A walk along the Chi Chi rupture

After several weeks in the office, we were glad to get out into the field again. This time, we had a little private excursion along the 1999 Chi Chi earthquake rupture. The Chi Chi earthquake occurred along the Chelungpu fault in western Taiwan in the very early morning of September 21st, 1999, and, with a magnitude of 7.3, it caused severe damage and the loss of over 2400 lives. A formidable memorial museum was created near Taichung, preserving the collapsed buildings and the disruption of the running track of the Kuangfu Junior High School.

As an alarmingly high percentage of school buildings in the area collapsed during the earthquake, Taiwan was incredibly lucky that the shaking happened during the night with the students in their safer homes. (In 2005, Pakistan students were less lucky during the 7.6 Kashmir earthquake, which happened around 9 o'clock in the morning...)

Keeping in mind, what impact the Chi Chi earthquake had on the Taiwanese population, we were nevertheless deeply impressed by the pronounced morphology of the surface rupture and the fantastic opportunity to study active tectonics.

The northern ending of the surface rupture consists of a foldscarp, which moved coseismically. This foldscarp forms a several meters high slope in the landscape. The road, which you can see on the following picture, was flat before the earthquake.

The folding in the landscape can also be traced by looking closely at these beetle nut trees, which grow right on the fold scarp. Their trunks show a knick, indicating their size when they were tilted by the growing fold.


The river Ta-An is cutting across this growing anticline. Its formerly gravel-filled riverbed now shows impressive bedrock incision of more than 15 m! This incision happened in the last 9 years only!

Further to the south, we found an inclined power pole, around which the local government has built a small park. We were wondering if laying out the park probably was less expensive than carefully taking down the pole...


During this trip, I saw my very first pineapple plantation! I did not know that pineapples are growing on small bushes with hard pointy leaves! You never stop learning.



To put it in a nutshell, this excursion was very impressive from what we saw concerning active geology, a bit scary to see nature's forces so vividly, very instructive and also fun!




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And here is the solution to our last posting: Both Janos and "the elephant man" were right, it is the tail of a pachyderm, more precisely that of a rhinoceros! I wonder why they knew this....