Resistivity survey has been carried out at Bestari Jaya (formerly known as Batang Berjuntai). Aim to detect the underground old river channel location. The survey was done using ABEM SAS4000 resistivity meter and ABEM LUND ES10-64 electrode selector system.

Let's Join Us!

Glad to announce that GTR with collaboration of Geology Programme, UKM are organizing TEM and MASW short course on 27th and 28th October 2014. Don't miss this opportunity!

For more information, you can download the short course template here.

Congratulation to our internship (LI) students from Geology Programme, UKM. Here, we present our gratitude to all of you. We hope all of  you get the best experience and knowledge while having internship here.

Thanks to :

1) Wan Sheba Farah Huda Binti Abd Karim    (Major: Petroleum Geology)

2) Nor Amalina Binti Mahyudin   (Major : Geo Tourism)

3) Bilal Al Farishi .      (Major: Petroleum Geology)

4) Muhammad Firdaus Bin Abd Saamad.   (Major: Environmental Geology)


We always welcome any university students who are looking for internship placement that taking courses related to our business.

Geo Technology Resources was listed in JMG Malaysia website as one of the geological investigation company. As our aim to be a fast leading company in geophysical and geotechnical sector, this will give us motivation and confident to our clients.

We also pleased to announce that, we were moving our office from Ipoh, Perak to Sepang, Selangor. Below is our new address:

Geo Technology Resources 
31-1 Jalan Mawar 5B,
Taman Mawar,
43900 Sepang,
Selangor,
Malaysia.

For any inquiries, don't hesitate to contact us.   

Land magnetometer used to collect magnetic total field data within the designated area. Data collected were essentially processed for diurnal and IGRF corrections, before other processing to bring out the best information from the data. This will lead to confident interpretation of iron ore deposits. Magnetic total field data was proven to be an effective tool for iron ore deposit mapping. The same magnetometer is also good for underground structure detection.

Resistivity survey is one of non-destructive method. Resistivity survey suitable for groundwater / aquifer detection. This geophysical method could be made near housing area without damaging personal property.  

Resistivity survey could be used to determine the depth of bedrock and mapped along the survey profile. The depth of penetration depends on the array / protocol used. For the depth of bedrock more than 70 m, pole-dipole array/protocol is the best option.

List below are the compilation of several surface geophysical methods. The guide for selecting geophysical methods provided by ASTM could be downloaded here. It is important to know which method should be used to successfully reached your target.


D420 Guide to Site Characterization for Engineering Design and Construction Purposes

D653 Terminology Relating to Soil, Rock, and Contained Fluids

D4428/D4428M Test Methods for Crosshole Seismic Testing

D5088 Practice for Decontamination of Field Equipment Used at Waste Sites

D5608 Practices for Decontamination of Field Equipment Used at Low Level Radioactive Waste Sites

D5730 Guide for Site Characterization for Environmental Purposes With Emphasis on Soil, Rock, the Vadose Zone and Ground Water

D5753 Guide for Planning and Conducting Borehole Geophysical Logging

D5777 Guide for Using the Seismic Refraction Method for Subsurface Investigation

D6235 Practice for Expedited Site Characterization of Vadose Zone and Groundwater Contamination at Hazardous Waste Contaminated Sites

D6285 Guide for Locating Abandoned Wells

G57 Test Method for Field Measurement of Soil Resistivity Using the Wenner Four-Electrode Method

2D Electrical Resistivity Imaging 

Resistivity imaging (also known as electrical resistivity imaging (ERI) or resistivity tomography (ERT) is one of the versatile geophysical method. Resistivity imaging measure the resistivity properties of the sub-surface by assessing the potential drops between electrodes in a variety of configurations, depends on the type of geophysical survey data required. Electrical resistivity surveys can be completed using multi-electrode consist of 41 electrode for 200 m cable and 61 electrode for 400 m cable. Therefore, an ERI survey line could extend up to 400m.

Low Cost of Survey/Exploration

Electrical resistivity imaging is one of the cost effective geophysical method. If compared to seismic refraction, GPR and other methods.

Versatile Geophysical Method

This method can be applied in most environment and engineering needs. Hilly area, open area, housing area, on concrete floor, tunnel, and etc. The list below is the example of capabilities of geophysical technique in solving environmental problems. Electrical resistivity imaging with IP (Induced Polarization which is part of resistivity method) could solve all the problems listed below.

List of environmental problems and methods that can be applied to solve the problem

Fast Data Processing

By using powerful inversion software, electrical resistivity data could be process as fast as possible after data acquisition at field. If compared to gravity, magnetic, seismic refraction and seismic reflection  methods, ERI is more time consuming. 

Interactive Result Display

Our clients satisfaction and understanding are our priority. Therefore, we try our best to give interactive result with professional explanation and interpretation.

An example of 2D Resistivity Imaging Result

Geofizik merupakan satu cabang ilmu berkaitan sifat-sifat fizik Bumi dan unsur-unsurnya. Penjelajahan struktur dan dinamik Bumi perlu menggunakan kaedah geofizik yang sesuai bergantung kepada sesuatu objektif penjelajahan.

Secara umum, kaedah geofizik merupakan satu kaedah yang berkos efektif dan tidak memusnah. Umum mengetahui bahawa maklumat subpermukaan bumi boleh diketahui dengan tepat melalui maklumat lubang gerudi. Namun begitu, berikutan maklumat lubang gerudi lebih terarah kepada maklumat secara setempat, ia tidak menggambarkan maklumat secara rantau.

Oleh kerana kos pengerudian yang tinggi, kaedah geofizik menjadi sandaran yang lebih baik dalam menyokong maklumat subpermukaan bumi. Hal ini kerana kaedah geofizik mampu meliputi kawasan yang luas untuk dijelajah. Kombinasi kedua-dua maklumat ini boleh memberi hasil yang sangat optimum.

Penyiasatan geofizik boleh diaplikasi dalam beberapa situasi kejuruteraan dan persekitaran. Antaranya ialah penjelajahan hidrokarbon, penyiasatan tapak kejuruteraan, pencemaran sisa, tinggalan arkeologi, air bawah tanah, penyiasatan rongga, sistem paip, kabel, dan laluan lombong bawah tanah juga dapat dikenal pasti menggunakan kaedah geofizik.

Selain membantu dalam penyiasatan awal aspek kejuruteraan, geofizik turut menyumbang dalam penyelesaian masalah sekitaran yang melibatkan pencemaran dengan memberi gambaran dan luas kawasan yang tercemar. Selain itu, ia mampu mengesan bahan tercemar dan sumbernya tanpa perlu teknik penggerudian. Seterusnya, pihak bertanggungjawab boleh mengambil tindakan susulan bagi merawat kawasan tercemar dan membendung pencemaran merebak ke kawasan yang lebih luas.

Kebanyakan kaedah geofizik yang biasa digunakan dalam penjelajahan turut berpotensi untuk digunakan dalam penyiasatan geosekitaran. Secara umum, kaedah geofizik menjadi amat penting dalam aspek pembangunan dan persekitaran. Tidak dapat dinafikan ia menjadi satu teknik yang sangat diperlukan seiring dengan kemajuan teknologi dan pembangunan yang pesat membangun demi mencapai keseimbangan persekitaran yang mapan.

Application

Seismic refraction method basically based on the measurement of the travel time of P-waves refracted at the interfaces between subsurface layers of different velocity.  Seismic energy is provided by a source ('shot') located on the surface. For shallow applications this normally comprises a sledgehammer and plate, weight drop or small explosive charge (blank shotgun cartridge). Energy radiates out from the shot point, either travelling directly through the upper layer (direct arrivals), or travelling down to and then laterally along higher velocity layers (refracted arrivals) before returning to the surface.

This energy is detected on surface using a linear array (or spread) of geophones (receiver sensor) spaced at regular intervals. Beyond a certain distance from the shot point, known as the cross-over distance, the refracted signal is observed as a first-arrival signal at the geophones (arriving before the direct arrival). Observation of the travel-times of the direct and refracted signals provides information on the depth profile of the refractor.

The primary applications of seismic refraction are for determining depth to bedrock and bedrock structure. Due to the dependence of seismic velocity on the elasticity and density of the material through which the energy is passing, seismic refraction surveys provide a measure of material strengths and can consequently be used as an aid in assessing rippability and rock quality. The technique has been successfully applied to mapping depth to base of backfilled quarries, depth of landfills, thickness of overburden and the topography of groundwater.

Procedure

Shots are deployed at and beyond both ends of the geophone spread in order to acquire refracted energy as first arrivals at each geophone position. Data are recorded on a seismograph and later downloaded to computer for analysis of the first-arrival times to the geophones from each shot position. Travel-time versus distance graphs is then constructed and velocities calculated for the overburden and refractor layers through analysis of the direct arrival and T-minus graph gradients. Depth profiles for each refractor are produced by an analytical procedure based on consideration of shot and receiver geometry and the measured travel-times and calculated velocities. The final output comprises a depth profile of the refractor layers and a velocity model of the subsurface.

Example of geophone spread 

The purpose of geoelectrical surveys is to determine the subsurface resistivity distribution by making measurements on the ground surface. From these measurements, the true resistivity of the subsurface can be estimated. The ground resistivity is related to various geological parameters such as the mineral and fluid content, porosity and degree of water saturation in the rock. Electrical resistivity surveys have been used for many decades in hydrogeological, mining, geotechnical, environmental and even hydrocarbon exploration (Loke et al. 2011).

The Resistivity Value of Earth Materials

Basically, igneous and metamorphic rocks typically have high resistivity values. Sedimentary rocks, which are usually more porous and have higher water content, normally have lower resistivity values compared to igneous and metamorphic rocks.The resistivity of groundwater varies from 10 to 100 ohm.m. Seawater has a low resistivity values which is 0.2 ohm.m.

after Loke 2013.

Reference: Loke, M.H. 2013. Tutorial : 2-D and 3-D electrical imaging surveys

Lubang benam atau turut dikenali sebagai "sinkhole" merupakan salah satu fenomena alam yang menyebabkan pemendapan tanah berlaku. Mungkin pada pengetahuan masyarakat setempat lubang benam ini dikenali sebagai tanah jerlus. Kebiasaannya, lubang benam ini terjadi dikawasan berbatu kapur. Sifat semulajadi batu kapur yang mudah terlarut (proses pelarutan kimia) menyebabkan batu ini mudah membentuk rongga dibawah tanah (subpermukaan).

Di semenanjung Malaysia seperti di Ipoh,Perak sebahagian besar batuaannya terdiri daripada batu kapur dan filit. Batu kapur ini berpotensi membentuk rongga seterusnya terjadilah lubang benam akibat runtuhan tanah pada rongga ini. Sebagai contoh, kes yang berlaku baru-baru ini yang hampir meragut nyawa penduduk di kawasan tersebut (lihat keratan akhbar daripada Bernama).

Kejadian lubang benam atau turut dikenali tanah jerlus.

Masalah ini boleh diatasi sekiranya kajian geofizik dijalankan sebelum sebarang pembinaan atau pembangunan dijalankan. Kajian geofizik seperti Pengimejan Geoelektrik 2D boleh membantu mengenalpasti lokasi rongga dan kawasan yang berpotensi untuk berlakunya lubang benam atau tanah jerlus ini.

Di Geo Technology Resources, kami bersedia membantu memberi sokongan konsultasi serta melakukan penyiasatan geofizik dikawasan berisiko.

contoh lubang benam yang berlaku dijalan raya

Definition of Geology:

Geology is the study of the Earth, the materials of which it is made, the structure of those materials, and the processes acting upon them. It includes the study of organisms that have inhabited our planet. An important part of geology is the study of how Earth’s materials, structures, processes and organisms have changed over time.

credit to Google

What Does a Geologist Do?

Geologists work to understand many processes such as landslides, earthquakes, floods and volcanic eruptions. All of this processes can be hazardous to people. If geologists can prepare maps of areas that have flooded in the past they can prepare maps of areas that might be flooded in the future. These maps can be used to guide the development of communities and determine where flood protection or flood insurance is needed. 

We use earth materials every day. We use oil that is produced from wells, metals that are produced from mines, and water that has been drawn from streams or from underground. Geologists conduct studies that locate rocks that contain important metals, plan the mines that produce them and the methods used to remove the metals from the rocks. They do similar work to locate and produce oil, natural gas and ground water. 

Geologists also study of earth history. Nowadays, we are concerned about climate change, whether global warming or global cooling. Many geologists are working to understand about the past climate change and how its change across the time. The historical geology information helps geologist to understand how our current climate is changing.

A geohazard is the term for a geological state which has the potential to create widespread damage. Geohazards are geological and environmental conditions and involve long-term or short-term geological processes. Typical geohazards include tectonic issues, such as earthquakes and volcanoes, other naturally-occurring processes such as landslides and mud flows, or more human-induced matters such as drilling through an over-pressured geological zone. It’s important, then, that anyone in an industry dealing with the geological environment remains mindful of the risks and knows how to avoid them.

There are few examples of geohazards which are :

1) Earthquakes

2) Tsunamis

3) Landslides

4) Rock falls

5) Debris flows

6) Mud flows

and many others. Normally in Malaysia, we always faced with landslides problems. This type of geohazard could claim humans life like what happened at Bukit Antarabangsa and Rumah Persatuan  Anak Yatim Malaysia, Hulu Langat.

Geophysical methods are finding increasing application in the solution of environmental, engineering and groundwater problems. Whether the problem is one of environmental site characterization, detection of buried objects, remediation of contamination spills, or the acquisition of subsurface hydrogeological parameters, mapping/profiling subsurface targets such as mineral bodies, engineering rockhead, shallow archaeology, environmental contamination through to unexploded ordnance. A careful application of the methods of geophysics can provide insight into the geological, physical, and chemical structure and processes that operate within the near-surface.

Geophysical surveys should be a routine part of most site investigations and often represent the only way of achieving total ground coverage for what lies within the subsurface.

Why Use Geophysics?

1) Low Cost

Geophysical surveys offer remarkable value for money when compared to more conventional site investigation techniques. The value of the information acquired combined with the reduced cost from an optimally designed follow-up invasive investigation easily exceeds the original outlay – not to mention the reduced legal implications of failing to use all the common tools for site investigation available and missing targets.

2) Minimal/ No Surface Disturbance 

Since little or no ground penetration is required, the surface is not disturbed, which is ideal in urban areas, highways or landscaped environments.

3) Rapid Coverage 

By using geophysical survey, bigger area can be covered in one day compared to conventional method. 

4) Integrated Capability 

We own all of our survey equipment, which enables selection of the most suitable method to use on site without compromise.