ABEM Distributor Seminar 2009 Terraloc Mk 8
ABEM Terraloc Mk 8
ABEM Terraloc Mk 8 • • Has a rugged aluminium case Is fully sealed with closed utility cover, Meets IEC IP 66 Can be used in heavy rain, snow and sleet Can also be used in dusty and sandy environments Also in cold, warm, dry or humid climate No built in printer and which means: • • – – • no ink problem no paper jam No openings for paper feed: no problem with gravel, sand, wooden pegs, ants, water, moisture and so on With a built in printer on service the complete instrument is on service
Terraloc Mk 8 • Is a competent stand alone seismograph no need for laptops in the field • Runs fully under Windows XP with the new acquisition software ABEM Seis. TW - Functionality of Windows is accessible also during measurements. • Communication is as simple as for a regular PC or laptop.
Terraloc Mk 8 • It has three USB connectors and a memory card reader
Terraloc Mk 8 • Before we look closer at the Terraloc and run its software a short run through of seismics. – What is seismics – What do we look at – For what is seismics used if we talk engineering
Seismics • Seismology is the study of earthquake vibrations as they travel through the Earth. It is widely used in the search for oil and gas reservoirs. • Seismic waves are vibrations within rock; they travel through the Earth like waves through the oceans. • Today we will focus on seismics for Near Surface Applications - engineering
Principles of Seismics • There are three types of seismic waves: – P wave, has a compressional longitudinal particle movement. – S wave, has a shear transversal particle movement. – Surface wave, has a circular particle movement. Only appears at the earths surface.
Example of a seismic wave and a seismic record
Methods • The dominating methods for registration of seismic waves are: – Refraction seismics, which utilises that the P wave travels faster along material contacts with a positive contrast, if contact is hit at a wide angle. – Reflection seismics, which utilises that the P wave will bounce against the same contact if at a narrow angle. – Direct seismics, borehole tomography is an example of this. The wave travels directly from the source to the receiver through the material. Surface seismics, a growing metod thanks to that it can utilize waves generated by noise.
Refraction Seismics
Refraction seismics
We recommed a look at a site were you will find some notes about refraction and reflection seismics. http: //www. earthsci. unimelb. edu. au/ES 304/MOD ULES/SEIS/NOTEOUT/seisoutline. html
Refraction seismics is the dominating method for engineering and other shallow investigations. It is straight forward to use and a good result can be acheived with a smaller system like 12 or 24 channels.
Reflection seismics is the dominating method when large depths are to be reached. Reflection seismics is the dominating method for oil and gas exploration. It demands more of the operator and the intrepretation software as well. It is 3 to 5 times more expensive compared to refraction seismics
Reflection seismics
Direct seismics Direct wave seismics basically consist of two types of mesurements: - Surface wave measurement: Deploys low frequency sensors. Waves only appears at the surface. A good method for passive seismics. - Cross hole tomography: Gives superior information about the velocity distribution between sensor and source holes.
Crosshole tomography
Applications & Examples • On the following frames will be shown a range of situations where Terraloc is put at work.
Subsurface studies for further development of the road network
Subsurface integrity studies and check of stabilisation efforts
Today many high power lines are put underground to clear land for development. Seismics is often used in preparation for trenching
Due to increased water levels and surface water flows SLOPE STABILITY has become an issue. Seismics is an exellent tool for Slope Stability investigations
Seismics and Geotechnics is complementing each other.
Need to dig further for the foundation? Again Seismics is an excellent tool
Continue your Seismic investigation through the transitional zone. Just a question of attaching the right cables and sensors to Terraloc
Thank you for the attention.
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