"It Expands Violently..."

 
 
While I was traipsing about the hills, photographing the culverts for my article on Anaheim's Landslide-Prone Infrastructure, I noticed a stone-like structure that was obviously a direct cause to some of the most-severe damage to the concrete culverts.  These structures seemed to actually be growing straight up out of the ground.  And the observable growth, as shown in the following photographs, is quite rapid -- well over a foot in five years.

The next day I returned to the site with hammer and chisel in hand and then carted off thirty-some pounds of rocks.  On Tuesday, I brought my find to the renowned Doctor Peter Borella, who, in addition to having a Ph.D.. in Geology, has a thorough working knowledge of the geological history of Orange County.

After determining exactly where these rocks originated from, Dr. Borella then identified them as part of the Puente Formation - Yorba Member, Paleocene Age and that they were "diatomaceous siltstone formations."

I asked him: "What is the difference between diatomaceous siltstone and diatomaceous siltstone?"

Dr. Borella responded:  "While siltstone tends to be expansive when it becomes wet; diatomaceous siltstone expands violently!"

This violent expansion is how it destroys streets, sidewalks and the foundations of any homes in its path.

 
Diatomaceous siltstone photographs taken on October 10, 1998

Culvert being destroyed by diatomaceous siltstone -- View #1.
Diatomaceous siltstone growing upward -- View #2.
Diatomaceous siltstone growing upward -- View #3.
Diatomaceous siltstone growing upward -- View #4.
Diatomaceous siltstone growing upward -- View #5.
Diatomaceous siltstone growing upward -- View #6.
Diatomaceous siltstone growing upward -- View #7.
Diatomaceous siltstone growing upward -- View #8.
Diatomaceous siltstone growing upward -- View #9.
Diatomaceous siltstone growing upward -- View #10.
Diatomaceous siltstone growing upward -- View #11.
Diatomaceous siltstone growing upward -- View #12.
Diatomaceous siltstone growing upward -- View #13.
 

Landslide