The susceptibility of #Oklahoma’s #basement to #seismic #reactivation (Nat Geosci., abstract)

[Source: Nature Geoscience, full page: (LINK). Abstract, edited.]

The susceptibility of Oklahoma’s basement to seismic reactivation

F. Kolawole, C. S. Johnston, C. B. Morgan, J. C. Chang, K. J. Marfurt, D. A. Lockner, Z. Reches & B. M. Carpenter

Nature Geoscience (2019)

 

Abstract

Recent widespread seismicity in Oklahoma is attributed to the reactivation of pre-existing, critically stressed and seismically unstable faults due to decades of wastewater injection. However, the structure and properties of the reactivated faults remain concealed by the sedimentary cover. Here, we explore the major ingredients needed to induce earthquakes in Oklahoma by characterizing basement faults in the field, in seismic surveys and via rock-mechanics experiments. Outcrop and satellite mapping reveal widespread fault and fracture systems with trends that display a marked similarity to the trends of recent earthquake lineaments. Our three-dimensional seismic analyses show steeply dipping basement-rooted faults that penetrate the overlying sedimentary sequences, representing pathways for wastewater migration. Experimental stability analysis indicates that Oklahoma’s basement rocks become seismically unstable at conditions relevant to the dominant hypocentral depths of the recent earthquakes. These analyses demonstrate that the geometry, structure and mechanical stability of Oklahoma’s basement make it critically susceptible to seismic reactivation.

Keywords: Geology; USA; Fracking; Earthquakes; Oklahoma.

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#Archaeological #evidence that a late 14th-century #tsunami devastated the coast of northern #Sumatra and redirected history (Proc Natl Acad Sci USA, abstract)

[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]

Archaeological evidence that a late 14th-century tsunami devastated the coast of northern Sumatra and redirected history

Patrick Daly, Kerry Sieh, Tai Yew Seng, Edmund Edwards McKinnon, Andrew C. Parnell, Ardiansyah, R. Michael Feener, Nazli Ismail, Nizamuddin, and Jedrzej Majewski

PNAS first published May 28, 2019 / DOI: https://doi.org/10.1073/pnas.1902241116

Contributed by Kerry Sieh, April 11, 2019 (sent for review February 8, 2019; reviewed by Roland J. Fletcher, Anthony J. S. Reid, and Ezra B. W. Zubrow)

 

Significance

We demonstrate that a tsunami in the late 14th century CE destroyed coastal sites along a critical part of the maritime Silk Road and set in motion profound changes in the political economy of Southeast Asia. Our results provide a precise chronology of settlement and trade along a historically strategic section of the Sumatran coast and are robust physical evidence for the rise of the Aceh Sultanate. Tragically, coastal areas impacted by the late 14th century tsunami were devastated by the 2004 Indian Ocean tsunami. This makes our findings relevant to debates about hazard mitigation and risk reduction. This example shows that archaeological, historical, and geological data are relevant in discussions about the long-term sustainability of communities exposed to geological hazards.

 

Abstract

Archaeological evidence shows that a predecessor of the 2004 Indian Ocean tsunami devastated nine distinct communities along a 40-km section of the northern coast of Sumatra in about 1394 CE. Our evidence is the spatial and temporal distribution of tens of thousands of medieval ceramic sherds and over 5,000 carved gravestones, collected and recorded during a systematic landscape archaeology survey near the modern city of Banda Aceh. Only the trading settlement of Lamri, perched on a headland above the reach of the tsunami, survived into and through the subsequent 15th century. It is of historical and political interest that by the 16th century, however, Lamri was abandoned, while low-lying coastal sites destroyed by the 1394 tsunami were resettled as the population center of the new economically and politically ascendant Aceh Sultanate. Our evidence implies that the 1394 tsunami was large enough to impact severely many of the areas inundated by the 2004 tsunami and to provoke a significant reconfiguration of the region’s political and economic landscape that shaped the history of the region in subsequent centuries.

tsunami – Sumatra – Aceh – postdisaster recovery – hazards

Keywords: Earthquakes; Tsunami; History; Society; Sumatra.

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#Slip on a mapped normal #fault for the 28th December 1908 #Messina #earthquake (Mw 7.1) in #Italy (Sci Rep., abstract)

[Source: Scientific Reports, full page: (LINK). Abstract, edited.]

Article | OPEN | Published: 24 April 2019

Slip on a mapped normal fault for the 28thDecember 1908 Messina earthquake (Mw 7.1) in Italy

M. Meschis,  G. P. Roberts,  Z. K. Mildon,  J. Robertson,  A. M. Michetti &  J. P. Faure Walker

Scientific Reports, volume 9, Article number: 6481 (2019)

 

Abstract

The 28th December 1908 Messina earthquake (Mw 7.1), Italy, caused >80,000 deaths and transformed earthquake science by triggering the study of earthquake environmental effects worldwide, yet its source is still a matter of debate. To constrain the geometry and kinematics of the earthquake we use elastic half-space modelling on non-planar faults, constrained by the geology and geomorphology of the Messina Strait, to replicate levelling data from 1907–1909. The novelty of our approach is that we (a) recognise the similarity between the pattern of vertical motions and that of other normal faulting earthquakes, and (b) for the first time model the levelling data using the location and geometry of a well-known offshore capable fault. Our results indicate slip on the capable fault with a dip to the east of 70° and 5 m dip-slip at depth, with slip propagating to the surface on the sea bed. Our work emphasises that geological and geomorphological observations supporting maps of capable non-planar faults should not be ignored when attempting to identify the sources of major earthquakes.

Keywords: Eartquakes; Geology.

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#Evidence of #supershear during the 2018 magnitude 7.5 #Palu #earthquake from space geodesy (Nat Geosci., abstract)

[Source: Nature Geoscience, full page: (LINK). Abstract, edited.]

Evidence of supershear during the 2018 magnitude 7.5 Palu earthquake from space geodesy

Anne Socquet, James Hollingsworth, Erwan Pathier & Michel Bouchon

Nature Geoscience (2019)

 

Abstract

A magnitude 7.5 earthquake hit the city of Palu in Sulawesi, Indonesia on 28 September 2018 at 10:02:43 (coordinated universal time). It was followed a few minutes later by a 4–7-m-high tsunami. Palu is situated in a narrow pull-apart basin surrounded by high mountains of up to 2,000 m altitude. This morphology has been created by a releasing bend in the Palu-Koro fault, a rapidly moving left-lateral strike-slip fault. Here we present observations derived from optical and radar satellite imagery that constrain the ground surface displacements associated with the earthquake in great detail. Mapping of the main rupture and associated secondary structures shows that the slip initiated on a structurally complex and previously unknown fault to the north, extended southwards over 180 km and passed through two major releasing bends. The 30 km section of the rupture south of Palu city is extremely linear, and slightly offset from the mapped geological fault at the surface. This part of the rupture accommodates a large and smooth surface slip of 4–7 m, with no shallow slip deficit. Almost no aftershock seismicity was recorded from this section of the fault. As these characteristics are similar to those from known supershear segments, we conclude that the Palu earthquake probably ruptured this segment at supershear velocities.

Synthetic aperture radar data were processed using GMTSAR software, freely available from https://topex.ucsd.edu/gmtsar/.

Optical satellite images were mosaicked using the Geospatial Data Abstraction Library (http://gdal.org) and then correlated using the COSI-Corr software package available at www.tectonics.caltech.edu/slip_history/spot_coseis/download_software.html.

Deformation generated by a static earthquake source was modelled using Okada57 equations implemented in the disloc program (www.physics.hmc.edu/GL/disloc/disloc.c).

 

Data availability

The data sets generated during the current study (displacement fields from Landsat-8, Sentinel-2 and WorldView image correlation and from the ALOS-2 interferogram, as well as the static slip distribution) are available from the corresponding author upon request. Raw satellite optical imagery was made freely available by ESA (Sentinel-2, https://scihub.copernicus.eu/dhus/#/home), USGS (Landsat-8, https://earthexplorer.usgs.gov/) and DigitalGlobe (WorldView, www.digitalglobe.com/opendata/indonesia-earthquake-tsunami/). Raw ALOS-2 data availability is restricted to PI investigation at www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm.

 

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Keywords: Earthquakes; Tsunami; Geology; Indonesia.

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#Earthquakes to #Floods: A Scoping Review of #Health-related #Disaster Research in Low- and Middle-income Countries (PLoS Curr., abstract)

[Source: PLoS Currents Disasters, full page: (LINK). Abstract, edited.]

Earthquakes to Floods: A Scoping Review of Health-related Disaster Research in Low- and Middle-income Countries

AUGUST 30, 2018 · REVIEW

AUTHORS: Catherine M. Tansey, John Pringle, Anushree Davé, Renaud Boulanger, Matthew Hunt

 

ABSTRACT

Introduction:

Health-related disaster research is a relatively small; but growing field of inquiry.  A better understanding of the scope and scale of health-related disaster research that has occurred in low- and middle-income countries (LMICs) would be useful to funders, researchers, humanitarian aid organizations, and governments as they strive to identify gaps, disparities, trends, and needs of populations affected by disasters.

Methodology:

We performed a scoping review using the process outlined by Arksey & O’Malley to assess the characteristics of peer-reviewed publications of empirical health-rFelated disaster research conducted in LMICs and published in the years 2003-2012.

Results:

Five hundred and eighty-two relevant publications were identified.  Earthquakes were by far the most commonly researched events (62% of articles) in the review’s timeframe.  More articles were published about disasters in China & South Asia/South East Asia than all other regions.  Just over half of the articles (51%) were published by research teams in which all the authors’ primary listed affiliations were with an institution located in the same country where the research was conducted.  Most of the articles were classified as either mental health, neurology and stress physiology (35%) or as traumatology, wounds and surgery (19%).  In just over half of the articles (54%), data collection was initiated within 3 months of the disaster, and in 13% research was initiated between 3 and 6 months following the disaster.  The articles in our review were published in 282 different journals.

Discussion:

The high number of publications studying consequences of an earthquake may not be surprising, given that earthquakes are devastating sudden onset events in LMICs.  Researchers study topics that require immediate attention following a disaster, such as trauma surgery, as well as health problems that manifest later, such as post-traumatic stress disorder.  One neglected area of study during the review’s timeframe was the impact of disasters on non-communicable and chronic diseases (excluding mental health), and the management of these conditions in the aftermath of disasters. Strengthening disaster research capacity is critical for fostering robust research in the aftermath of disasters, a particular need in LMICs.

FUNDING STATEMENT

Funding for this study was received from grant EOG 123679 from the Canadian Institutes of Health Research (principal investigator: Matthew Hunt). Dr. Hunt is supported by a Research Scholar Award from the Fonds de Recherche du Québec – Santé. At the time of working on the project, Renaud Boulanger was supported by a Master’s Award from the Fonds de recherche du Québec – Santé. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Keywords: Earthquakes; Floods; Environmental Disasters; Society.

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#Earthquake in Western #Iran: #Renovation Kills (PLoS Curr., abstract)

[Source: PLoS Currents Disasters, full page: (LINK). Abstract, edited.]

Earthquake in Western Iran: Renovation Kills

AUGUST 16, 2018 · RESEARCH ARTICLE

AUTHORS: Abbas Ostadtaghizadeh, Dr. Mona Khaleghy Rad, Hamidreza Aghababaeian, Mehdi Zare, Farnaz Kamranzad

 

ABSTRACT

Introduction:

Earthquake is the most important cause of death from natural disasters in Iran. This paper brings attention to the main causes of loss of life due to the Kermanshah province earthquake (Nov 12 2017), and provides a wakeup call about the unsafe nature of buildings there.

Methods:

This study is based on official reports review and a field assessment in the areas affected by the earthquake in western Iran.

Results:

Although buildings in this area are mainly old structures, strangely, more than 70% of the destroyed buildings in this earthquake were under 5 years of age, newly built or renovated buildings according to mandated building codes.

Discussion:

Mandated building codes and construction rules and regulations are not respected even for the newly constructed or reconstructed structures buildings.

Keywords: Earthquake, Iran, construct, reconstruct, Building codes

FUNDING STATEMENT

The authors received no fund for this study.

Keywords: Earthquakes; Mass Casualty Events; Iran; Society.

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The 2016 #Earthquake in #Ecuador: #Zika #Outbreak After a Natural #Disaster (Health Secur., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Health Secur. 2018 Mar 29. doi: 10.1089/hs.2017.0099. [Epub ahead of print]

The 2016 Earthquake in Ecuador: Zika Outbreak After a Natural Disaster.

Pacheco Barzallo D, Pacheco Barzallo A, Narvaez E.

 

Abstract

The objective of this work was to examine the spread of the Zika virus after the destructive impact of the earthquake of April 2016 along the coast of Ecuador. Using a difference-in-difference estimation method and a unique dataset to track Zika cases at the national level, we estimated the impact of the earthquake on the reported cases of Zika in the affected region. Our results suggest that the earthquake increased the reported cases of Zika by 0.509 per epidemiologic week (data per 10,000 population), and we argue that the destroyed built environment along with other factors created a disease focus, where the virus spread easily. Because of its potential complications and devastating long-term effects, Zika represents a national threat. After a natural disaster, the health authorities, together with a multidisciplinary team and the wider community, all have an urgent responsibility to collaborate to minimize the health risks to the population.

KEYWORDS: Disaster risk management; Epidemics; Infectious diseases; Public health; Zika virus

PMID: 29596013 DOI: 10.1089/hs.2017.0099

Keywords: Zika Virus; Earthquakes; Ecuador.

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