EARTH DYNAMICS | EM

<body onload="dynAnimation()" background="_themes/earthdyn2/stonbk.jpg" bgcolor="#FFFFFF" text="#000000" link="#003399" vlink="#800000" alink="#666666"><font face="Arial"> <p align="left" style="margin-top: -10; margin-bottom: 0"> <img border="0" src="_borders/logo3.jpg" align="left" width="66" height="87"><font size="7" color="#0000FF"><b><i> </i></b></font><b><i><font size="7" color="#0000FF">EARTH DYNAMICS</font></i></b></p> </font><table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse; float:right; position:absolute; left:734; top:-2" width="334" height="93" align="right"> <tr> <td width="334" height="68" valign="top"><font face="Arial"> <p style="margin-bottom: -15" align="center"><b><font color="#0000FF">Providing Consulting Services To</font></b></p> <p align="center"> <b> <font color="#0000FF">The Pacific Northwest Since 1984</font></b></p> <p align="center"> <b>503-227-7659</b></p> </font></td> </tr> </table><font face="Arial"> <blockquote> <p style="margin-top: -15; margin-bottom: 0" align="left"> <b> <font size="4" color="#0000FF">  </font>       Geophysics ● Vibration & Noise ● Rock Mechanics</b></p> </blockquote> <p> </p> <p align="center"> <script language="JavaScript"></script><script language="JavaScript"></script><a href="index.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav1'].src=MSFPnav1h.src" onmouseout="if(MSFPhover) document['MSFPnav1'].src=MSFPnav1n.src" target="_top"><img src="_derived/home_cmp_ed-mainpage010_hbtn.gif" width="144" height="46" border="0" alt="Home" align="middle" name="MSFPnav1"></a> <script language="JavaScript"></script><a href="Geophysical_Methods.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav2'].src=MSFPnav2h.src" onmouseout="if(MSFPhover) document['MSFPnav2'].src=MSFPnav2n.src" target="_top"><img src="_derived/Geophysical_Methods.htm_cmp_ed-methods-link010_hbtn.gif" width="144" height="46" border="0" alt="Geophysical Methods" align="middle" name="MSFPnav2"></a> <script language="JavaScript"></script><a href="Vibration_&_Acoustic.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav3'].src=MSFPnav3h.src" onmouseout="if(MSFPhover) document['MSFPnav3'].src=MSFPnav3n.src" target="_top"><img src="_derived/Vibration_&_Acoustic.htm_cmp_ed-mainpage010_hbtn.gif" width="144" height="46" border="0" alt="Vibration & Acoustic" align="middle" name="MSFPnav3"></a> <script language="JavaScript"></script><a href="Rock_Mechanics.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav4'].src=MSFPnav4h.src" onmouseout="if(MSFPhover) document['MSFPnav4'].src=MSFPnav4n.src" target="_top"><img src="_derived/Rock_Mechanics.htm_cmp_ed-mainpage010_hbtn.gif" width="144" height="46" border="0" alt="Rock Mechanics" align="middle" name="MSFPnav4"></a> <script language="JavaScript"></script><a href="Applications.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav5'].src=MSFPnav5h.src" onmouseout="if(MSFPhover) document['MSFPnav5'].src=MSFPnav5n.src" target="_top"><img src="_derived/Applications.htm_cmp_ed-mainpage010_hbtn.gif" width="144" height="46" border="0" alt="Applications" align="middle" name="MSFPnav5"></a></p> <p align="center"><img src="_themes/earthdyn2/hline.gif" width="600" height="10"></p></font><table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" width="100%"> <tr> <td width="123" height="330" valign="top"><font face="Arial"> <h5 align="left"> <font style="font-size: 9pt"> <a style="font-family: Arial; font-weight:400" dynamicanimation="fpAnimformatRolloverFP1" fprolloverstyle="color: #0000FF" onmouseover="rollIn(this)" onmouseout="rollOut(this)" language="Javascript1.2" href="Ground_Penetrating_Radar.htm"> <font color="#000000">GPR</font></a></font></h5> <p><font style="font-size: 9pt"> <a style="font-family: Arial; color: #000000" target="_top" href="Electrical_Resistivity.htm">Electrical Resistivity</a></font></p> <p><font style="font-size: 9pt"> <a style="color: #000000" href="Seismic_Refraction.htm">Seismic Refraction</a></font></p> <p><font style="font-size: 9pt"> <a style="color: #000000" href="ReMi_Shear_Wave.htm">ReMi<br>Shear Wave</a></font></p> <p><font style="font-size: 9pt"> <a style="color: #000000" href="Magnetics.htm">Magnetics</a></font></p> <p><a href="Electromagnetics.htm"><font style="font-size: 9pt" color="#FF0000">Electromagnetics</font></a></p> <p><a href="Gravity.htm"><font style="font-size: 9pt" color="#000000">Gravity</font></a></p> <p><font style="font-size: 9pt" color="#000000"> <a href="Downhole_Seismic.htm"> <font color="#000000">Downhole Seismic</font></a></font></p> <p><font color="#000000"><span style="font-size: 9pt"> <a href="Crosshole_Sonic_Logging.htm"><font color="#000000">CSL</font></a></span></font></p> <p><a href="Marine_Geophysics.htm"><font color="#000000" style="font-size: 9pt"> Marine<br>Geophysics</font></a></p> </font></td> <td width="902" height="330" valign="top"><font face="Arial"> <p align="center"><b><font size="4">ELECTROMAGNETIC </font></b><font size="4"> <b>METHODS</b></font></p> <div align="left"> </font><table border="0" cellpadding="0" cellspacing="0" style="border-collapse: collapse" width="98%"> <tr> <td width="100%"><font face="Arial"> <p class="MsoNormal">An Electromagnetic survey is useful for locating buried ferrous and non-ferrous material.   The Electromagnetic Methods are:</p> <blockquote> </font><table border="0" cellpadding="0" cellspacing="0" width="100%"> <tr><td valign="top" width="42"><img src="_themes/earthdyn2/abstrbu2.gif" width="12" height="12" hspace="15" alt="bullet"></td><td valign="top" width="100%"><font face="Arial"><i>Cost effective.  Large sites are surveyed quickly and easily.</i></font></td></tr> <tr><td valign="baseline" width="42"><img src="_themes/earthdyn2/abstrbu2.gif" width="12" height="12" hspace="15" alt="bullet"></td><td valign="top" width="100%"><font face="Arial"><i>Non-destructive and non-invasive</i></font></td></tr> <tr><td valign="baseline" width="42"><img src="_themes/earthdyn2/abstrbu2.gif" width="12" height="12" hspace="15" alt="bullet"></td><td valign="top" width="100%"><font face="Arial"><i>Extremely portable and environmentally neutral</i></font></td></tr> <tr><td valign="baseline" width="42"><img src="_themes/earthdyn2/abstrbu2.gif" width="12" height="12" hspace="15" alt="bullet"></td><td valign="top" width="100%"><font face="Arial"><i>On site real-time data allows for preliminary anomaly identification</i></font></td></tr> </table><font face="Arial"> </blockquote> <p class="MsoNormal">Electromagnetic (EM) induction uses a transmitter to generate a pulsed primary magnetic field.  The transmitted magnetic field induces eddy currents in nearby ferrous and non-ferrous metallic objects.   The EM measuring device senses the eddy current fields.  The amplitude and phase of the eddy current fields are related to the electrical properties of the subsurface.<img border="2" src="EM61Photo.jpg" align="right" width="288" height="216"></p> <p class="body-txt">There are two types of Electromagnetic Induction  techniques commonly used. These are time-domain and frequency-domain.<br> <br> <i><b>Time Domain Electromagnetic Induction</b></i><br><span class="body-txt">The time-domain instrument produces a short low energy electromagnetic pulse from the transmitter coil. A receiver coil measures the decaying signal induced into the ground with respect to time.</span></p> <p class="body-txt"><span class="body-txt"> On completion of each survey the dataset is downloaded to a computer for processing.  The data are used to produce site maps showing the locations and sizes of detected anomalies.</span></p> <p class="body-txt"><span class="body-txt">The time domain method allows very sensitive detection of shallow and deep buried metal objects  It </span>is capable of detecting and mapping the location of both ferrous and non-ferrous buried metallic objects, large or small.  For example, it is capable of detecting a buried 55 gallon drum at a depth of 3m.</p> <p class="body-txt"><i><b>Frequency Domain Electromagnetic Induction</b></i><br>The frequency domain instrument normally operates at a fixed frequency. The generated signal creates small subsurface eddy currents beneath the instrument. Automatic accurate measurements of the components of the generated subsurface eddy currents are then used to record changes in the subsurface soil conditions.</p> <p class="body-txt">The frequency domain method is capable of detecting and mapping any contaminant plume that is causing even a small change in soil conductivity/resistivity. It can be used to find buried dumpsites, leachate plumes, voids, underground streams and aquifers and buried metallic/magnetic objects.<br>  </p> </font></td> </tr> </table><font face="Arial"> </div> <p class="body-txt" align="center"><img border="0" src="EMData.gif" width="681" height="360"></p> <p class="body-txt" align="center"><b>Example of Electromagnetics Data</b></p> <p> </font></td> </tr> </table><font face="Arial"><p align="center"><img src="_themes/earthdyn2/hline.gif" width="600" height="10"></p> <p align="center" style="margin-bottom: -17; "> <script language="JavaScript"></script><a href="index.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav6'].src=MSFPnav6h.src" onmouseout="if(MSFPhover) document['MSFPnav6'].src=MSFPnav6n.src" target="_top"><img src="_derived/home_cmp_ed-global-010_hbtn.gif" width="95" height="20" border="0" alt="Home" align="middle" name="MSFPnav6"></a> <script language="JavaScript"></script><a href="Key_Personnel.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav7'].src=MSFPnav7h.src" onmouseout="if(MSFPhover) document['MSFPnav7'].src=MSFPnav7n.src" target="_top"><img src="_derived/Key_Personnel.htm_cmp_ed-global-010_hbtn.gif" width="95" height="20" border="0" alt="Personnel" align="middle" name="MSFPnav7"></a> <script language="JavaScript"></script><a href="Client_List.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav8'].src=MSFPnav8h.src" onmouseout="if(MSFPhover) document['MSFPnav8'].src=MSFPnav8n.src" target="_top"><img src="_derived/Client_List.htm_cmp_ed-global-010_hbtn.gif" width="95" height="20" border="0" alt="Client List" align="middle" name="MSFPnav8"></a> <script language="JavaScript"></script><a href="News.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav9'].src=MSFPnav9h.src" onmouseout="if(MSFPhover) document['MSFPnav9'].src=MSFPnav9n.src" target="_top"><img src="_derived/News.htm_cmp_ed-global-010_hbtn.gif" width="95" height="20" border="0" alt="News" align="middle" name="MSFPnav9"></a> <script language="JavaScript"></script><a href="Site_Map.htm" language="JavaScript" onmouseover="if(MSFPhover) document['MSFPnav10'].src=MSFPnav10h.src" onmouseout="if(MSFPhover) document['MSFPnav10'].src=MSFPnav10n.src" target="_top"><img src="_derived/Site_Map.htm_cmp_ed-global-010_hbtn.gif" width="95" height="20" border="0" alt="Site Map" align="middle" name="MSFPnav10"></a></p> <p align="center" style="margin-bottom: -17; ">  </p> <p align="center" style="margin-bottom: -17; "> <u><b><i>Contact Information</i></b><i><b><font size="2"><br> </font></b></i></u><font size="2">2284 NW Thurman Street, Portland, Oregon  97210</font></p> <p align="center" style="margin-bottom: -17; margin-top:15"> <font size="2">voice: (503) 227-7659  fax: (503) 227-1074</font></p> <p align="center" style="margin-bottom: -17; margin-top:15">  </p> <p align="center" style="margin-top: 10"> <font size="1">Last modified: March 07, 2008</font></p> </font></body>