Man made formations (strata) are widely distributed in urbanised and adjacent areas as result of anthropogenic activities during historical times and especially during intensive industrial development. Man made strata comprise cultural layers, landfills, waste management sites, abandoned industrial land, mine tailings, non-remediated pollution sites and other formations accumulated without proper environmental management, monitoring and treatment. The extent and thickness of man made strata in many places is unknown and/or poorly mapped. However, specific properties of the man made strata are clearly reported and documented, for instance in site investigation reports. These formations contain a variety of pollutants, and geotechnically are weak, unstable and unpredictable. They can be subject to severe liquefaction and landsliding during earthquakes. Therefore, man made strata are specific techo - geological formations with multiple problems and environmental implications, which must be better understood and managed.

 

 
 
 
New members should contact jonas.satkunas@lgt.lt

 

An International Workshop on Man-made strata and Geopollution, was held on June 18, 2011 at Katori-Narita, Chiba, Japan

 

The dramatic consequences of the Great Earthquake of 11 March 2011 (the Tohoku Earthquake), which with a magnitude of 9  and number of aftershocks hit a wide area of eastern Japan, was the main topic of the workshop. The earthquake caused extensive liquefaction-fluidization and land subsidence phenomena. The reason is that many industrial and urban areas of the Kanto Plain and Tokyo Bay are built on soft sediments of deltaic and lagoonal origin or land reclaimed along the ancient coastlineof the Tokyo

Bay. During the workshop 14 presentations were given on the man-made strata and

geopollution, medical geology and geological hazards. Extended abstracts of presentations  and materials of field trip are available on the website of IUGS-GEM (http://www.iugs-gem.org/Working-Groups). The field trip was guided by Hisashi Nirei, Kunio Furuno, Osamu Kazaoka and included observations of the consequences of the earthquake as well as geopollution sites. Professor Nirei proposed a declaration to draw awareness to the actions needed to reduce the impacts of future major earthquakes and of geopollution problems in Japan. All participants supported this declaration which is as follows:

 

 

 

                                    Katori-Narita-Itako  International Declaration

for deterring geological hazards such as those occurring in the 2011 Earthquake off the Pacific Coast of Tohoku

 

We, international researchers of man-made strata and geo-pollution, extend our sincere prayers for the resting in peace of the souls lost in the 2011 Earthquake off the Pacific Coast of Tohoku and our heartfelt wishes go to those hit by the disaster for the quickest possible recovery. We also extend our deepest sympathy to those who are suffering from effects of radiation pollution following the nuclear power plant disaster.

 

At the close of the International Workshop, we are setting out the following conclusions and proposals:

 

1.      The 2011 Earthquake off the Pacific Coast of Tohoku caused serious geological hazards, including large-scale liquefaction and fluidization in man-made strata formed by reclaiming land from the sea or valleys, and the calamitous tsunami along the coastline.  Man-made strata are abundant not only in Japan but also in the entire world. To reduce the further occurrence of damage in large-scale geological disasters in Japan we need to conduct detailed investigations of the Jinji unconformity i.e. the boundary discontinuity between man-made strata and natural strata, and the physical units within the man-made strata.

2.      In the 2011 Earthquake off the Pacific Coast of Tohoku , the tsunami which followed the earthquake generated tremendous geological hazards. We recommend the development of plans to evacuate people from the path of tsunami and to minimize damage. In areas with tsunami risk, people interested in tackling the local tsunami problems, including general residents, local historians, geologists, and tsunami researchers, should work together to identify record highest sea levels in the tsunami history of that area. The identified level must be agreed upon by the local authority and people in general. Once such a value is determined and agreed upon, it goes without saying that the local residents, particularly vulnerable people, should generally be relocated to higher places than the record level. Short-, medium- and long-term measures must be taken based on the agreed highest sea level while considering the benefits and costs of implementing the measures including impacts on the sea. Surveys of marine and coastal topography area are also needed to identify areas at maximum risk.

3.       For survey of radiation pollution resulting from damage such as that at the Fukushima Daiichi Nuclear Power Plant and implementing measures to deal with it, it is essential to take actions according to sound geoscience principles because of the movement of radioactive materials in the atmosphere and underground. We should measure radioactive materials according to the law of generation (decay), movement and deposition and take necessary actions. Scientific accuracy, democracy and openness are the key elements for such surveys and actions. This holds true for surveys and actions concerning all geopollution.

 

This questionnaire is aimed to generate an overview of man-made strata and geopollution in different countries

We kindly ask you to spend some minutes and provide us with the following information:

1. Is there information on, or estimates of the extent of, man made formations in your country? Please indicate any key references and /or data sources?

2. Could you please indicate the most relevant examples of urban geological mapping/data bases that deal with man made strata:

3. What are the typical cases of geopollution (types of pollutants) related to man made strata? Please provide any key references and /or data sources?

4. What are typical geohazards (landslides, subsidence, liquefaction phenomena etc) associated with  man made formations? Please provide any key examples and references?

5. Are there national /regional /institutional data bases or inventories of polluted sites? Please provide any key references and /or data sources?

6. Are there other environmental aspects of man made strata that you wish to indicate?\

7. Please provide your contact details for further communication:

Thank you very much indeed for your answers and information. We assure, the data you provided would be published with proper acknowledgement of your contribution. Please return this questionnaire to:  

 

IUGS –GEM Working Group on Man Made Strata and Geo-pollution
Secretary, Dr. Jonas Satkunas (Lithuania), e-mail: <jonas.satkunas@lgt.lt>