There are instances in which comments or results of analysis for two or 

 more activities are similar. These repetitive portions could have been 

 edited, instructing the reader to jump to other places in the chapter for more 

 information. Since the purpose of the technical report was to provide a 

 reference source for the land manager, and "cover-to-cover" reading of the 

 chapter by the user was not anticipated, the repeated portions are included 

 for completeness and ease of use. 



Coastal Uplands 



Seismic preexploration. 



1. Activity Sequence 



Seismic crews enter by truck, survey the site, and hand-clear a 

 precise alignment through the vegetation for the placement of geo- 

 phones and shot charges. A bulldozer may clear dense vegetation. 

 The crew drills shot holes, lays connecting and sensor cables, and 

 monitors the test. Following testing, shot tubes are retrieved, 

 shot holes plugged with earth, and the crew either advances to the 

 next series of stations or leaves the area. Preexploration ceases 

 with vehicle exit. 



2. Primary ecological alterations 



2.1 Localized crushing and trampling of vegetation by survey and 

 seismic vehicles 



2.2 Creation of unvegetated shot lanes 3 to 4 m (10 to 13 ft) wide 

 and hundreds of meters long 



2.3 Localized loss of soil structure due to compaction caused by 

 vehicular activity 



2.4 Short-term displacement of sensitive wildlife species due to 

 noise and human activity 



3. Attribute alterations 



The abiotic and biotic effects of seismic activity are very local- 

 ized, quantitatively small, and of minor consequence at the ecosystem 

 lev?! of consideration, although specific site alterations may cause 

 more significant disruptions at the community level. Important 

 community differences are noted below (sections 3.1 to 3.3). 



149 



