event's magnitudes are less than 4.5. This collection of records provides high spatial ray path coverage. Results indicate that the shape of attenuation P wave curve versus distance is not uniform and has three distinct sections with hinges at 90 and 175 km. A tri-linear model for attenuation of P wave amplitude in the frequency range 1–10 Hz is proposed in this study. Fourier spectral amplitudes are found to decay as R−1.2 (where R is hypocentral distance), corresponding to geometric spreading within 90 km from the source. There is a section from 90 to 175 km, where the attenuation is described as R0.8, and the attenuation is described well beyond 175 km by R−1.3. Moreover, the average quality factor for Pg and Pn waves (QPg and QPn), related to anelastic attenuation is obtained as Qpg = (54.2 ± 2.6)f(1.0096±0.07) and Qpn = (306.8 ± 7.4)f (0.51±0.05). There is a good agreement between the results of the model and observations. Also, the attenuation model shows compatibility with the recent regional studies. From the results it turns out that the amplitude of P waves attenuates more rapidly in comparison with the global models in local distances.

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