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 SeisTW - 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/ES304/MODULES/SEIS/NOTEOUT/seisoutline.html

Refraction seismics

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

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.