Analysis of the cross-correlation between seismicity and water level in the Aswan area (Egypt) from 1982 to 2010

Telesca, Luciano; ElBary, R. ElShafey Fat; Mohamed, Abbas Ahmed; Gabry, Mohamed El

doi:10.5194/nhess-12-2203-2012

Cited by 18 publications

(5 citation statements)

References 10 publications

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“…Hence it is important to distinguish clustering dynamics from cyclic Poisson processes. Methodologies that are suitable to achieve this are presented in Serinaldi and Kilsby (2013) and Telesca et al (2012).…”

Section: Introductionmentioning

confidence: 99%

Time clustering of wave storms in the Mediterranean Sea

Besio

Briganti

Romano

et al. 2017

Nat. Hazards Earth Syst. Sci.

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Abstract. In this contribution we identify storm time clustering in the Mediterranean Sea through a comprehensive analysis of the Allan factor. This parameter is evaluated from a long time series of wave height provided by oceanographic buoy measurements and hindcast reanalysis of the whole basin, spanning the period 1979-2014 and characterized by a horizontal resolution of about 0.1 • in longitude and latitude and a temporal sampling of 1 h (Mentaschi et al., 2015). The nature of the processes highlighted by the AF and the spatial distribution of the parameter are both investigated. Results reveal that the Allan factor follows different curves at two distinct timescales. The range of timescales between 12 h to 50 days is characterized by a departure from the Poisson distribution. For timescales above 50 days, a cyclic Poisson process is identified. The spatial distribution of the Allan factor reveals that the clustering at smaller timescales is present to the north-west of the Mediterranean, while seasonality is observed across the whole basin. This analysis is believed to be important for assessing the local increased flood and coastal erosion risks due to storm clustering.

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Section: Introductionmentioning

confidence: 99%

Time clustering of wave storms in the Mediterranean Sea

Besio

Briganti

Romano

et al. 2017

Nat. Hazards Earth Syst. Sci.

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“…AF was used to investigate the time dynamics of a variety of natural phenomena [35,36]. If the series of events are Poissonian, meaning that the events are uncorrelated and independent, AF is rather flat for all available timescales, fluctuating at around 1 (except for very large timescales due to finite-size effects [37]); if the series of events are clusterized, the AF changes with the timescale τ, increasing as a power law for a fractal (self-similar) process:…”

Section: The Allan Factormentioning

confidence: 99%

Fractal and Spectral Analysis of Seismicity in the Lai Chau Area (Vietnam)

Telesca,

Thai,

Cao

et al. 2023

Fractal Fract

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The time dynamics of the instrumental seismicity recorded in the area of the Lai Chau reservoir (Vietnam) between 2015 and 2021 were analyzed in this study. The Gutenberg–Richter analysis of the frequency–magnitude distribution has revealed that the seismic catalog is complete for events with magnitudes larger or equal to 0.6. The fractal method of the Allan Factor applied to the series of the occurrence times suggests that the seismic series is characterized by time-clustering behavior with rather large degrees of clustering, as indicated by the value of the fractal exponent α≈0.55. The time-clustering of the time distribution of the earthquakes is also confirmed by a global coefficient of variation value of 1.9 for the interevent times. The application of the correlogram-based periodogram, which is a robust method used to estimate the power spectrum of short series, has revealed three main cycles with a significance level of p<0.01 (of 10 months, 1 year, and 2 years) in the monthly variation of the mean water level of the reservoir, and two main periodicities with a significance level of p<0.01 (at 6 months and 2 years) in the monthly number of earthquakes. By decomposing the monthly earthquake counts into intrinsic mode functions (IMFs) using the empirical decomposition method (EMD), we identified two IMFs characterized by cycles of 10 months and 2 years, significant at the 1% level, and one cycle of 1 year, significant at the 5% level. The cycles identified in these two IMFs are consistent with those detected in the water level, showing that, in a rigorously statistical manner, the seismic process occurring in the Lai Chau area might be triggered by the loading–unloading operational cycles of the reservoir.

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“…This could indicate a significant redistribution of mass around the active faults intersecting the area, which may have some interaction with seismic activity. Seasonal variations in the level of Lake Nasser are likely to change the stress regime in the area and, therefore, changes in the gravitational field and crustal deformations are reasonably expected (Saleh et al, 2018;Telesca et al, 2012Telesca et al, , 2017; see also Johnson et al, 2017 for loading effects on Californian faults.…”

Section: Previous Gravity Studies On the Areamentioning

confidence: 99%

A First Reliable Gravity Tidal Model for Lake Nasser Region (Egypt)

Riccardi

Hinderer

Zahran

et al. 2022

Pure Appl. Geophys.

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In the framework of the French–Egyptian Imhotep Project, two spring gravimeters have been installed in the area of Lake Nasser (Egypt) with the aim to establish a first reliable gravity tide model for the region. The two tidal gravity stations are located in Aswan, on the northern edge of the lake and in Abu Simbel in the south, respectively. This study was mainly aimed to obtain a reliable model of the crustal response to tidal forces and, consequently, to increase the accuracy of the geodetic observations, to be used in future geophysical studies in this region as well as to investigate the effect of the Lake level variations on the crustal deformation and related gravity changes. Nearly 3 years of gravity records (from May 2018 to April 2021) were collected. Since no scale factor was available for the two gravimeters, the first step of this study was to achieve a reliable calibration for each of the two collected gravity signals. After removing the instrumental drift, spikes, steps and tares, both gravimeters have been calibrated by fitting the output signal against a synthetic reference signal based on the body tidal gravity response due to Wahr-Dehant Earth model and FES2014 ocean tidal loading model. The calibrated signals have been analyzed with ET34-X-V80 software for tidal analyses. This enabled us to retrieve a set of frequency-dependent gravity factors (amplitude and phase) for the main tidal waves, as well as to obtain gravity residuals. It turns out that the accuracy of the amplitude estimates for the main tidal waves is 0.2 ÷ 1% for LCR_ET16 in Aswan and 1 ÷ 10% for the LCR_D-218 in Abu Simbel. To improve the tidal model at Abu Simbel, LCR_ET16 was stopped in Aswan and relocated there. The first 90 days of gravity recordings from ET16 at Abu Simbel provide promising results, with an accuracy of the order of 0.1% for the main tidal waves, even better than the results obtained in Aswan. The residual gravity signal after tidal subtraction at Aswan is in the range of ± 50 µGal. Further analyses of the instrumental contribution are however needed before to be able to interpret this gravity signal in terms of surface loading (i.e. changes in the water level of Lake Nasser) or underground hydrology.

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Analysis of the cross-correlation between seismicity and water level in the Aswan area (Egypt) from 1982 to 2010

Cited by 18 publications

References 10 publications

Time clustering of wave storms in the Mediterranean Sea

Time clustering of wave storms in the Mediterranean Sea

Fractal and Spectral Analysis of Seismicity in the Lai Chau Area (Vietnam)

A First Reliable Gravity Tidal Model for Lake Nasser Region (Egypt)

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