Research

Contact information

Institute office:
PL 68 (Gustaf Hällströmin katu 2b)
00014 University of Helsinki
Finland

phone +358-(0)9-1911
fax +358-(0)9-191 51598

 

 

Structure of lithosphere

mapFigure: Refraction and reflection seismic surveys in Finland during 1979-2003

Seismic methods are the most efficient ways to study the deep interior of the Earth. The crust, the uppermost part of the Earth, can extend down to the depth of 60 km. The thickness of the crust can be determined by deep seismic soundings. In refraction soundings refracted and in wide angles reflected waves from inner boundaries are utilized, while in reflection soundings the waves reflecting almost vertically from boundary surfaces are used. Sources for seismic waves can be explosions, vibrators placed on trucks or air-guns trailed by a research vessel. The seismic waves propagating through the crust are recorded by geophones on the earth or by underwater hydrophone chains. Studies on crustal structure can also be performed by passive tomographic methods in which mining explosions and earthquakes are exploited. Using these it is possible to achieve insight into the mantle beneath the crust. The field surveys are usually performed as international cooperations as they involve several employees, equipment, and extensive know-how. The bedrock of Finland has been widely explored by seismic soundings, lately in FIRE-reflection sounding project.

 

Research projects

Reflection seismics
FIRE - Reflection seismics (Pekka Heikkinen, Annakaisa Korja, Timo Tiira & Jukka Keskinen)
Geophysical reseach at the northern part of Baltic Sea
BABEL - Reflection and refraction seismics (Pekka Heikkinen, Annakaisa Korja)

Refraction seismics in Finland
BALTIC (Pekka Heikkinen, Urmas Luosto)
FENNIA (Pekka Heikkinen)
POLAR (Pekka Heikkinen)
SVEKA (Pekka Heikkinen)
The structure of Mantle

Refraction seismics abroad
CELEBRATION
EUROBRIDGE
ALP
LT-7
POLONAISE
SUDETES
TTZ
FENNOLORA
CABLES

Passive seismic experiments abroad
ALPASS
PASSEQ 2006-2007
DANUBE 2004

Tomography and anisotrophy projects
EUROPROBE/SVEKALAPKO - Seismic tomography and anisotrophy
Tomographic imaging of seismic velocity structure beneath southern and central Finland

Other projects
Stabilization processes of Precambrian continental crust
3-D raytracing and visualization of deep seismic soundings
Interactive 3-D seismic and other geophysical data visualization tool