Human health may be at risk from long-term exposure to air pollution below current air quality standards and guidelines

Growing evidence that current pollution standards are insufficient and need to be revised, suggests study

Peer-Reviewed Publication

BMJ

Long-term exposure to air pollution appears to still be linked to higher mortality despite the existence of air quality standards that restrict levels of pollution, suggests a study published online in The BMJ today.

Researchers found evidence of higher death rates amongst people who had been exposed to more air pollution even though the levels were allowed under current official standards.

Previous studies have found an association between long term exposure to outdoor air pollution such as those in the form of fine particles in the air (known as particulate matter or PM2.5) and nitrogen dioxide (NO2) and poor health or death. 

Air pollution concentrations have fallen substantially in Europe since the 1990s, but it is unclear whether there still is a link between pollution and ill health or death at concentrations of pollution that are below current permitted limits.

Therefore, an international team of researchers led by the Institute for Risk Assessment Sciences at Utrecht University in the Netherlands, set out to investigate if there was an association between low levels of air pollution concentrations and natural and cause specific deaths.

Low level air pollution was defined as concentrations below current limit values as set by the European Union, US Environmental Protection Agency and the World Health Organization (WHO) air quality guidelines.

The researchers analysed data on eight groups of people within six European countries – Sweden, Denmark, France, the Netherlands, Germany and Austria – totalling 325,367 adults collectively.

Their study, known as the Effects of Low-Level Air Pollution: A Study in Europe (ELAPSE) recruited participants in the 1990s or 2000s.

Of the 325,367 participants who were followed up over an almost 20-year period, around 14.5% (47,131 people) died during the study period.

Analysis of the results showed that people who had higher exposure to particulate matter (PM2.5), nitrogen dioxide, and black carbon were more likely to die. 

An increase of 5 µg/m3 (a concentration measure of particulate matter) in PM2.5 was associated with a 13% increase in natural deaths while the corresponding figure for a 10 µg/m3 increase in nitrogen dioxide was 8.6%. Associations with PM2.5 and nitrogen dioxide were largely independent of each other.

Moreover, associations with PM2.5, nitrogen dioxide, and black carbon remained significant at low to very low concentrations.

For people who were exposed to pollution levels below the US standard of 12 µg/m3, an increase of 5 µg/m3 in PM2.5 was associated with a 29.6% increase in natural deaths. People exposed to nitrogen dioxide at less than half the current EU standard of 40 µg/m3, a 10 µg/m3 increase in nitrogen dioxide was associated with a 9.9% increase in natural deaths.

This is an observational study, and as such, can’t establish cause.

The study also has some limitations, say the authors, such as the fact that it focused on exposure in 2010 which was towards the end of the follow-up period for most participants and, given the downward trend in air pollution, this measure might not exactly reflect the concentrations experienced during follow-up.

However, this was a large study from multiple European groups of people with detailed information provided.

As such, the authors conclude: “Our study contributes to the evidence that outdoor air pollution is associated with mortality even at levels below the current European and North American standards and WHO guideline values.

“These findings are therefore an important contribution to the debate about revision of air quality limits, guidelines and standards, and future assessments by the Global Burden of Disease [study].”

[Ends]

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JOURNAL

BMJ

DOI

10.1136/bmj.n1904 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Long term exposure to low level air pollution and mortality in eight European cohorts within the ELAPSE project: pooled analysis

ARTICLE PUBLICATION DATE

31-Aug-2021

Less air pollution and more access to green or blue spaces: A recipe to improve the life quality of people with COPD

Peer-Reviewed Publication

BARCELONA INSTITUTE FOR GLOBAL HEALTH (ISGLOBAL)

Air pollution and greater distance with green of blue spaces negatively impact the health-related quality of life in patients with chronic obstructive pulmonary disease (COPD), according to a new study led by the Barcelona Institute for Global Health (ISGlobal), an institution supported by ”la Caixa” Foundation. The findings highlight the need for implementing urban policies that improve the life quality of a great number of people living with respiratory diseases across the world.

The health-related quality of life has become one of the most relevant parameters to measure the progression of chronic obstructive pulmonary disease (COPD). “We know that several clinical and psychological factors can affect this parameter, but little is known on the effect of environmental factors,” explains Judith Garcia-Aymerich, ISGlobal researcher. Thus, Garcia-Aymerich and her team assessed, for the first time, the association between health-related quality of life and exposure to different environmental factors in over 400 COPD patients with different levels of disease severity, from moderate to high.

The patients, all of them residing in Barcelona, underwent a COPD assessment test and answered a clinical questionnaire. The research team determined the residential exposure of each patient to air pollutants (NO2, PM2.5 and PM10 fine particles, and PM2.5 absorbance), traffic noise, land surface temperatures, and distance to green or blue (water) spaces. They found that exposure to high levels of NO2 and PM2.5 absorbance (an indicator of black carbon emanating from combustion) were associated with worse assessment and mental health questionnaire scores. “This might be explained by the restorative effect of blue and green spaces, although it could also be related to the fact that these spaces encourage greater physical activity,” says Subhabrata Moitra, first author of the study. 

The authors acknowledge that, being a cross-sectional study rather than a longitudinal one, they cannot demonstrate causality, and that further studies are needed to better understand the contribution of each pollutant. “However, this study, performed for the first time on a Mediterranean population, provides evidence that air pollutants (particularly NO2 and black carbon) and the distance to green or blue spaces negatively affects the health-related quality of life in COPD patients,” says Garcia-Aymerich.

These results can help clinicians to provide recommendations that improve the quality of life of their COPD patients, for example by avoiding traffic zones or being close to blue and green spaces. They also underline the need to limit air pollution in cities and redefine urban policies that improve the quality of life of the great number of people who live with respiratory diseases across the world.

These findings are published shortly before the celebration of the European Respiratory Society Congress 2021, which will take place virtually September 5-8.

Reference

S Moira, M Foraster, A Arbillaga-Etxarri, et al. Roles of the physical environment in health-related quality of life in patients with chronic obstructive pulmonary disease. Env Res. Jan 2022, 11828. https://doi.org/10.1016/j.envres.2021.111828

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JOURNAL

Environmental Research

DOI

10.1016/j.envres.2021.111828 

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Roles of the physical environment in health-related quality of life in patients with chronic obstructive pulmonary disease

ARTICLE PUBLICATION DATE

7-Aug-2021

Safeguarding European wild pollinators

Grant and Award Announcement

PENSOFT PUBLISHERS

 

IMAGE: SAFEGUARD LOGO view more 

CREDIT: @SAFEGUARD PROJECT

Wild pollinators are a key part of European biodiversity and provide a wide range of benefits to crops, wild plants, and human wellbeing.

At the same time, wild pollinators face multiple threats in Europe and around the world, including climate change, land use and habitat loss. That is why pollinators are declining in number and diversity. The full extent of their decline, its complex causes and the most effective ways to respond to it are still not well understood.

Safeguard is a newly funded EU project receiving 7.8 million Euros from the European Union's Horizon 2020 research and innovation programme.

Safeguard aims to expand current assessments of the status and trends of European wild pollinators, including bees, butterflies, flies, and other insects. It will use research, knowledge synthesis and state-of-the-art models to reveal current and future impacts of pressures on wild pollinators, paying particular attention to emerging threats, how different threats interact, and what the long-term and cumulative effects are.

25 institutions from 15 countries will collaborate

A team of researchers, NGOs, industry and policy experts from 25 institutions spread across 14 European countries and China are joining forces to contribute to Europe’s capacity to reverse the losses of wild pollinators.

“This interdisciplinary project will make a significant contribution to the protection of pollinators and their functions in European ecosystems and has the potential to reinforce global initiatives that aim to halt biodiversity declines,” comments Safeguard coordinator Prof. Dr. Ingolf Steffan-Dewenter, head of the Department of Animal Ecology and Tropical Biology at Julius-Maximilians-Universität Würzburg in Bavaria, Germany.

CAPTION

Wild pollinators. Species in order of appearance: Macroglossum stellatarum, Macropis europaea, Polyommatus icarus.

CREDIT

@Wikimedia Commons

Reducing multiple pressures on wild pollinators 

Safeguard will conduct empirical research for systematic assessment of multiple threats to wild pollinators at scales from the local to global, and will provide an evaluation of what are the most effective ways to halt declines in different.

One of Safeguard’s objectives is to improve understanding of the diverse values of European pollinators and develop new and diverse approaches to benefit pollinators – from field to landscape scales, and across agricultural, natural and urban systems.

Mobilising concerted multiple actions

With the support of key stakeholders, Safeguard will co-develop an integrated assessment framework, including guides to decision makers, so our research insights can more effectively support evidence-based management and policy at national, European and global scales.

Safeguard will increase awareness of wild pollinators and their societal value, especially with the general public, industry, business and policymakers, in order to mobilise concerted multiple actions towards reversing wild pollinator decline across Europe.

Start of the Safeguard project

Safeguard will hold its official kick-off meeting between 7 – 9 September 2021. In an effort to provide a safe environment in the face of COVID-19, the start of the four-year project will take place in an entirely online environment.

 

Grim warning for Aussie species in conservation checklist

Peer-Reviewed Publication

UNIVERSITY OF QUEENSLAND

 

IMAGE: AERIAL SHOT OF DEFORESTATION IN DALY RIVER, NORTHERN TERRITORY IN 2008. view more 

CREDIT: CREDIT: JULIAN MURPHY/WWF-AUS

The first comprehensive list of the threats to Australia’s most endangered plants and animals reveals blunt news about the future for some of the country’s favourite species.

The University of Queensland-led study has compiled a data set, listing the threats to Australian species from habitat loss, fragmentation, and degradation.

Michelle Ward, a PhD candidate at UQ’s School of Earth and Environmental Sciences said while it painted a grim picture for many plants and animals, it was not all bad news.

“This information can improve the conservation of some of Australia’s most endangered plants and animals by providing conservation managers with more precise data to better direct their efforts,” Ms Ward said.

“The database has been distributed to federal and state governments and conservation groups like Birdlife Australia, World Wide Fund for Nature, and the Nature Conservancy, who are using it to help inform their conservation actions.

“It brings together knowledge from experts across Australia and it has a range of applications – not only to prioritise conservation work, but also to assess when developments might have significant impacts on species.”

The list includes an in-depth analysis of almost 1800 plants and animals listed as threatened under Australian Commonwealth law – including 1339 plants and 456 animals.

“More accurate conservation efforts are now possible due to the ability to categorise and address these threats facing our at-risk species,” Ms Ward said.

“Looking at the data, conservation managers can see that mitigating habitat loss, invasive species, and disease, while also improving fire regimes and curtailing the impact of climate change wherever possible is crucial for curbing species decline.”

Co-author Dr April Reside from UQ’s School of Agriculture and Food Sciences said it showed in stark detail that some species faced extensive threats.

“Before now we didn’t have comprehensive information on the threats to these species, and more importantly, the severity of those threats,” Dr Reside said.

“For example, the swift parrot is facing 17 different threats including habitat loss from logging and agriculture, invasive weeds, and the many and varying effects of climate change.

“So now we know the range of threats that need to be addressed to save this iconic bird.

“Similarly, koalas face nine threats including habitat loss from agriculture and urban development, dog attacks and disease.

“With this information, we are now better equipped to protect the plants and animals that we cherish so much in Australia.”

The study was carried out with the support of eight universities and seven conservation, environmental and ecological science organisations throughout Australia.

The research has been published in Ecology and Evolution (DOI: 10.1002/ece3.7920).

CAPTION

Mother and joey koala after deforestation of habitat.

CREDIT

Image credit: Briano/WWF-Aus

JOURNAL

Ecology and Evolution

DOI

10.1002/ece3.7920 

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

A national-scale dataset for threats impacting Australia's imperiled flora and fauna

Uncommon byproducts of organochlorine pesticides found in the liver of raptors

Peer-Reviewed Publication

EHIME UNIVERSITY

 

IMAGE: RAPTORS ARE TOP PREDATORS IN THE TERRESTRIAL FOOD WEB. HIGH ACCUMULATION LEVELS OF C15-BASED CHLORDANE BYPRODUCTS, HOMOLOGUES OF DDT METABOLITES AND POLYCHLORINATED TERPHENYLS IN THE LIVER OF RAPTORS SUGGEST HIGH BIOMAGNIFICATION POTENTIAL OF THESE TYPICALLY UNMONITORED CONTAMINANTS. view more 

CREDIT: © TATSUYA KUNISUE, EHIME UNIVERSITY

A research team in Ehime University, Japan conducted a comprehensive profiling of chlorinated and brominated compounds bioaccumulated in the liver of various wild bird species from Osaka, Japan in order to find potentially harmful but “hidden” contaminants. The team found a specific accumulation of several groups of typically unmonitored halogenated contaminants in raptors, including those so far never been reported in wild animals. The findings were published in Environmental Science & Technology on June 8, 2021.

Ecological risk assessment of halogenated contaminants is an important issue, as many of these chemicals persist in the environment, bioaccumulate through the food web, and can cause lasting adverse effects. Chemicals listed as persistent organic pollutants (POPs) under the Stockholm Convention—including legacy industrial chemicals such as polychlorinated biphenyls (PCBs) and legacy organochlorine pesticides such as dichlorodiphenyltrichloroethane (DDT) and chlordane, etc.—are monitored in the environment, animals, and humans by national and international programs, typically using chemical analysis targeting specific predetermined groups of POPs. However, conventional analytical methods cannot detect untargeted contaminants such as chemical synthesis byproducts, and environmental transformation products. There is increasing evidence for the occurrence of many typically unmonitored and unknown bioaccumulative contaminants in the environment and biota, but the accumulation levels and behavior of such POPs-like contaminants in various food webs remain unclear.

The research team in Ehime University used advanced analytical methods based on two-dimensional gas chromatography (GC×GC), time-of-flight mass spectrometry (ToFMS), and software mass spectral filtering for comprehensive profiling of chlorinated and brominated contaminants in the liver of terrestrial and brackish water bird species from Osaka, Japan. Relatively high levels of typically unmonitored halogenated contaminants, including polychlorinated terphenyls (PCTs), various DDT- and chlordane-related compounds, were found in raptors. Notably, chlordane byproducts with C15-based structures were detected for the first time in wild animals and showed high biomagnification potential in the terrestrial food web. These findings highlight the need for further studies on occurrence, structure elucidation and toxicological assessment of unmonitored POPs-like contaminants.

The study was part of an effort to build a complementary digital archive of comprehensive chemical screening data for a chemical monitoring repository for environmental and biological specimens (ChemTHEATRE, Ehime University).

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JOURNAL

Environmental Science & Technology

DOI

10.1021/acs.est.1c00357 

ARTICLE TITLE

Nontarget Screening of Organohalogen Compounds in the Liver of Wild Birds from Osaka, Japan: Specific Accumulation of Highly Chlorinated POP Homologues in Raptors

ARTICLE PUBLICATION DATE

7-Jun-2021

1. Bookchin M. Our Synthetic Environment - Libcom

   https://libcom.org/files/Bookchin M. Our Synthetic Environment.pdf · PDF file

   Our Synthetic Environment Murray Bookchin 1962 Table of contents Chapter 1: THE PROBLEM Chapter 2: AGRICULTURE AND HEALTH Chapter 3: URBAN LIFE AND HEALTH Chapter 4: THE PROBLEM OF CHEMICALS IN FOOD Chapter 5: ENVIRONMENT AND CANCER Chapter 6: RADIATION AND HUMAN HEALTH Chapter 7: HUMAN ECOLOGY Chapter 8: HEALTH AND SOCIETY Appendixes

Hurricane Ida ‘may be one of the best observed landfalling hurricanes’

Reports and Proceedings

UNIVERSITY OF OKLAHOMA

 

IMAGE: THE OU SMART RADAR WITH THE NOAA P3 HURRICANE HUNTER view more 

CREDIT: COOPERATIVE INSTITUTE FOR MESOSCALE METEOROLOGICAL STUDIES/NOAA

NORMAN, OKLA. – A research team led by Michael Biggerstaff, a professor of meteorology in the College of Atmospheric and Geographic Sciences at the University of Oklahoma, successfully captured data with mobile radars and other weather instruments as Hurricane Ida made landfall in Louisiana.

“The goal of this research, funded by the National Institute for Standards and Technology, is to capture the vertical profile, duration and gustiness of extreme winds in an effort to provide information that could improve building codes and mitigate damage to homes and commercial buildings,” Biggerstaff said.

The team captured unique datasets during the landfall of Hurricane Ida and as it transitioned into a tropical storm.

“Ida was undergoing an eyewall replacement cycle during landfall that caused the inner eyewall and associated wind field to weaken just before landfall,” Biggerstaff said. “The OU radar team observed the eyewall replacement process and how that process was impacted by increased surface friction during landfall.”

“Eventually, the outer eyewall dissipated, giving the inner eyewall an opportunity to increase in strength again as the eye was filling in to the west of New Orleans,” he specified. “This is the first time the process of an eyewall replacement cycle at landfall has been observed at such high temporal and spatial scales and should help improve forecasts of this process, which is responsible for significant changes in storm intensity over time scales of a few hours.”

Additionally, the SMART radars observed many mesovortices, small-scale rotational features found in convective storms, along the inner edge of the eyewall before, during and after landfall. This is the 13th landfalling hurricane Biggerstaff has studied with the SMART radars, including three deployments in Louisiana last year.

“Research from our deployment into Hurricane Harvey in 2017 shows these mesovortices can produce extreme wind gusts that add to the damage associated with the hurricane,” he said. “Moreover, these mesovortices help redistribute energy across the eyewall that affects both the strength and breadth of damaging winds.”

“Together with the additional effort of scientists from other universities, Hurricane Ida may be one of the best observed landfalling hurricanes to date,” he added.

CAPTION

OU graduate student Addison Alford is operating the radar.

CREDIT

Michael Biggerstaff, College of Atmospheric and Geographic Sciences, University of Oklahoma

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Hurricane Ida ‘May Be One of the Best Observed Landfalling Hurricanes’

ARTICLE PUBLICATION DATE

2-Sep-2021

Geologists look to past for answers on future tsunami threats

Peer-Reviewed Publication

VIRGINIA TECH

 

IMAGE: VIRGINIA TECH AND JAPANESE RESEARCHERS EXTRACT SEDIMENT CORE FROM THE KUJUKURI COASTAL PLAIN IN JAPAN. PHOTO COURTESY OF TINA DURA view more 

CREDIT: TINA DURA

Multiple large and destructive tsunamis in the past few decades in the Indian Ocean (2004), Chile (2010), and Japan (2011) have underscored the threat that tsunamis pose to coastal regions, ushering in a new era of research aimed at better predicting areas threatened by the fast-developing natural disasters.

But documenting and examining recent events does not provide enough information to fully characterize coastal hazards, said Tina Dura, an assistant professor of coastal hazards in Virginia Tech’s Department of Geosciences. Dura is taking a new approach to help overcome that information deficit. She’s looking at the past, with an aim to understand what may lie ahead.

“It is still too difficult to predict when a tsunami may strike if we only consider the recent past,” Dura said. “Some coastlines have not experienced a recent large tsunami, so we may underestimate the potential for infrequent, but large and destructive tsunami events,” Dura said. “We hope to change that by using geological history as our guide.”

In another study published earlier this year, Dura, along with Jessica DePaolis, a Ph.D. student in the Coastal Hazards Lab, discovered important geologic evidence along the coast of north-central Chile that should help improve earthquake and tsunami hazards assessments along this coastline. Robert Weiss and Ben Gill, also members of the Department of Geosciences, contributed to the study.

“This study describes the first geologic evidence of past tsunami inundation along the north-central Chile coast,” said Dura, who is an affiliated member of the Center for Coastal Studies at Virginia Tech. “Every new tsunami deposit we describe helps paint a more complete picture of how tsunamis have behaved in the past and what we can expect in the future.”  

Their findings were published in Quaternary Science Reviews, a peer-reviewed journal covering earth, climate, and life interactions.

“Visiting north-central Chile and seeing the tsunami evidence firsthand really drove home the power of this hands-on geologic effort to better understand tsunami hazards,” said DePaolis. “Leading the data collection and writing of the study was a big challenge but it was made possible by a great group of collaborators from Chile and the U.S.”

The study focuses on a region of north-central Chile that lies along an active portion of a subduction zone that has produced multiple earthquakes larger than magnitude 8 over the past century, often accompanied by tsunamis. However, a combination of several factors, including a semi-arid climate, sand-dominated coastline, and historically sparse population, has limited the historical (written and instrumental) and geologic records of tsunamis in this region. A recent magnitude 8.3 earthquake and accompanying tsunami in north-central Chile on Sept. 16, 2015, provided a unique opportunity to examine the nature of tsunami deposits in the region.

Dura’s Coastal Hazards Lab uses sand beds deposited by tsunamis and preserved in coastal environments to reconstruct past tsunami inundation over hundreds to thousands of years, helping better define coastal hazards in a region.

Dura was part of research that appeared in Nature Geoscience today examining seismic risk of earthquakes and associated tsunamis in the Tokyo region. They used a combination of geological evidence of tsunami inundation along with tsunami modeling to determine what plate boundaries past regional tsunamis have originated from. The work revealed that earthquakes along a previously unconsidered plate boundary have produced significant tsunami inundation in the past, adding another possible source for earthquakes in the Tokyo region and tsunamis in the Pacific Ocean.

The Coastal Hazards Lab group employed both field-based (stratigraphic mapping, sediment descriptions, surveying) and laboratory-based methods (particle size, geochemical, modeling, and dating analyses) to identify two anomalous sand beds in a coastal wetland in Tongoy Bay, north-central Chile. Satellite imagery taken before and after the 2015 earthquake, and post-earthquake surveys show the younger sand bed was deposited by the 2015 tsunami.

An older sand bed at the site was previously undocumented and was remarkably similar in composition to the 2015 tsunami sand bed. However, the older sand bed was slightly thicker and extended further inland than the 2015 tsunami sand, suggesting it was deposited by a larger event.

Radionuclide dating, which using cesium and lead to calculate the recent rate of sedimentation in the wetland, constrained the age of the older sand bed to 1922, when a large earthquake and tsunami occurred to the north of the study site. Analysis of historical maps showing the land use history of the wetland further supported the timing of sand bed deposition in the wetland to the early 20th century.

The discovery of a 1922 tsunami sand in north-central Chile shows that the 1922 tsunami produced significant inundation beyond the southern end of the earthquake rupture area. This provides additional insight into the type of ruptures that create high tsunamis along the north-central Chile coast. Dura said the results demonstrate that careful site selection and a multidisciplinary (e.g., stratigraphic, historical, and modeling) approach may help improve earthquake and tsunami histories along similar arid subduction zone coastlines.

“We need more studies like this; it’s a crucial step,” said Robert Weiss, director of Virginia Tech’s Center for Coastal Studies. “This is essential information that the Chilean government or the towns within the potentially threatened region could take action with to help mitigate the human toll of a tsunami.”

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JOURNAL

Nature Geoscience

DOI

s41561-021-00812-2 

ARTICLE PUBLICATION DATE

2-Sep-2021

Ground-breaking work from SFU identifies new source for earthquakes and tsunamis in the Greater Tokyo Region

Peer-Reviewed Publication

SIMON FRASER UNIVERSITY

 

IMAGE: JESSICA PILARCZYK AND COLLEAGUES FROM THE GEOLOGICAL SURVEY OF JAPAN CORE RICE PADDIES ON THE BOSO PENINSULA TO UNCOVER GEOLOGICAL EVIDENCE FOR A TSUNAMI FROM 1,000 YEARS AGO. view more 

CREDIT: SFU

Researchers have discovered geologic evidence that unusually large earthquakes and tsunamis from the Tokyo region—located near tectonic plate boundaries that are recognized as a seismic hazard source—may be traceable to a previously unconsidered plate boundary. The team, headed by Simon Fraser University Earth scientist Jessica Pilarczyk, has published its research today in Nature Geoscience.

The team’s ground-breaking discovery represents a new and unconsidered seismic risk for Japan with implications for countries lining the Pacific Rim, including Canada.

Pilarczyk points to low-lying areas like Delta, Richmond and Port Alberni as potentially vulnerable to tsunamis originating from this region.

In 2011, eastern Japan was hit with a massive magnitude 9 quake – creating the largest rupture area of any earthquake originating from the Japan Trench. It triggered the Fukushima Daiichi nuclear disaster and a tsunami that travelled thousands of miles away—impacting the shores of British Columbia, California, Oregon, Hawaii and Chile.

For the past decade, Pilarczyk and an international team of collaborators have been working with the Geological Survey of Japan to study Japan’s unique geologic history. Together, they uncovered and analyzed sandy deposits from the Boso Peninsula region (50 km east of Tokyo) that they attribute to an unusually large tsunami that occurred about 1,000 years ago.

Until now, scientists did not have historical records to ascertain if a portion of the Philippine Sea/Pacific plate boundary near the Boso Peninsula was capable of generating large tsunamis similar in size as the Tohoku event in 2011.

Using a combination of radiocarbon dating, geologic and historical records, and paleoecology, the team used 13 hypothetical and historical models to assess each of the three plate boundaries, including the Continental/Philippine Sea plate boundary (Sagami Trough), the Continental/Pacific plate boundary (Japan Trench) and the Philippine Sea/Pacific plate boundary (Izu-Bonin Trench) as sources of the 1,000-year-old earthquake.

CAPTION

Jessica Pilarczyk (SFU) and collaborator Tina Dura (Virginia Tech) sample sediment cores from rice paddies of the Greater Tokyo Region that contain evidence for an earthquake from 1,000 years ago that potentially originated from a historically unconsidered earthquake source.

CREDIT

SFU

Pilarczyk reports that the modeled scenarios suggest that the source of the tsunami from 1,000 years ago originated from the offshore area off the Boso Peninsula — the smallest of which (for example, possible earthquakes with the lowest minimum magnitude), are linked to the previously unconsidered Izu-Bonin Trench at the boundary of the Philippine Sea and Pacific plates.

“Earthquake hazard assessments for the Tokyo region are complicated by the’ trench-trench triple junction’, where the oceanic Philippine Sea Plate not only underthrusts a continental plate but is also being subducted by the Pacific Plate.”says Pilarczyk, an assistant professor of Earth sciences at SFU who holds a Canada Research Chair in Natural Hazards. ”Great thrust earthquakes and associated tsunamis are historically recognized hazards from the Continental/Philippine Sea (Sagami Trough) and Continental/Pacific (Japan Trench) plate boundaries but not from the Philippine Sea/Pacific boundary alone.”

Pilarczyk hopes that these findings will be used to produce better informed seismic hazard maps for Japan. She also says that this information could be used by far-field locations, including Canada, to inform building practices and emergency management strategies that would help mitigate the destructive consequences of an earthquake similar to the one of 1,000 years ago.

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JOURNAL

Nature Geoscience

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE PUBLICATION DATE

2-Sep-202