scholarly journals Historical Earthquake Scenarios for the Middle Strand of the North Anatolian Fault Deduced from Archeo-Damage Inventory and Building Deformation Modeling

2020 ◽  
Vol 92 (1) ◽  
pp. 583-598
Author(s):  
Yacine Benjelloun ◽  
Julia de Sigoyer ◽  
Hélène Dessales ◽  
Laurent Baillet ◽  
Philippe Guéguen ◽  
...  
Keyword(s):  
Historical Earthquakes ◽  
Historical Seismicity ◽  
North Anatolian Fault ◽  
First Century ◽  
Building Vulnerability ◽  
Earthquake Scenarios ◽  
The North ◽  
Seismicity Catalog ◽  
Quality Ranking ◽  
The City

Abstract The city of İznik (ancient Nicaea), located on the middle strand of the North Anatolian fault zone (MNAF), presents outstanding archeological monuments preserved from the Roman and Ottoman periods (first to fifteenth centuries A.D.), bearing deformations that can be linked to past seismic shaking. To constrain the date and intensity of these historical earthquakes, a systematic survey of earthquake archeological effects (EAEs) is carried out on the city’s damaged buildings. Each of the 235 EAEs found is given a quality ranking, and the corresponding damage is classified according to the European Macroseismic Scale 1998 (EMS-98). We show that the walls oriented north–south were preferentially damaged, and that most deformations are perpendicular to the walls’ axes. The date of postseismic repairs is constrained with available archeological data and new C14 dating of mortar charcoals. Three damage episodes are evidenced: (1) between the sixth and late eighth centuries, (2) between the nineth and late eleventh centuries A.D., and (3) after the late fourteenth century A.D. The repartition of damage as a function of building vulnerability points toward a global intensity VIII on the EMS-98. The 3D modeling of a deformed Roman obelisk shows that only earthquakes rupturing the MNAF can account for this deformation. Their magnitude can be bracketed between Mw 6 and 7. Our archeoseismological study complements the historical seismicity catalog and confirms paleoseismological data, suggesting several destructive earthquakes along the MNAF, since the first century A.D. We suggest the fault might still have accumulated enough stress to generate an Mw 7+ rupture.

scholarly journals A short introduction to historical earthquakes in Libya

2009 ◽  
Vol 47 (2-3) ◽  
Author(s):  
A. S. Suleiman ◽  
P. Albini ◽  
P. Migliavacca
Keyword(s):  
Historical Earthquakes ◽  
Historical Seismicity ◽  
Historical Sources ◽  
Short Introduction ◽  
North Central ◽  
The North ◽  
Lack Of Information ◽  
Macroseismic Effects ◽  
Instrumental Recording ◽  
Earthquake Effects

As a result of the relative motion of the African and European plates, Libya, located at the north central margin of the African continent, has experienced a considerable intraplate tectonism, particularly in its northern coastal regions. If the seismic activity of the last fifty years, at most, is known from instrumental recording, macroseismic effects of those earthquakes which affected Libya in the past centuries are still imperfectly known. To try and partly overcome this lack of information, in this contribution we present a short introduction to historical earthquakes in Libya, focusing on the period up to 1935. According to the studies published in the last twenty years, the earliest records of earthquakes in Libya are documented in the Roman period (3rd and 4th century A.D.). There is a gap in information along the Middle and Modern Ages, while the 19th and early 20th century evidence is concentrated on effects in Tripoli, in the western part of nowadays Libya. The Hun Graben area (western part of the Gulf of Sirt) has been identified as the location of many earthquakes affecting Libya, and it is in this area that the 19 April 1935 earthquake (Mw = 7.1) struck, followed by many aftershocks. Further investigations are needed, and some hints are here given at historical sources potentially reporting on earthquake effects in Libya. Their investigation could result in the needed improvement to lay the foundations of a database and a catalogue of the historical seismicity of Libya.

3D Physics-Based Numerical Simulations of Ground Motion in Istanbul from Earthquakes along the Marmara Segment of the North Anatolian Fault

2020 ◽  
Vol 110 (5) ◽  
pp. 2559-2576 ◽  
Author(s):  
Maria Infantino ◽  
Ilario Mazzieri ◽  
Ali Güney Özcebe ◽  
Roberto Paolucci ◽  
Marco Stupazzini
Keyword(s):  
Numerical Simulations ◽  
Ground Motion ◽  
Prediction Models ◽  
Seismic Source ◽  
North Anatolian Fault ◽  
Empirical Prediction ◽  
Earthquake Scenarios ◽  
The North ◽  
Specific Geometry ◽  
Directivity Effects

ABSTRACT In this article, the outcomes of a research cooperation between Politecnico di Milano, Italy, and Munich RE, Germany, aiming to improve ground-motion estimation in the Istanbul area through 3D physics-based numerical simulations (PBSs), are illustrated. To this end, 66 PBSs were run, considering earthquake scenarios of magnitude ranging from Mw 7 to 7.4 along the North Anatolian fault (NAF; Turkey), offshore Istanbul. The present article focuses on the detailed introduction of the simulated scenarios comprising: (1) the setup of the 3D numerical model, (2) the validation of the model with recordings of a recent earthquake, (3) the PBSs results, (4) a parametric study on the effect of different features of the seismic source, and (5) a comparison with well-established ground-motion prediction equations to highlight the main differences resulting from the use of a standard empirical approach as opposed to physics-based “source-to-site” numerical simulations. As a main outcome of this study, we observed as, for magnitude Mw 7 and 7.2, PBSs are in agreement with empirical prediction models whereas, for magnitude Mw 7.4, PBSs provide higher ground-motion estimates, as a consequence of directivity effects, amplified by the specific geometry of the portion of the NAF facing Istanbul.

scholarly journals GONAF – the borehole Geophysical Observatory at the North Anatolian Fault in the eastern Sea of Marmara

2017 ◽  
Vol 22 ◽  
pp. 19-28 ◽  
Author(s):  
Marco Bohnhoff ◽  
Georg Dresen ◽  
Ulubey Ceken ◽  
Filiz Tuba Kadirioglu ◽  
Recai Feyiz Kartal ◽  
...  
Keyword(s):  
Fault Zone ◽  
Historical Seismicity ◽  
North Anatolian Fault ◽  
Sea Of Marmara ◽  
North Anatolian Fault Zone ◽  
Recurrence Times ◽  
Geophysical Observatory ◽  
The North ◽  
Population Center

Abstract. The Marmara section of the North Anatolian Fault Zone (NAFZ) runs under water and is located less than 20 km from the 15-million-person population center of Istanbul in its eastern portion. Based on historical seismicity data, recurrence times forecast an impending magnitude M>7 earthquake for this region. The permanent GONAF (Geophysical Observatory at the North Anatolian Fault) has been installed around this section to help capture the seismic and strain activity preceding, during, and after such an anticipated event.

scholarly journals Archaeoseismological study of the Cherichira aqueduct bridge, Kairouan, Tunisia

2021 ◽  
Author(s):  
Klaus-G. Hinzen ◽  
Mustapha Meghraoui ◽  
Nejib Bahrouni ◽  
Yassine Houla ◽  
Sharon K. Reamer
Keyword(s):  
Plate Boundary ◽  
Flash Floods ◽  
Archaeological Sites ◽  
North African ◽  
Earthquake Scenarios ◽  
Mountain Ranges ◽  
The North ◽  
The Status ◽  
The City ◽  
Aqueduct Bridge

AbstractIn the past, several destructive earthquakes have occurred in the North African Atlas Mountain ranges located along the Africa–Eurasia plate boundary. Although the region is rich with impressive archaeological sites, including those in modern Tunisia, few comprehensive archaeoseismological studies have been conducted. Historic sources account at least three damaging earthquakes in the Kairouan area in central Tunisia between AD 859 and 1041. Little is known about which faults triggered these earthquakes or the size of these events. The water supply of the city of Kairouan depended on a 32-km-long aqueduct with a large bridge (now partially collapsed) at the confluence of the de Mouta and Cherichira rivers. The original bridge of Roman construction was retrofitted twice during the Aghlabid period (AD 800–903) and probably in AD 995 during the Fatimid period. The ruined section of the bridge shows damage which might be related to the AD 859 earthquake shaking. Here, we present a detailed study of the history, the status and the damage of the Cherichira aqueduct bridge using previous historic accounts and written works, a 3D laser scan model, local geological and seismological characteristics, and include results of radiocarbon dating and a timeline of events. In addition to earthquake ground motions, we consider severe flash floods on the bridge as a potential cause of the damage. We estimate the severity of such flash floods and develop a model with 18 earthquake scenarios on local reverse and strike-slip faults with magnitudes between MW 6.1 and 7.2. While a few damage patterns might be indicative of flooding, most damage can be attributed to earthquakes. It is highly probable that the earthquake in AD 859 caused enough damage to the Aghlabid bridge to render it dysfunctional; however, to resolve the question of whether another earthquake in AD 911 or 1041 caused the complete destruction of the previously retrofitted aqueduct by the Fatimids requires dating of additional sections of the bridge.

scholarly journals Recent Vs. Historical Seismicity Analysis For Banat Seismic Region (Western Part Of Romania)

2015 ◽  
Vol 11 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Eugen Oros ◽  
Mihai Diaconescu
Keyword(s):  
Active Tectonics ◽  
Historical Earthquakes ◽  
Historical Seismicity ◽  
Seismic Region ◽  
New Information ◽  
Macroseismic Effects ◽  
Hazard Sources ◽  
Earthquake Sequences ◽  
Seismicity Analysis ◽  
The City

Abstract The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania) and the historical seismicity of the region (Mw≥4.0). Four significant earthquake sequences have been recently localized in the region, three of them nearby the city of Timisoara (January 2012 and March 2013) and the fourth within Hateg Basin, South Carpathians (October 2013). These sequences occurred within the epicentral areas of some strong historical earthquakes (Mw≥5.0). The main events had some macroseismic effects on people up to some few kilometers from the epicenters. Our results update the Romanian earthquakes catalogue and bring new information along the local seismic hazard sources models and seismotectonics.

scholarly journals Repeated historical earthquakes in Sousse, Monastir and El-Jem (Tunisia)—an archaeoseismological study

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Miklós Kázmér
Keyword(s):  
Seismic Hazard ◽  
Active Faults ◽  
Historical Earthquakes ◽  
Segment Length ◽  
Seismic Events ◽  
Historical Buildings ◽  
The North ◽  
Sahel Region ◽  
The City ◽  
East West

AbstractTunisia is known of sparse and moderate earthquakes. However, there are seismically damaged historical buildings in the eastern Sahel region. The Roman amphitheatre of Thysdrus (modern El-Jem), various Islamic religious and secular buildings in Sousse and Monastir testify to seismic events with intensity up to IX (EMS98 scale). We raise the hypothesis that their destruction was caused by the nearby east-west Cherichira-Abaieh Fault and the north-south Monastir Fault. Simultaneity of the 859 AD Kairouan earthquake and extensive restoration works in Sousse 50 km to the east allow assessing magnitude up to 7.2 based on segment length. The city was hit both by the 859 AD and a post-1575 earthquake. Being nearby two active faults, seismic hazard in Sousse is higher than either in Kairouan or in Monastir.

scholarly journals New trenching results along the İznik segment of the central strand of the North Anatolian Fault (Turkey): an integration with preexisting data

2021 ◽  
Author(s):  
R. Civico ◽  
A. Smedile ◽  
D. Pantosti ◽  
F. R. Cinti ◽  
P. M. De Martini ◽  
...  
Keyword(s):  
Late Holocene ◽  
Historical Data ◽  
Historical Earthquakes ◽  
Fault Scarp ◽  
North Anatolian Fault ◽  
Natural Environments ◽  
The Past ◽  
The North ◽  
History Of ◽  
Central Strand

AbstractThis paper provides a new contribution to the construction of the complex and fragmentary mosaic of the Late Holocene earthquakes history of the İznik segment of the central strand of the North Anatolian Fault (CNAF) in Turkey. The CNAF clearly displays lower dextral slip rates with respect to the northern strand however, surface rupturing and large damaging earthquakes (M > 7) occurred in the past, leaving clear signatures in the built and natural environments. The association of these historical events to specific earthquake sources (e.g., Gemlik, İznik, or Geyve fault segments) is still a matter of debate. We excavated two trenches across the İznik fault trace near Mustafali, a village about 10 km WSW of İznik where the morphological fault scarp was visible although modified by agricultural activities. Radiocarbon and TL dating on samples collected from the trenches show that the displaced deposits are very recent and span the past 2 millennia at most. Evidence for four surface faulting events was found in the Mustafali trenches. The integration of these results with historical data and previous paleoseismological data yields an updated Late Holocene history of surface-rupturing earthquakes along the İznik Fault in 1855, 740 (715), 362, and 121 CE. Evidence for the large M7 + historical earthquake dated 1419 CE generally attributed to this fault, was not found at any trench site along the İznik fault nor in the subaqueous record. This unfit between paleoseismological, stratigraphic, and historical data highlights one more time the urge for extensive paleoseismological trenching and offshore campaigns because of the high potential to solve the uncertainties on the seismogenic history (age, earthquake location, extent of the rupture and size) of this portion of NAFZ and especially on the attribution of historical earthquakes to the causative fault.

scholarly journals Modelling ground motion in the Hutt Valley, New Zealand

2007 ◽  
Vol 40 (4) ◽  
pp. 190-199
Author(s):  
Shu Qin Ma ◽  
Martha Savage ◽  
Jiashun Yu
Keyword(s):  
New Zealand ◽  
Ground Motion ◽  
Synthetic Seismograms ◽  
Spectral Ratios ◽  
Amplification Factors ◽  
Earthquake Scenarios ◽  
Seismic Arrays ◽  
Ground Motion Amplification ◽  
The North ◽  
The City

The Hutt Valley is an alluvial basin that hosts the city of Lower Hutt, in the North Island, New Zealand. The basin is bounded by the Wellington Fault on its northwest side, and exhibits ground motion amplification factors up to about 15, measured by several seismic experiments using weak motion and portable seismic arrays during 1990-1991. Synthetic seismograms computed by using local 1D stratigraphic models under each station reproduce qualitatively the amplitudes and durations of the corresponding observed seismograms at most of the soft site stations of the arrays. Amplification factors estimated from spectral ratios of the synthetic seismograms are up to about 9. The authors present comparisons of amplification between synthetics and observations, allowing a “calibration” of the model so that it could be used to determine more realistic ground amplifications for earthquake scenarios.

Life of Ramanandi Centres in Varanasi

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Daniela Bevilacqua
Keyword(s):  
Nineteenth Century ◽  
Fifteenth Century ◽  
Religious Community ◽  
First Century ◽  
North West ◽  
The North ◽  
Ethnographic Data ◽  
The 1960S ◽  
Local Traditions ◽  
The City

The Ramanandi samprad?y is a Vaisnava religious order supposedly formed by Ramanand in Varanasi in the fifteenth century. The sampraday, nevertheless, primarily developed and spread in the north-west of India, and Ramanandi centres (re)appeared in Varanasi around the nineteenth century. Although renowned for its Saiva temples and ascetics, Varanasi, indeed, also manifests a Vaisnava nature. Referring to an inquiry on the ascetic groups present in the city led by anthropologists Sinha and Saraswati in the 1960s, this article focuses its attention on Ramanandis centres in the twenty-first century. Following the list of places provided by the two scholars, using local traditions and ethnographic data, the article provides glimpses into the life of ‘subaltern’ Ramanandi temples and asrams, showing how today the survival of local religious centres depends on the support of lay people, who may be attracted by devotion to specific places, but mostly by the charisma and the activities of their leaders and the religious community they are able to create.

scholarly journals Improving Urban Seismic Risk Estimates for Bishkek, Kyrgyzstan, Incorporating Recent Geological Knowledge of Hazards

2021 ◽  
Author(s):  
Ruth Amey ◽  
John Elliott ◽  
C. Scott Watson ◽  
Richard Walker ◽  
Marco Pagani ◽  
...  
Keyword(s):  
Residential Buildings ◽  
Active Faults ◽  
Active Faulting ◽  
Ground Shaking ◽  
Earthquake Scenarios ◽  
The North ◽  
Digital Elevation ◽  
Earthquake Model ◽  
Hazard And Risk ◽  
The City

Many cities are built on or near active faults, which pose seismic hazard and risk to the urban population. This risk is exacerbated by city expansion, which may obscure signs of active faulting. Here we estimate the risk to Bishkek city, Kyrgyzstan, due to realistic earthquake scenarios based on historic earthquakes in the region and improved knowledge of the active faulting. We use previous literature and fault mapping, combined with new high-resolution digital elevation models to identify and characterise faults that pose a risk to Bishkek. We then estimate the hazard (ground shaking), damage to residential buildings and losses (economical cost and fatalities) using the Global Earthquake Model OpenQuake engine. We model historical events and hypothetical events on a variety of faults that could plausibly host significant earthquakes. This includes proximal, recognised, faults as well as a fault under folding in the north of the city that we identify using satellite DEMs. We find that potential earthquakes on faults nearest to Bishkek - Issyk Ata, Shamsi Tunduk, Chonkurchak and the northern fault - would cause the most damage to the city. An Mw 7.5 earthquake on the Issyk Ata fault could potentially cause 7,900 ± 2600 completely damaged buildings, a further 16,400 ± 2000 damaged buildings and 2400 ± 1500 fatalities. It is vital to properly identify, characterise and model active faults near cities as modelling the northern fault as a Mw 6.5 instead of Mw 6.0 would result in 37% more completely damaged buildings and 48% more fatalities.

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