 Damage produced by the 8.4 in Evansville. | |
| Date | July 23, 2018 |
| Time | 4:26PM EDT (first quake)
5:41PM EDT (second quake) |
| Type | Dip-slip |
| Duration | 31 seconds (first quake)
2 minutes, 18 seconds (second quake) |
| Magnitude | 6.1 (first quake)
8.4 (second quake) |
| Epicenter | 1 N of Santa Claus, IN (first quake)
6 NE of Evansville, IN (second quake) |
| Depth | 14 miles (first quake)
21 miles (second quake) |
| Shaking intensity | VIII. Severe (first quake)
XII. Extreme (second quake) |
| Foreshocks | 1 (First quake) |
| Aftershocks | 426 |
| Tsunami | None |
| Damages | $131B (2018 USD) (Costliest natural disaster in history) |
| Fatalities | 86 (first quake)
314 (second quake) |
| Areas affected | Midwestern United States, Southeastern United States, Ontario |
the 2018 Wabash Valley Seismic Zone earthquake (also known as the 2018 Indiana earthquakes) were two powerful earthquakes which occurred about a hour apart on July 23, 2018. The two earthquakes were a magnitude 6.1 and 8.4, respectively. However, damage in the 6.1 earthquake resembled 8.0 damage in a more earthquake-prepared area and the 8.4 earthquake produced 9.0 like damage. These earthquakes were the worst in the Wabash Seismic Zone's history, and the 8.4 is the strongest earthquake ever produced in the Midwestern United States.
Santa Claus earthquake (Earthquake #1)[]
At 4:26PM, slight shaking began at Holiday World park in Santa Claus, Indiana...within a few seconds "unbelievable" shaking in a Indiana earthquake was in progress as wave pools shook so much that people were dragged under and water slides collapsed. At total of 26 people died at Holiday World alone, with a additional 60 dying across Spencer County. The governor declared a state of emergency less than 45 minutes after the first earthquake (or about 45 minutes until the second one). The earthquake was later on confirmed to be a Magnitude 6.1 with a shaking intensity of VIII (Severe). It was confirmed that the earthquake was a major dip-slip quake. The earthquake for about a hour and 20 minutes held the record as the strongest earthquake with a epi-center in Indiana. It was reported that this earthquake wasn't even related to the Wabash Valley Seismic Zone but that it did provide as a foreshock to the 8.4.
Evansville earthquake (Earthquake #2)[]
At 5:29PM, all of Indiana and Kentucky were put under a Earthquake Watch due to the potential of a major earthquake occurring shortly. Shortly later at 5:39PM, it was upgraded to a Earthquake Warning for southwestern Indiana. Just two minutes later, moderate shaking began in Evansville as a earthquake with a epicenter about 6 miles northeast of Evansville began. About 20 seconds into the quake the shaking was equal to that of the first quake and by a minute in it was at XII status. Pure devastation was recorded as most structures in Evansville and surrounding areas collapsed. Mass casualties were confirmed and the earthquake was confirmed to be a 8.4 the next morning when the USGS did a full investigation on the two earthquakes. In total the two earthquakes produced over $130 billion in damages, making them the costliest natural disasters in history. It is unknown why a normally inactive seismic zone that produces a few weak earthquakes every few years suddenly produced 2 very violent earthquakes just a hour apart.