INVESTIGATIONS OF SEISMIC-WAVE ARRIVAL TIME BIASES IN THE STATIONS OF TEHRAN SEISMIC NETWORK

Q: How can I download an article?

To download an article from SID, first log in to the site, search for the article title, and click on the 'Download Article' option.

Q: How can I download an ISI article?

To download an ISI article on SID, enter the keyword or article title in the search bar, view the relevant results, click on the desired article, and select the 'Download Article' option.

Q: How can I access the SID database?

To access the SID database, visit SID.ir, create an account, and log in to access scientific resources.

Q: Is downloading articles from SID free?

Some articles on SID are available for free, while others require payment. Details are specified on the article's page.

REZAPOUR MAHDI; MOTAGHI ALI ASGHAR

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

Journal Paper

Paper Information

Journal: Journal of the Earth and Space Physics Year:2008 | Volume:34 | Issue:1 Page(s): 125-134

Download Full-Text

Persian Verion

View:

840

Download:

Cites:

Information Journal Paper

Title

INVESTIGATIONS OF SEISMIC-WAVE ARRIVAL TIME BIASES IN THE STATIONS OF TEHRAN SEISMIC NETWORK

Author(s)

REZAPOUR MAHDI | MOTAGHI ALI ASGHAR | Issue Writer Certificate

Keywords

TEHRAN SEISMIC NETWORKQ3

ARRIVAL TIME RESIDUALQ3

BACK AZIMUTHQ3

SYSTEMATIC ERRORQ3

Abstract

The travel time observations contain information about the location and time of origin of the seismic source and the velocity structure in the region between the source and receivers. So, the travel-time residuals as criteria are used in the seismic topographical studies and locating seismic events, etc. There are many possible factors that create systematic bias in travel-time residuals. Some of the important systematic factors which might lead to such bias include: azimuth variation due to geological structure; SYSTEMATIC ERRORs in recording system or instrumental error; phase picking error; location error and etc.Systematically biases and instrumental errors in seismic stations are very difficult to address in many earthquake location methods. Minimizing the effects of these errors is very important to improve earthquake locations. In order to identify and minimize them, we analyze the time residuals of the first P-wave arrivals at 9 stations of the Tehran network using the data base from 1996 through 2005.The azimuth variation can be due to a combination of earth structure near the source and receiver. In order to identify earth structure near the stations we used the data of events which occurred within 100 kilometers of each station. Also, to discriminate different source regions we divided the Earth's surface into 5° in azimuth by 100 km in distance relative to the station.In this analysis time residual versus BACK AZIMUTH data of stations from events located within 100 kilometers are sorted, then averaged over 5° BACK AZIMUTHal intervals. In each bin, we have an average residual and an azimuth centered on the bin. Then, for the average residual versus the corresponding BACK AZIMUTH, a least square curve was fitted due to dependent equation of the form (Dziewonski and Anderson, 1983): dt=A°+A1 Cos (q-A2)+A3Cos2 (q-A4) Where q is the azimuth from the station (back azimuth) to the event and dt is the average P-wave travel time residual into the bin 5°×100 km. A0, A1, A2, A3 and A4 are constants.The value of A0 can be jointly related to instrumental error, phase picking error, location error and etc. Since separation of these biases is difficult, and A0 value indicates the total shift of data, we consider A0 as instrumental error or station offset. Therefore, the constant term in azimuth dependent equation is attributed to the average SYSTEMATIC ERRORs at the stations. The value of A0 can indicate an operational quality of a station. By using this procedure we can identify "pathological" stations. As a result, DMW, RAZ and FIR stations show significant azimuthal biases and FIR and AFJ stations have had considerable SYSTEMATIC ERRORs. QOM, VRN and MHD stations have had reliable records according to the stability of the azimuthally dependent curve. Also, all of the stations are graded in 4 azimuth windows according to their functional quality.

Cites

No record.

References

No record.

Cite

APA: Copy

REZAPOUR, MAHDI, & MOTAGHI, ALI ASGHAR. (2008). INVESTIGATIONS OF SEISMIC-WAVE ARRIVAL TIME BIASES IN THE STATIONS OF TEHRAN SEISMIC NETWORK. JOURNAL OF THE EARTH AND SPACE PHYSICS, 34(1), 125-134. SID. https://sid.ir/paper/80357/en

Vancouver: Copy

REZAPOUR MAHDI, MOTAGHI ALI ASGHAR. INVESTIGATIONS OF SEISMIC-WAVE ARRIVAL TIME BIASES IN THE STATIONS OF TEHRAN SEISMIC NETWORK. JOURNAL OF THE EARTH AND SPACE PHYSICS[Internet]. 2008;34(1):125-134. Available from: https://sid.ir/paper/80357/en

IEEE: Copy

MAHDI REZAPOUR, and ALI ASGHAR MOTAGHI, “INVESTIGATIONS OF SEISMIC-WAVE ARRIVAL TIME BIASES IN THE STATIONS OF TEHRAN SEISMIC NETWORK,” JOURNAL OF THE EARTH AND SPACE PHYSICS, vol. 34, no. 1, pp. 125–134, 2008, [Online]. Available: https://sid.ir/paper/80357/en

Related Journal Papers