EARTH DYNAMICS | ReMi

<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: #FF0000" 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="#000000">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"> <h3 style="text-align: center; line-height: 119%"> THE ReMi SHEAR-WAVE VELOCITY METHOD</h3> <p class="MsoTitle" style="text-align: center; line-height: 119%"> <span style="line-height: 119%; text-decoration: underline"> <font size="4">Obtain site-specific NEHRP/IBC Vs30 site classification without a test boring!</font></span></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="MsoBodyText3"><span style="text-decoration: underline;"> <font face="Arial">The ReMi method is useful in determining:</font></span></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>Site-specific earthquake response</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>Liquefaction potential</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>Soil compaction</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>Subsurface geology</i></font></td></tr> </table><font face="Arial"> </blockquote> <p class="MsoNormal">The refraction microtremor (ReMi) method provides an effective and efficient means to acquire general, one-dimensional, information about large volumes of the subsurface with one setup.   The method can be used to estimate shear wave velocity profiles and provide site-specific NEHRP and IBC Vs30 soil classification data.  </p> <p class="MsoNormal"><span lang="EN">Testing is performed at the ground surface with no need for a specially cased borehole.  Also, since this method measures ambient seismic “noise” can be conducted in seismically noisy areas such as construction zones and urban environments.  The data acquisition consists of setting up a linear array of geophones and recording ambient seismic “noise”.  A shear-wave dispersion curve is derived and used to model subsurface shear-wave velocity.   The effective depth of investigation is related to the length of the geophone array.</span></p> <p class="MsoNormal"><span lang="EN">The </span>ReMi method (Louie 2001) is based on spectral analysis of surface waves (SASW) and multi-channel analysis of surface waves (MASW) as first described to the earthquake engineering community (Nazarian and Stokoe 1984).  With SASW, shear-velocity profiles are obtained from Rayleigh-wave phase velocities interpreted from the seismic waveforms.  The SASW interpretation is performed in the frequency domain and assumes that the most energetic arrivals are Rayleigh waves.  Applying a time-domain velocity analysis allows for separation of Rayleigh waves from body waves and other coherent noise.  The ReMi method transforms the time-domain velocity results into the frequency domain and combines many arrivals over a long period of time allowing for easy recognition of dispersive surface waves.</p> <p class="MsoNormal">This dispersion is displayed in p-f space where dispersion curve picks can be made.  These picks are used to model the subsurface geology and seismic velocities.  Examples of the p-f image, the dispersion curve fitting, and the shear-wave velocity model are shown in Figure 1.  The data in Figure 1 were collected in the vicinity of a down-hole survey.  Figure 2 contains a travel time graph and interval velocity profile from a down-hole study.  The shear-wave velocity model from a ReMi analysis conducted in the vicinity of the boring is included on the Interval Velocity plot.</p> </font></td> </tr> </table><font face="Arial"> </div> <p class="MsoNormal" align="center"> <img border="0" src="ReMiExample.gif" width="708" height="734"></p> <p class="MsoNormal" align="center"> </p> <p class="MsoNormal" align="center"> </p> <p class="MsoNormal" align="center"> <img border="0" src="Downhole-ReMi.gif" width="563" height="696"></p> <p class="MsoNormal" align="left">  </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>