Conveners
P1.2 The Solid Earth and its Structure
- Onkgopotse Ntibinyane (CTBTO Preparatory Commission)
- Sherif Ali (CTBTO Preparatory Commission)
Description
E-poster session with display of each e-poster on an assigned touchscreen
We have compiled ground truth seismic events for the period of 2007-2024 that occurred within Australia. These events originated from either natural seismicity or mining-induced seismicity and mining blasts. Each event has been assessed on individual criteria, including the surface rupture, satellite imagery, temporary seismic installations or aftershock kits. GT events range from GT-1 to...
A new seismicity map for Kenya is compiled from nineteen catalogs with 7,726 events spanning 1895 to 2020. The magnitude ranges from Mw 2.5 to 7.0 and a b-value of 0.60, for three magnitudes of completeness (Mc) 3.1, 4.0, and 4.8. The seismicity reveals a complex and dense seismic activity across Kenya, where the South Kenya Rift and the Nyanza Rift have the highest seismicity trending...
In our present research, we have analysed and interpreted the aeromagnetic data and anisotropy of magnetic susceptibility (AMS) fabrics to highlight the structure and tectonic settings of the study area. We used horizontal gradient and tilt derivative to identify deep sources and faults. We applied the Euler Deconvolution technique to provide reliable information. The results indicated...
The Vrancea region is renowned for its intense seismicity, encompassing both crustal and intermediate-depth earthquakes derived from distinct sources. Crustal seismicity is primarily associated with the deformation of the overlying crust, while subcrustal earthquakes arise from a vertically extended source zone between 60 and 180 km within a sinking lithospheric slab. This unique region...
The Comoros Volcano Observatory has recorded significant seismic activity through the local seismic network in recent years. The evolution of the local seismicity, often assessed as volcano-induced seismicity, raises numerous inquiries on the seismo-volcanic hazards and the Magnitude records in the Comoro Archipelago. Data from the Karthala Volcano Observatory (KVO) bulletin between 2017 and...
We investigate seismic attenuation characteristics of the Charlevoix seismic zone that is located ~100 km downstream from Quebec City and is the most seismically active region of eastern Canada. We determine Coda Q using 583 earthquakes (2.0 ≤ M ≤ 5.4) recorded at seven stations of the Canadian National Seismic Network from 1992 to 2022. We find that the highest Q0 (Q at 1 Hz) values are at...
Tens of papers have reported small seismic events at shallow depth in and near the northern regions of the Democratic People’s Republic of Korea. They often characterize the events as aftershocks of specific nuclear test explosions (NTEs). Here, we report an analysis of about six years (2004 to 2010) of seismic data recorded by the Dongbei Seismographic Network (DBSN) that in addition to...
In this study, we developed a local magnitude scale for the southeastern region of Cuba—the part of the island exposed to the greatest seismic hazard due to its proximity to the Oriente fault system. From the 2011–2021 Cuban catalog, 7750 earthquakes with ML > 2 were selected, distributed in the region 19°–22° N, 73°–79° W, and recorded by at least four seismic stations within 500 km of the...
The growing interest in pulse-like ground motions, especially occurring near faults, stems from their potential to inflict significant structural damage due to distinct directivity and fling effects. This study seeks to enhance the identification and classification of these impulsive ground motions by integrating traditional data-processing methods with advanced machine learning techniques....
The East African Rift System (EARS) is a prominent continental rift zone, extending over 3000 km from the Afar Triple Junction to Mozambique. Its Kenyan segment features fault-bounded basins, volcanic activity and seismicity, making it an ideal site for investigating crustal structure and rifting mechanisms. Previous geophysical studies revealed significant variations in crustal thickness...
Probabilistic Seismic Hazard Assessments (PSHA) have not been conducted in large parts of Sub-Saharan Africa (SSA), due to incomplete earthquake catalogues, sparse seismic networks, etc; raising concerns on needed information for planning and disaster risk management. This study aims to bridge this research gap using modern techniques. Updated catalogue from Local Networks, significant data...
The Comprehensive Nuclear-Test-Ban Treaty (CTBT) Auxiliary Station AS41 in Jayapura plays a critical role in regional seismic monitoring as a broadband station. This study evaluates the data quality of AS41 using cross-correlation techniques to assess its performance relative to neighboring short period stations. The analysis highlights that AS41 records a significantly higher number of...
The devastating earthquake followed by the tsunami that occurred in Palu, Indonesia, on 28 September 2018 resulted in the death of more than 4300 people and serious damage to more than 12 000 buildings. Earthquake-induced site displacement is critical information for estimating the magnitude of earthquakes. Compared to a seismometer, which the signal clipping when recording in the near-field...
This study presents the development of a comprehensive fault database for Madagascar, created by integrating information from available geological surveys and published articles. We have compiled a detailed catalog of faults throughout Madagascar, incorporating data on fault geometry to determine size, length, and dip angle of the fault, and tectonic setting to identify the relative motions'...
It is well known that structures can be damaged by earthquake shaking caused by the rapid rupture of the fault, which releases the stored energy that can result in significant loss of life and property. For economical and hazard aspects, the general seismological laboratory, seismology department, NRIAG, made the first step of hazard mitigation and vulnerability of buildings and structures by...
We combine seismic and tectonic approaches to apply the empirical relationships between fault parameters and magnitudes to assess the maximum magnitude for the prediction of intensity motion. The Talysh area in southern Azerbaijan, with 3960 km², 38054'N and 48035'E, spreads to the north through the Alborz mountains of Iran. The earthquakes are concentrated mainly in the central part of the...
Oceanic transform faults are important tectonic structures connecting mid-ocean ridge sections, controlling their global morphology, movements, deformation, and rupture process. The complete understanding of these fracture zones relies on earthquake focal depth (Z) estimation. Z is a critical parameter for these tectonic studies that is usually difficult to estimate due to unfavorable...
Undoubtedly, the study of stress tensor inversion and the identification of the types of affected forces in any region are of paramount importance in the fields of seismology and earthquake hazard analysis. In this study, we comprehensively collected all available focal mechanism solutions for earthquakes in the vicinity of Egypt. Utilizing the Kagan angle to assess the homogeneity of the...
On 11 January 11 2022, a powerful 6.5 magnitude earthquake struck Paphos, Cyprus, affecting the broader eastern Mediterranean area. Recorded seismic activity at the AKMS station revealed a PGA of 296.496 cm/s² and a PGV of 5.573 cm/s, indicating intense shaking and rapid motion. Ground motion parameters, including intensity, perceived shaking, potential damage, PGA, PGV, and instrumental...
Global seismic models suffer from heterogenous source and receiver distributions. The greatest gaps are beneath the oceans, ~70% of the Earth's surface. Most teleseismically observed earthquakes occur at plate margins, while most seismic sensors are on land. Ocean Bottom Seismometers (OBSs) offer some improvement in sensor distribution, but OBS deployments are limited in extent and duration....
This poster aims to show the result and method of a study to improve the understanding of Jordan's crustal and upper mantle structure and enhance the local model velocity by integrating seismic data from local Jordanian stations, International Monitoring System (IMS) stations, and non-IMS stations. Building on my previous research titled "Integrate Data from IMS and Non-IMS Stations..." the...
Seismic arrays are known for their superior detection capabilities compared to single sensors. Array processing techniques, such as FK analysis, can estimate slowness and back azimuth, improving earthquake location estimates. However, these techniques require signal coherence across the array. Factors such as geological conditions and sensor spacing can lead to signal incoherence. Several...
The 5 January 5 1967 Mogod earthquake (Ms 7.5, Mw 7.1) in Mongolia caused significant surface faulting and has long been a focus of seismological studies. Recent collaborative research (2022–2024) between the Institute of Astronomy and Geophysics, Mongolia, and the Korea Institute of Geoscience and Mineral Resources (KIGAM) has advanced the understanding of this fault system. This study...
Tungurahua is one of the active volcanoes in Ecuador. It has an explosive period from 1999 to 2016. Instituto Geofísico Escuela Politécnica Nacional (IGEPN), Ecuador's geophysical institution, recorded Tungurahua's explosive activity. The data record included acoustic (infrasound) and seismic data. Researchers in vulcanology use the acoustic-seismic coupling method to study the behaviour of...
This study focuses on understanding the crustal and upper mantle structure beneath northern Egypt using seismic data from 500 records collected by the Egyptian National Seismological Network (ENSN). Two broadband stations in the region were used to investigate crustal properties through joint inversion of surface wave dispersion curves (Rayleigh wave phase velocity) and receiver functions...
An advanced analysis was conducted on the triggered 'non-volcanic' tremors (NVT) around Tambora volcano in West Nusa Tenggara, Indonesia by 35 teleseismic earthquakes with a magnitude M>7 and epicentral distance of over 1000 km between 2020 and 2022. The waveform data were taken from the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG). The identification of triggered...
Lg blockage occurs when the Lg phase has anomalously low amplitude compared to the Pg phase. This phenomenon is often observed for paths crossing oceanic crust, but it is also seen in some continental regions such as the Middle East. Lg blockage is problematic for explosion monitoring because Pg/Lg amplitudes are commonly used as a discriminant; therefore, Lg blockage can cause earthquake...
This study employs Grond, a probabilistic earthquake source inversion framework, to analyse moderate to strong earthquakes (Mw 3.5–6.4) in Albania and the surrounding region. Using seismic data accessed via FDSN and a locally developed velocity model, moment tensor inversion is conducted to characterize complex regional seismicity. While the analysis primarily focuses on natural seismic...
The Kumtor gold mine is located on the northwestern slope of the Ak-Shyirak ridge of the Central Tien Shan, at an altitude of 5200 m. Since 1997, the Kumtor has been carrying out commercial open-pit gold mining; several hundred open-pit blasts are carried out on its territory every year. In addition to blasts, tectonic earthquakes and landslides are recorded on the territory of the deposit....
The southern region of Brazil, comprising the states of Rio Grande do Sul (RS), Paraná (PR), and Santa Catarina (SC), exhibits low seismic activity compared to other regions of the country. However, it has experienced significant events over time. Notable earthquakes include a magnitude 5.9 event in 1939 on the continental margin, a magnitude 5.5 event in 1948 near the Uruguay border, and a...
From 27 September to 2 November 2024, a sequence of moderate earthquakes (magnitudes 4.2 to 5.3) occurred in the Fentale volcanic zone, Northern Main Ethiopian Rift. This region is characterized by active magmatism and volcanism, making it a critical area for studying tectono-volcanic interactions. The seismic events were localized near Fentale, an active stratovolcano, suggesting a potential...
In the Ionian Islands, historical records dating back to 1400 A.D. reveal a recurring pattern of large earthquakes (Mw>7.0) involving multiple fault rupturing, complex rupture dynamics, and/or the triggering of additional earthquakes. Efforts to mitigate future casualties and economic losses require detailed investigations into past destructive earthquakes and seismic hazard assessments at...
From 10 to 19 September 2024, residents of Mpape, a densely populated settlement in Abuja, Nigeria, with a high concentration of mining firms, witnessed a series of vibrations that they thought were from usual ground shakings resulting from regular quarry blasts. The duration (nine days) of the vibrations motivated this research to determine the seismotectonic nature and characterize...
We analyzed 2,853 seismograms from 294 earthquakes in northeastern Iran, with ML ranging from 1.5 to 5.5. Our findings indicate that at distances less than 71 km, corresponding to the attenuation of the direct seismic waves, horizontal components decay more rapidly (R-1.16) than the theoretical decay rate of 1/R. Between 71 and 151 km, where direct waves are joined by postcritical reflections...
The northernmost region of Aceh contains an active fault capable of releasing energy with significant magnitudes. The magnification energy released along this fault can trigger significant and destructive earthquakes. This is evidenced by the seismic history of the Seulimeum Fault (the northernmost fault) in 1964 (Setiyono et al., 2019), which recorded a magnitude of M 6.5. The earthquake...
This study investigates the spatial-temporal distribution of b-values along five fault areas the Judi fault, Thaple fault, Kathmandu fault, Motihari-Gauri Shanker fault and the Motihari-Everest fault following the Gorkha earthquake (MW 7.8). The study area spans the central Himalayas, bounded by latitudes 26.5°–29° N and longitudes 84°–87° E. An earthquake catalogue comprising 10 500 events...
Seismic location is a crucial problem in event monitoring and the research on improved location accuracy has been driven by efforts to effectively monitor the CTBT. Epicenter location accuracy is affected by many factors, including picking quality of seismic arrival times, accuracy of velocity model and distribution of seismic network. The accuracy of the velocity model will greatly influence...
The Aegean Sea is one of the key regions for the understanding of fundamental tectonic processes, including continental rifting. In addition, the continuous seismicity is attributed to its tectonic settings, which indicates the activities of these tectonics. Thus, tectonics and geodynamics of this region have always been the attention of many interested in earth sciences. Radar altimetry data...
An earthquake swarm is a series of seismic events that occur in a local area over a short period of time. For a cluster of moderate earthquake activities of the earthquake swarm to have occurred within few days before the main shock is unusual in the Solomon Islands seismic activities from past historical seismic data records. However, before the M8.0 earthquake that triggered a tsunami on the...
The Central Andes is a geologically complex region due to various tectonic processes, including extensional and compressional strains. This complexity is particularly evident in areas like the Bolivian Orocline, where a lack of geophysical equipment, such as seismic stations, often hinders studies related to tectonics and seismology. Despite this limitation, new methodologies have been...
The Oman National Bulletin produced by the Earthquake Monitoring Center, Sultan Qaboos University between 2014 and 2024 were combined with regional and teleseismic data from the International Seismological Centre bulletin. The resulting comprehensive bulletin contains 2994 events within our area of interest. We applied a two-step relocation procedure to improve the view of Oman’s seismicity....
The quality of seismic moment tensor catalogs is crucial for studying seismicity, active faults, seismic hazards and seismic risk assessment. The National Seismological Network of Colombia routinely and semi-automatically calculates centroid moment tensor (CMT) earthquake solutions with Mw > 4.2 using different full displacement waveform inversion methods. Recently, the Gisola software was...
Botswana is generally regarded as a seismically quiet region, characterized by low to moderate seismic activity. This relative stability is attributable to its location on the stable continental part of the African Plate, far from tectonic plate boundaries (Roger M Key and Neil Ayres, 1998). Nevertheless, on 3 April 3 2017, at 19:40:16.95 local time, an unexpected earthquake with a magnitude...
North Africa, which includes Egypt, Libya, Tunisia, Algeria, and Morocco, stretches from the Red Sea and Gulf of Aqaba in the east to the Atlantic Ocean in the west. This current study updates the seismic hazard evaluation for North Africa by applying a probabilistic approach. It uses an earthquake catalogue from 112 BC to 2024 AD and a seismotectonic model to assess seismic activity. The...
Studying the seismic risk of buildings and infrastructure in Kuwait is crucial for sustainability and urban development. The probabilistic seismic risk was computed to evaluate the economic and human loss in the Kuwait governorates of Al Farwaniyah, Mubarak Al-Kabeer, Sabah Al Ahmad, Hawally and Al Jahra to help emergency planners design plans to control or mitigate future risks. This study...
