The pool sloshed back and forth with waves bigger than a cannonball creates. For many Southern Califorinians, this was the only sign that an earthquake was taking place.

“I saw the pool which looks cool whenever earthquakes happen and I knew an earthquake was happening,” senior Nathan Kriger said.

On July 4, 2019, a magnitude 6.4 earthquake shook Southern California and just a day later, a magnitude 7.1 earthquake rattled the same chandeliers. The first earthquake became the foreshock for the much bigger earthquake that followed, leaving many Southern Californians wondering when the next big one was going to hit.

The two earthquakes and ensuing aftershocks were on separate, smaller fault lines in the Mojave Desert and Ridgecrest area that are unrelated to the San Andreas Fault. Following the magnitude 7.1 earthquake, the desert floor was pulled apart at the fault about 10 feet wide.

“I like to think about the desert as an unpainted canvas, and the earthquake tore a big rip through the desert canvas,” Science Advisor for Risk Reduction Ken Hudnut of the U.S. Geological Survey (USGS) wrote to The Guardian.

The July 5 quake was 11 times stronger than the first. Following July 4, a swarm of aftershocks hit the region, but there was a 26 percent chance that the aftershock could be magnitude 6 or greater in the same region.

“Aftershocks have less intensity but they can have distributive effects. They can affect gas lines and water lines. You have to be ready for those as well,” Athletic Director Tim Chevalier said.

The main earthquake was along a fault line that ran from northwest to southeast direction, which pushed the power of the earthquake away from the populated areas. The second earthquake had the power equivalent of 45 nuclear bombs as California seismologist learned through monitoring the wave frequencies. From Southern California to Las Vegas, Nevada and Phoenix, Arizona, people felt the ground shaking.

“The light fixtures in the house did swing and the water in the pool was moving. It was the first earthquake the kids have ever felt so I realized how long it has been since we have had one,” resident of Westlake Village Rhonda Noell said.

The strength of the earthquake that Noell and many others of the Ventura Country felt were based on the direction of the fault. As the fault line pointed away from the populated areas in Ventura county, the power of the earthquake was very minimal compared to what it could have been. 

“If the earthquake is coming at you, your ground motions are going to be stronger … the waves are all packed together quite closely,” U.S. Geological Survey seismologist Elizabeth Cochran said to the Los Angeles Times.

Because the earthquake was facing the other direction, the waves did not hit Oak Park all at once, creating the rolling sensation versus pure shaking. Due to this motion, many said it was hard to tell that an earthquake was even occurring.

“[At the time of the second earthquake] I was laying on the couch when I said, ‘Is the ground moving?’, realizing there was another earthquake happening,” senior Maddy Barney-Gibbs said.

For student Barney-Gibbs, the earthquakes were a reminder that they live in California where earthquakes do occur. For adults, this was a wake-up call to re-check and make sure they are earthquake prepared.

“It did make me think about earthquake preparedness. We have earthquake backpacks that have food and water in them, but I feel like we could be better prepared,” Noell said.

Seismologists have been studying the recent twin earthquakes and it is believed two connected faults ruptured simultaneously which produced the initial shock. There was a 9 percent chance that the first earthquake was a foreshock and it turned out to be true on July 5. The possibility is that the first quake did not release the full tension in the fault lines that the second one would.

The “big one” has been on seismologists minds for the last 25 years. The last big earthquake, 5.0 or greater, to rock Southern California was Jan. 17, 1994, when a 6.7 earthquake did severe damage and shifted the culture of earthquake knowledge and preparedness in Southern California.

“We have earthquake backpacks that have food and water in them, but I feel like we could be better prepared. We always have a lot of water and food in the house but I feel that we could do a better job with some of the mechanical things we might need,” Noell said.

For many, like resident of Agoura Hills Julie Mohr, the double jolt caused them to check over their supply and to restock earthquake kits to make sure everyone is ready to go.

“The earthquake caused me to check what I do have and checked batteries and supplies for expiration dates,” Julie Mohr said.

According to the USGS, preparation measures can include having an earthquake backpack, keeping a pair of shoes close by for walking after a quake because there may be broken glass. Also, experts say all family members should learn how to turn off the gas manually. Medicines and eyeglasses should be included with the earthquake backpack.

According to experts from USGS, in the pamphlet about earthquake preparedness, “quake preparations can range from simple things — such as having earthquake kits and emergency plans ready — to more expensive items such as backup generators and quake insurance, and retrofitting buildings to better withstand shaking.”

Mayor of Los Angeles Eric Garcetti has taken steps as well to prepare Los Angeles County for what some refer to as “the big one,” meaning an earthquake about the magnitude of Northridge. The mobile app ShakeLA, part of Garcetti’s plan, can be downloaded by iPhone users and it will alert an early warning of 5.0 or greater magnitude earthquake headed for their direction. The US Geological Survey has a similar app that works for counties outside of Los Angeles..

“CalTech received a 48-second warning that the quake was coming,” US Geological Survey Seismologist Dr. Lucy Jones said during her press conference at CalTech after the second earthquake hit.

It is unclear whether the ShakeLA app worked in the two recent earthquakes. However, seismologists say more needs to happen to prepare Southern California and all of California for “the big one.”

“Being prepared is more than having your kit stocked, it’s more than having a hard hat under your bed,” president of the Structural Engineers Association of Southern California Ken O’Dell said. “We need to be preparing our buildings.”

Many are urging for the passage of a bill, Assembly Bill 1857, that was vetoed by former Governor of California Jerry Brown. This bill would make the building code stricter and allow buildings to be used after an earthquake. While some buildings in Los Angeles and San Francisco have been retrofitted, more need to be prepared.

More than a million homes were vulnerable during the two earthquakes. This is due to the fact that without retrofitting, homes are not considered resilient and will not withstand the shaking caused by an earthquake. Retrofitting is done to homes built prior to 1979 where there are steps in front because that means there is space between the floor of the house and the concrete slab house causing the house to fall in. These causes are called single family homes and are all over California. Retrofitting can cost the city and homeowners some money, but the bill is considerably smaller than it would be when the damage occurs after an earthquake.

“If a financial district is obliterated by the collapse of a single steel skyscraper, who is going to want to go into all the other ones that didn’t collapse? Our trust in those buildings will evaporate,” nationally renowned earthquake engineer and research professor at the University of Colorado Boulder Keith Porter said.

While Ridgecrest and Trona did have damage, it was very limited to interior structural damage and a couple of fires due to gas lines that caused damage. There were no deaths. Both felt either level 6 or level 7 shaking, which are both classified as “strong.” However, if an earthquake with the power of the Northridge earthquake of 1994 were to hit, it would be considered a level 8, which is severe. Level 8 shaking in the middle of the city with a concentrated population can cause millions of dollars worth of damage. However, it can be difficult to forsee what another earthquake may spell out for Southern California.

“The bottom line is we don’t ever have a crystal ball,” USGS seismologist Susan Hough said. “The next earthquake may be something that no one sees is coming.”

The government and seismologists have released a checklist for kits and what to do during an earthquake. Experts suggest that within the next few months people should prepare to make sure they have what is needed in case of such an emergency.

Since July 4, 2019, more than 80 thousand aftershocks have hit and it is currently unknown when one will be bigger than a 4.0 magnitude.

“I think the more frequent these earthquakes happen, the more nervous we are for one on a much larger scale,” Mohr said.