Earthquake source parameters in Norway determined with empirical Green’s functions

Demuth, Andrea; Tjåland, Norunn; Ottemöller, Lars

doi:10.1007/s10950-019-09831-4

Cited by 6 publications

(4 citation statements)

References 36 publications

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“…The source rise time and source duration (τ, τ1/2) for the main events were computed from the STFs each time it had a pulse-like shape. The corner frequency (fc) was determined from the source duration using equation ( 8) from [20] and finally we computed the source radius using formula (2).…”

Section: Methods and Datamentioning

confidence: 99%

“…This gives indications about the amount of released energy and also may estimate the destructive potential of an earthquake. A major disadvantage is given by the estimation of accuracy since its uncertainties are rather high, due to the corner frequency determinations that could increase or decrease the stress drop value by at least three times [20].…”

Section: Introductionmentioning

confidence: 99%

“…Another notable feature highlighted by previous research [26][27][28] reveals similar properties for small and large earthquakes, changing only in scale, which would imply a constant stress drop for the whole range of magnitudes. However, several studies have shown [20,29] that for small earthquakes (M < 3) there is an increasing trend towards stress drop at the seismic moment. One of the features that could cause this behavior is the strong attenuation effect within the upper crust, which acts as a filter, removing the high frequencies (f > 10 Hz) and limiting the corner frequencies' resolution [30], especially for small earthquakes, leading to an underestimation of the stress drop.…”

Section: Introductionmentioning

confidence: 99%

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Earthquake Source Properties of a Lower Crust Sequence and Associated Seismicity Perturbation in the SE Carpathians, Romania, Collisional Setting

et al. 2021

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Romanian seismicity is mainly confined to the Eastern Carpathians Arc bend (ECAB), where strong subcrustal earthquakes (magnitude up to 7.9) are generated in a narrow lithospheric body descending into the mantle. The seismic activity in the overlying crust is spread over a larger area, located mostly toward the outer side of the ECAB. It is significantly smaller than subcrustal seismicity, raising controversies about possible upper mantle-crust coupling. A significant earthquake sequence took place in the foreland of the ECAB triggered on 22 November 2014 by a mainshock of magnitude 5.7 (the greatest instrumentally recorded earthquake in this region) located in the lower crust. The mainshock triggered a significant increase in the number of small-magnitude events spread over an unusually large area in the ECAB. The paper’s goal is to compute the source parameters of the earthquakes that occurred during the aforementioned sequence, by empirical application of Green’s function and spectral ratio techniques. Fault plane solutions are determined using multiple methods and seismicity evolution at regional scale is investigated. Our results highlight a still active deformation regime at the edge of the EE Craton, while the source parameters reveal a complex fracture of the mainshock and a very high-stress drop.

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Section: Methods and Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Earthquake Source Properties of a Lower Crust Sequence and Associated Seismicity Perturbation in the SE Carpathians, Romania, Collisional Setting

et al. 2021

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“…Hal ini agar temuan yang diperoleh baik berupa bentuk grafik relasi empiris 𝑀 w − 𝑀 o maupun persamaan empiris terkait bisa berlaku universal (e.g., Ali and Shieh, 2013). Ketiga grafik relasi empiris 𝑀 w − 𝑀 o (Gambar 2) jelas menunjukkan 𝑀 w sebagai fungsi logaritmik dari 𝑀 o yang konsisten dengan temuan penelitian terdahulu (Hanks and Kanamori, 1979;Kanamori, 1983;Ali and Shieh, 2013;Wu et al, 2013;Bora, 2016;Konstantinou and Melis, 2017;Wang, 2018;Das et al, 2019;Demuth et al, 2019;Ji and Yoshioka, 2021). Ketiga bentuk grafik tersebut jelas menunjukkan 𝑀 w yang mengalami saturasi untuk 𝑀 o yang semakin besar.…”

Section: Grafik 𝑴 𝐰 Terhadap 𝑴 𝐨unclassified

Analisis Relasi Momen Seismik Dan Magnitudo Momen Untuk Variasi Kedalaman Sumber Gempa Tektonik (Shallow, Intermediate, and Deep Sources)

Salsabillah

Prastowo

2022

IFI

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Abstrak Karakteristik gempa dapat dipelajari melalui relasi antara parameter-parameter sumber. Dua parameter sumber yang berfungsi sebagai ukuran kekuatan gempa adalah magnitudo momen dan momen seismik . Penelitian ini fokus pada analisis relasi empiris untuk variasi kedalaman: shallow (0-100 km), intermediate (100-300 km), dan deep ( 300 km) sources. Data penelitian adalah 242 gempa tektonik yang diperoleh dari berbagai sumber reliabel (publikasi internasional) baik intraplate maupun interplate events yang terjadi di seluruh dunia, termasuk Indonesia antara 1905-2016 dengan magnitudo antara 4,45 9,20. Hasil penelitian berupa persamaan empiris untuk setiap kedalaman sumber, = 0,287 ln + 5,952 (shallow sources), = 0,290 ln + 6,047 (intermediate sources) dan = 0,285 ln + 5,816 (deep sources). Ketiga persamaan tersebut bersifat self-consistent karena merepresentasikan relasi empiris dengan bentuk grafik yang sama. Nilai koefisien ln untuk ketiga persamaan tidak berbeda sampai dengan desimal kedua sedangkan variasi kecil nilai konstanta tidak memberikan informasi yang jelas tentang perbedaan antara ketiga sumber gempa. Relasi empiris yang diperoleh dari penelitian ini konsisten dengan temuan penelitian terdahulu, yaitu merupakan fungsi logaritmik . Selain temuan tersebut, penelitian ini juga menemukan distribusi mayor kedalaman sumber adalah kurang dari 20 km (shallow sources), antara 100-200 km (intermediate sources), dan 550-600 km (deep sources). Temuan ini konsisten dengan karakteristik seismisitas global. Hasil-hasil penelitian ini memberikan pemahaman tentang relasi yang bersifat universal (tidak bergantung pada kedalaman sumber gempa) dan global (tidak bergantung pada lokasi kejadian gempa). Kata Kunci: magnitudo momen, momen seismik, relasi empiris , variasi kedalaman sumber Abstract Characteristics of earthquakes can be examined using analysis of source parameters. Two source parameters used as a measure of earthquake strength are momen magnitude and seismic moment . This study focuses on analysis of a empirical relation for varying depths: shallow (0-100 km), intermediate (100-300 km), dan deep ( 300 km). The data were 242 occurrences (intraplate and interplate events worldwide between 1905-2016) obtained from reliable published studies with varying magnitudes of 4.45 9.20. The results were in the form of an empirical equation for each source depth, = 0.287 ln + 5.952 (shallow sources), = 0.290 ln + 6.047 (intermediate sources) dan = 0.285 ln + 5.816 (deep sources). These equations are self-consistent as they represent the relation in the same form of graphs. Coefficients of ln are similar for all the three equations to two decimal places while small variations of constants give no clear information on differences in the source depth. The relation obtained is consistent with previous work in the sense that is a logarithmic function of . In addition, the current study found major earthquakes were distributed at depths below 20 km for shallow sources, between 100-200 km for intermediate sources, 550-600 km for deep sources, in good agreement with characteristics of global seismicity. The results of this study provide a better understanding of the relation, which is universal and global, independent of source depth and location. Keywords: moment magnitude, seismic moment, empirical relation, varying depths

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Source parameters of the Fatehjang, Pakistan earthquake $$({M}_{w} 4.1)$$ of 28 August 2020

Sabahat

Tahir²,

Iqbal³

et al. 2022

Arab J Geosci

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Earthquake source parameters in Norway determined with empirical Green’s functions

Cited by 6 publications

References 36 publications

Earthquake Source Properties of a Lower Crust Sequence and Associated Seismicity Perturbation in the SE Carpathians, Romania, Collisional Setting

Earthquake Source Properties of a Lower Crust Sequence and Associated Seismicity Perturbation in the SE Carpathians, Romania, Collisional Setting

Analisis Relasi Momen Seismik Dan Magnitudo Momen Untuk Variasi Kedalaman Sumber Gempa Tektonik (Shallow, Intermediate, and Deep Sources)

Source parameters of the Fatehjang, Pakistan earthquake $$({M}_{w} 4.1)$$ of 28 August 2020

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