US Geological Survey done at the time, with photos and eyewitness accounts: <a href="http:&#x2F;&#x2F;pubs.usgs.gov&#x2F;pp&#x2F;0354c&#x2F;report.pdf" rel="nofollow">http:&#x2F;&#x2F;pubs.usgs.gov&#x2F;pp&#x2F;0354c&#x2F;report.pdf</a>