A steady stream of news reports around the world are causing concern: a deadly volcanic explosion in Italy, a raised volcanic alert in Hawaii, two of the strongest earthquakes in 20 years to strike California, and numerous quakes shaking and volcanoes perking up to life around the Ring of Fire in the Pacific. While it seems that the Earth has been unusually angry the last few days, everything is normal according to leading geologists. And even though things are normal, people in California and Hawaii should be getting ready for the “Big One.”
In Hawaii, the “Big One” there is considered to be the eruption of Mauna Loa. Mauna Loa is the largest, by volume, of the five volcanoes that form Hawaii’s Big Island. Known as the largest subaerial volcano in the world in both mass and volume, the active shield volcano has barren gentle slopes that rise up to 13,679 feet. Most of the volcano sits below the ocean, with another 16,400 feet to the sea floor. The 30,085 foot elevation from base to summit is greater than the 29,029 foot elevation of Mount Everest from sea level to summit. And it’s overdue for an eruption.
According to the USGS and the Hawaiian Volcano Observatory (HVO) located on Hawaii’s Big Island, Mauna Loa is a rather active volcano. According to them, during the past 3,000 years, Mauna Loa has erupted lava flows, on average, every 6 years. Since 1843, Mauna Loa has erupted 33 times, averaging one eruption every 5 years. However, the last eruption was in March/April of 1983. The volcano has been quiet for more than 35 years, leading some to say it’s “long overdue” for an eruption.
Recently, Mauna Loa has showed some increasing signs of life. For the past several months, earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. The USGS is careful to tell people that an eruption is not imminent and current rates are not cause for alarm. However, they do indicate changes in the shallow magma storage system at Mauna Loa.
Following a significant earthquake swarm in October 2018, HVO seismic stations have recorded an average of at least 50 shallow, small-magnitude earthquakes per week beneath Mauna Loa’s summit, upper Southwest Rift Zone, and upper west flank. This compares to a rate of fewer than 20 per week in the first half of 2018. Shallow earthquakes are occurring in locations similar to those that preceded Mauna Loa’s most recent eruptions in 1975 and 1984. During this same time period, GPS instrumentation and satellite radar have measured ground deformation consistent with renewed recharge of the volcano’s shallow magma storage system. The current rate and pattern of ground deformation is similar to that measured during inflation of Mauna Loa in 2005 and again from 2014 – 2018.
Based on those observations, scientists raised the alert level at the volcano on July 2, cautioning that an eruption may occur sometime in the not-so-distant future. As such, HVO elevated the Mauna Loa alert level to “advisory” and the aviation color code to YELLOW. Should instruments show an eruption is more likely to occur, the advisory and aviation color would rise once again. It is likely people in Hawaii would have at least many hours, if not days, advance notice that the volcano is due to erupt.
Mauna Loa is many times larger than Kilauea, which had an eruption last year in its Lower East Rift Zone. Should Mauna Loa erupt, a large part of the island could be vulnerable from lava inundation, including portions of the metro Kona and Hilo areas.
Meanwhile, California is getting ready for it’s own “Big One.” Rather than a volcano, the big one there refers to a large magnitude earthquake likely to strike southern California. July 4th’s significant 6.4 earthquake followed by last night’s even stronger 7.1 has California’s on edge, wondering if the “Big One” will strike soon.
Paul Caruso, a geophysicist with the U.S. Geological Survey in Golden, Colorado, said Thursday’s earthquake did not change the agency’s calculations of when the big one might strike. “We are not changing our forecast for the San Andreas,” Caruso said. “We still believe there’s a 70% chance of a magnitude 7 or greater in Southern California before 2030.” The San Andreas fault, which runs near heavily populated areas and defines the boundary between the North American and Pacific tectonic plates, is considered the biggest seismic threat to California. Related faults in the Earth, like the Hayward fault that runs through Oakland and Berkeley in the San Francisco Bay Area in northern California, are also considered major threats.
As with the Hawaiian volcanoes, large earthquakes do occur with regularity over California, but over the last few decades, things have been remarkably quiet. That will change, scientists warn, although no one is exactly sure when exactly that’ll happen.
With the lethal eruption of Stromboli in Italy and a large number of earthquakes and volcanoes rocking across the Pacific, some are concerned the Big Ones in Hawaii and California will happen very soon. However, geologists say there’s no link between these events and people should not be alarmed.
Renowned volcano expert, Dr. Janine Krippner, tells us people shouldn’t draw conclusions about the earthquakes and volcanoes that are happening around the world and assume they’re a precursor to a big event in your backyard. “These are completely different events in completely different tectonic settings, divided by huge distances,” she tells us. “It might be tempting to connect eruptions & earthquakes but these events occur around the globe all the time largely unnoticed by most. More in the news does not mean more.”
On Hawaii’s Big Island, @CivilDefenseHI hosted a Disaster Preparedness Fair, w/dozens of local/federal officials on-hand to offer tips & advice. W/the possible threat from a tropical cyclone in the extended forecast range, NOW is the time to prepare. #HIwx https://t.co/l6Ou5103sB pic.twitter.com/ysEcC7zxtJ
— the Weatherboy (@theWeatherboy) June 30, 2019
While more in the news doesn’t mean more will form, it is important to be prepared for the next disaster. On Hawaii’s Big Island, Civil Defense recently held a Disaster Preparedness Fair to prepare residents there for the next volcanic eruption, earthquake, or hurricane that could impact there. In California, officials there are encouraging people to review their disaster plans; FEMA is recommending that people visit the ShakeOut website for more tips on what to do before, during, and after an earthquake.
Scientists aren’t sure when these disasters will strike. But they are certain they will.