It’s Flooding down in Texas
San Antonio had the 2nd highest daily rainfall total on Saturday May 25, 2013. Although the property damage and loss of life are unfortunate consequences of this heavy deluge, Texas could always use water. The past few years have been pretty dry. However this water will go a long way in recharging the Edwards Aquifer.
Stevie Ray knew about floods in Texas, with his famous – It’s Flooding down in Texas from Texas Flood, but he may have not known about this interesting (to me anyway), happening back in 1964.
Edwards Aquifer
On March 27, 1964, there was a very strong earthquake in Alaska, a 9.2 magnitude on the Richter scale. This quake was the strongest ever recorded in North America and occurred near Anchorage at 5:36 pm local time. This quake was so strong that the seismic waves that radiated out from the quake reached Texas, and the substrata below San Antonio in about 9 minutes. This is an incredible speed of more than 21,000 mph. (The P wave from an earthquake can travel up to 13 km/sec.)
Hydrologists have been monitoring the water levels in the Edwards Aquifer for a long time and have been recording data from strategically located test wells all across the Aquifer. There is a test and monitoring well near the national cemetery at Fort Sam Houston in San Antonio, simply numbered “J-17”. J-17 is on a major Edwards Aquifer flow stream and it responds quickly to changes in usage and recharge. J-17 has been an important gauge since the mid 50’s, for the storage levels in the Edwards Aquifer in the San Antonio area.
At 9:45 pm in San Antonio, the J-17 well had a water level of 76.8 feet below the surface. Immediately as the shock wave hit, the recording chart pen dropped completely off the bottom of the chart at 79 feet. Next it rose so fast that it skipped a section of the chart. As a result the pen left faint mark where it ran off the top of the chart at 74 feet. This powerful quake in Alaska generated shock waves. The Aquifer responded with a pulse of over five feet in J-17.
Here is the chart printed in the San Antonio Express in May of 1964.
