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Earthquake prediction assessment using VLF radio signal sounding and space-based ULF emission observation

Mahmoudian Alireza, Safari Mohsen, Rezapour Mehdi

Acta Geophysica

2022

Vol. 70, no 3

1269--1284

The present paper aims at earthquake prediction assessment in Iran using VLF radio signal sounding and space-based ULF emission observation. VLF subionospheric data using the Denizkoy transmitter in Turkey at 26.7 kHz and a receiving station in Tehran are incorporated. Three earthquake events during 2019 located at different distances to the signal propagation path are used in this study. The short-term variations in the VLF signal for the 5 days averaged amplitude, as well as the deviation of the VLF signal against the 30 days averaged signal to monitor the alternation in the trend, are employed in this study to perform earthquake prediction assessment using VLF radio signal sounding. Several characteristic parameters of the VLF signal such fall-time, minimum 1 and minimum 2 throughout the day are used. A threshold over the standard deviation of the signal is used to determine the signal anomaly. The signal anomalies associated with three selected events and the correlation of prediction with the distance are discussed. A decision-making procedure for the detection of EQ-related anomalies based on the assessment of the proposed approach is introduced. The ULF emissions recorded by the China Seismo-Electromagnetic Satellite (CSES) are provided and associated with the two analyzed earthquakes using the VLF data due to lack of time coverage for the third case. The space-based detected ULF signals are presented and discussed. The proximity of the detected ULF emission with respect to the earthquake epicenter is discussed.

Haulage system selection for Parvadeh Coal Mine using multi-criteria decision making methods

Ghasvareh Mohammad Amin, Safari Mohsen, Nikkhah Majid

Mining Science

2019

Vol. 26

69--90

One of the key components of any project, especially mining projects, is the selection and design of haulage equipment. In most mining activities, which sometimes include mining machinery, haulage costs form a major part of the operating expenses as a matter of concern to mine managers. Due to various factors affecting the selection process of a haulage system, it is not considered a crystal clear one. Because of the complexity and multi-criterion characteristic of the selection process, the use of multi-criterion decision-making methods can be of great help to solve this problem. The TOPSIS, AHP and VIKOR methods among the multi-criterion decision-making methods are some options which are based on priority ranking. In the current paper, the loading systems of conveyors, wagons and winches as well as the locomotives and wagons are investigated. Then, the aforementioned systems are used to make a hybrid based on eight criteria, which yields the best loading system for the Parvadeh Coal Mine in Tabas. Since the obtained results were not consistent with each other in some cases, some integration techniques were utilized to employ the above methods. After integrating the results of the ranking methods, the conveyor haulage system was eventually introduced as the best option.