Seismic moment tensor (MT) inversions have become an important method for characterizing source type (e.g. earthquake, explosion, collapse), seismic moment and depth. However, these methods commonly use average plane-layered one-dimensional (1-D) Green’s functions (GF’s). For areas where path-specific structure is complex, 1-D GF’s cannot fit observed waveforms and source parameters from MT...
Data collected from IRIS Reviewed Bulletin for East Africa is used to generate empirical regression equations using orthogonal least square regression (OLSR). The regression best-fit line yields a regression equation y=0.517x+ 2.1787 with R2 0.6208 for 972 events with a cut-off magnitude of 2.5. While the R2 error is relatively high the result compare published regression equations. The slight...
We present a new 3-D shear velocity model for the crust-uppermost mantle structure beneath the Caribbean region from the surface down to 150 km depth. Our velocity model was derived from joint inversion of group and phase velocity dispersion data obtained from ambient noise and earthquake data. The group and phase dispersion curves estimated from ambient noise were calculated from...
Geophysical data has been gathered to assess these data sets to achieve reliable earthquake re-localisation. These data would serve as input for the Regional Seismic Travel Time (RSTT ) global model's workflow to achieve accurate RSTT in Venezuela and the Venezuelan part of the Caribbean Sea. Therefore, the data sets are extensive including the compilation of earthquakes, mine blasts and...
Unknown to the most Egyptians, of all natural hazards earthquakes pose the greatest damage potential. Large scale events are fortunately quite rare, however, if they strike, they can cause far reaching and very costly damage, which lead to potentially hundreds or even thousands of fatalities. So far, earthquakes cannot be prevented or even reliably predicted. But, due to extensive research,...
The recent strong densification of seismic networks and the increase of data availability from different type of sensors/networks (low-cost, Raspberry-shake, temporary deployments with hundreds of nodes, etc.) questions our ability to automatically and accurately detect, locate and characterize seismic events combining these composite and large data sets. These steps are however key issues to...
This research presents seismic studies review through history up to contemporary days to understand the behavior of earthquake occurrences in Azerbaijan and the interrelation between geodynamics and seismicity. Azerbaijan is situated within the central part of the Mediterranean active belt with seismicity stipulated by intensive geodynamic interrelation of Eurasian and Arabic lithosphere...
Sabah is the most seismically active state in Malaysia where it has recorded higher number of moderate seismological activities for the past decades. The seismicity map of Sabah shows the presence of two zones of distinctive seismicity, which are Ranau in Kota Kinabalu and Lahad Datu in the southeast of Sabah. The International Monitoring System (IMS) network set-up by the Comprehensive...
We report on advances in capabilities toward detailed three-dimensional (3-D) density evaluation of shallow underground features. We are currently developing software to use a 3-D Geological Framework Model (GFM) to predict gravitational anomalies from underground structures such as faults, cavities or tunnels that might be detected with surface and/or subsurface gravity measurements. This...
This research is to study earthquakes strong motion. According to the fact that the factor affecting peak ground acceleration (PGA) is distance, measurement PGA of earthquakes events were collected and have been selected and analysed to find the ground motion prediction equation (GMPEs) in Thailand to estimate seismic hazard or an effected area during a future earthquake in Thailand. The...
Jordan seismic activities are attributed to the Dead Sea Fault. It is an active transform fault extended from the Red Sea to the Taurus/Zagros Mountains. In cooperation with the Comprehensive Nuclear-Test-Ban Treaty Organization we used available local data, IMS data, and arrival times of seismic events with a magnitude greater than 3.5 to be able to validate the location accuracy. The...
The objective of this study is to characterize the recent stress distribution on the Main Marmara Fault (MMF) through quasi-static modeling of inter-seismic strain accumulation by considering past earthquakes and heterogeneous interseismic coupling. Since the MMF is prone to creating large earthquakes, it is crucial to infer the state of stress on the fault. The obtained pre-stress...
The current manuscript comes to answer a controversial question: Is the local earthquake activity in Kuwait a result of tectonic circumstances or anthropogenic? Kuwait is an oil-producing country from which oil is extracted in many places and earthquakes occur simultaneously with the extraction of oil. Seismic activity inside Kuwait is monitored with high accuracy and continuously after the...
The primary seismic station PS14-ROSC is located near the town of Rosal in the central part of the eastern cordillera, close to the Colombian National Seismological Network headquarters. The signal to noise ratio of seismic data shows low quality data. Using the power spectral densities (PSD), we analysed changes in the seismic background noise levels in the station. We integrated microtremor...
Variations in strain/stress and fluid content can change seismic velocities in the subsurface. Monitoring velocity changes, e.g. using ambient seismic noise, may thus constrain these variations as well as the material elastic properties and their non-linear behaviour. In our study we investigate variations of seismic velocity on a short time scale. We use coda wave interferometry to inspect...
Crustal rocks containing cracks and other internal flaws are characterized by nonlinear elasticity, a phenomenon that can be observed in laboratory experiments under applied stress. Stress sensitivity of elastic moduli is associated with opening/closing of cracks under applied stress. In this study we emulated rock laboratory protocols by measuring elastic wave speed using empirical Green’s...
The purpose of this study is to improve the hazard model and the accuracy of the Romanian earthquake catalogue (ROMPLUS) by determining the one-dimensional (1-D) velocity model in a complex collision setting at the bending of Southern Carpathians. To achieve this aim, we investigate 314 low to moderate-sized local, crustal events (Mw 1.0 - 3.4) that occurred from 2019 to 2021. The waveforms...
Seismic hazard assessment for Madagascar based on probabilistic analysis method (PSHA) is carried out after determining the three main parameters such as the mean seismic activity rate (λ), the b-value called Gutenberg-Richter value, and the maximum magnitude mmax. An earthquake catalogue was compiled from data combined between two sets of bulletins by the MACOMO and National Data Centre...
This study aims to estimate earthquake magnitude quickly using vertical component data from Broadband seismographs for the improvement of tsunami warnings. Empirical relationships were obtained for displacement and integrated displacement with moment magnitude. Data selection of seismic records was done before estimating the relationships of amplitudes by observing the number of amount of data...
The conventional picture of the seismicity in Finland, and the rest of Fennoscandia, has been that earthquakes are mostly individual or doublet events without fore or aftershocks. This notion of apparent singularity is based on automatic detection and classification tools and manual analysis workflow designed for regional events visible on multiple stations over a relatively sparse seismic...
The San Miguel volcano is considered one of the most active volcanoes in El Salvador due to its multiple eruptions; however, its structural properties are not fully understood. Four broadband seismometers were deployed by the Ministry of Environment of El Salvador from February 2014 to April 2014. We analysed ambient noise data using the spatial autocorrelation (SPAC) method and seismic...
Ghana is positioned far from any active plate boundaries at the southeastern part of the West African Craton. Elmina, Cape Coast, Saltpond, and Winneba are the four main towns located along the coast of Central region, being one of Ghana's sixteen regions. The seismicity in the regions are stable, with the exception of Greater Accra, Eastern, and part of Volta region that are notable...
Seismic site effect is a dominant parameter of seismic hazards analysis. We present an experimental study of microtremor data to investigate the dynamic characteristics of soil and structures at the Chiang Mai basin, Northern Thailand. The Chiang Mai basin was constructed on terrace sediments and alluvium sediments. The horizontal vertical spectral ratio (HVSR) analyses of ambient noise data...
In 2018 a series of large damaging earthquakes in Lombok-Indonesia occurred close together, causing many casualties and property damage. Therefore, we conducted source models composed of asperities for the 2018 Lombok Earthquake sequence using strong motion data and estimated by the empirical Green’s function method. We simulated the target event with a smaller event in the surrounding area....
Seismic tomograms of the uppermost subcontinental lithosphere (USCL) beneath southern Africa are key to improving knowledge of the correlation between the surface geology and velocity anomalies in the region. The regional distribution of seismic wavespeed anomalies (SWAs) provides a means to delineate known structural features and to find new regions of SWAs within the model space. Delineated...
Java Island is an area with high earthquake activity, one of these activities is caused by the impact of the Indo-Australian Plate, which hits the Eurasian Plate, causing a subduction zone along Java Island. Besides the subduction route, Java Island also has earthquake sources from active faults. This study aims to image tectonic patterns based on the structure of wave velocity models. The...
The Caucasus region lacked a comprehensive catalog, despite its role in Arabia-Eurasia convergence between the Black and Caspian Seas. The Lawrence Livermore National Laboratory and the Institute of Earth Sciences (IES) at Ilia State University generated a new, comprehensive seismic catalog for the period from 1951 to 2019 for the Caucasus region by combining data in the IES bulletin with...
Aswan is a very important city located in the southern part of Egypt, with several cultural heritage sites and critical infrastructure, including the High Dam. The High Dam is located near one of the most seismotectonically active zones, the Kalabsha fault zone. This zone witnessed the strongest instrumental earthquake in Aswan in November 1981, with Mw = 5.8. The current study aims to study...
Seismic array was developed in 1960s mainly to enhance signal noise ratio. Since then many array have been deployed around the world with varying geometry and aperture length based on the purpose of study. Many seismic analyses techniques have been developed, such as beamforming and F-K analysis, in order to achieve the desired results from the data. Hoqain seismic array in Oman is one of the...
We investigated seismic attenuation characteristics of the Lower St. Lawrence seismic zone. This zone is located ~400 km downstream from Quebec City and is between the Quebec North Shore and the Lower St. Lawrence. Coda Q was determined using 847 earthquakes (2.0 ≤ M ≤ 5.1) recorded on ten stations of the Canadian National Seismic Network (CNSN) in Quebec from 1985 to 2022. We find that the...
El Salvador is located in northern Central America, along the Pacific Ocean margin. San Salvador is located in a region with a high rate of seismic activity, as it is part of the El Salvador Fault Zone (ESFZ). Currently, there is no detailed information on the stress and deformation regime in San Salvador. In this sense, the present project is oriented to the analysis of the local...
Romania's participation in the global system of verification of nuclear experiments by seismological means is carried out within the National Institute for Earth Physics by hosting the National Data Centre of Romania (ROM-NDC) and operating and maintaining the auxiliary seismic station Muntele Rosu (AS081, MLR) as part of International Monitoring System (IMS). The main purposes of this study...
Seismic data collected by the Costa Rican OVSICORI-UNA seismic network is used to study the spatiotemporal seismicity and tectonic, related with the Mw 6.7, 21 July 21:15:07, 2021 earthquake, located in the Panama Fracture Zone, 114 km south of the Burica Peninsula. In this zone the relative motion of the Cocos and Nazca plates, accommodates the stress mainly by right-lateral strike-slip...
Macro seismic intensities are a key factor to support the seismic hypocenter location, moreover, this kind of information contributes to sample the Mercalli Modified Intensities (MMI) felt in each city, which can vary along the earthquake ray path. In our country the MMI has been collected since the OSC-NDC foundation, however, over the last 20 years this task was discontinued due to the lack...
Location algorithms have relied on one-dimensional (1-D) velocity models for fast, seismic event locations. The fast computational speed of these models made them the preferred type of velocity model for operational needs. Three-dimensional (3-D) seismic velocity models are becoming readily available and usually provide more accurate event locations over 1-D models. The computational...
