<font color="orange">In the friday, Oct. 6 news conference on the MER rovers, there was <br />mentioned a linear feature in Victoria crater that may be a dike.<font color="white"><br /><br />See image below for a sharpened image. <br /><br />I visited Crater Lake several times; I use to live in the Portland area, I live <br />in the Phoenix Arizona area now.I was about 3 miles south of Cougar Washington <br />when Mt ST Helens blew, I took super 8 movie camera shots of it when it went <br />off and later gave copies to the USGS, if I was on the other side I would have <br />been covered in about 50 feet of ash.<br /><br />Keep up the honest guessing about volcanoes although I don't totally agree with you <br />on this. In the Martian environment, about 0.01 Earths air density, a volcano would be very <br />explosive. That’s what gives rockets an extra boost when it is cleared out of most of <br />the earth’s atmosphere; heated water vapor is very explosive in a 7 milllibar atmosphere.<br /> <br />The moon's craters before we brought back moon rocks were thought to be all volcanic <br />origin. On Mars I could see the reverse thing happening where we mistakenly think that <br />all the craters are made by impact, however the scientific instruments, although <br />there are some gray areas to be concerned about - should be able to help solve that <br />equation. <br /><br />Geologist like Jon Clarke could probably tell the difference today just by looking at a close-up <br />of it, like the image just provided by MRO. For instance does it have a central dome or <br />not - don't know if this applies to all volcanic craters especially the one's that <br />may have been under water.</font></font> <div class="Discussion_UserSignature"> Ron Bennett </div>