Magnitude 4.Earthquake Strikes Pahala, Hawaii, Near Mauna Loa Volcano

More than 100 people reported feeling an earthquake near the world's largest volcano, according to the USGS. A magnitude 4.0 earthquake happened at Pahala, Hawaii, near the Mauna Loa volcano, at 7:11 p.m. local time / 1:11 a.m. ET.

Light shaking was recorded by 111 persons in the first hour following the earthquake using the USGS's "Did you feel it? "An online reporting tool for the Big Island of Hawaii."

The shaking of Mauna Loa

(Photo : Raph Howald/Unsplash)

Mauna Loa is the world's largest active volcano, rising 13,681 feet above sea level. Mauna Loa rises from the Central Pacific Ocean floor at a depth of roughly 3 miles, as per Weatherboy.

The ocean floor just beneath Mauna Loa is depressed by additional 5 miles due to the volcano's mass.

According to the USGS, this places Mauna Loa's summit around 56,000 feet above its base; the massive volcano encompasses half of Hawaii, sometimes known simply as the Big Island of Hawaii.

Mauna Loa eruptions typically result in large, fast-moving lava flows that can affect settlements on the Big Island's east and west flanks, from Kona to Hilo.

Many scientists assumed that lava flows beneath Pahala are on their way to Mauna Loa and Kilauea volcanoes, which have been erupting for months.

Fortunately, the depth and location of this earthquake are consistent with the heightened deep activity surrounding Pahala since 2019 and do not suggest a major eruption at either volcano.

According to the USGS, these types of earthquakes normally have no effect on ongoing activity on Mauna Loa or Kilauea.

Nonetheless, scientists are keeping a careful eye on both volcanoes for any changes in behavior.

While Mauna Loa is not now erupting, rates of deformation and seismicity remain elevated beyond long-term background values, according to the USGS.

GPS readings suggest moderate, long-term summit inflation, which is compatible with magma delivery to the volcano's shallow storage system.

Also Read: Largest Underwater Eruption Gives Rise to a Massive Volcano, Prompting Researchers to Mount Expedition

Volcano watch

Recently, scientists at the USGS Hawaiian Volcano Observatory (HVO) were kept awake late on August 2 and early on August 3 monitoring Mauna Loa.

Over the course of nearly ten hours, 90 earthquakes were identified beneath Mauna Loa's summit region, and many more were reported but were too tiny to pinpoint.

The overall number of earthquakes each hour reached above 200.

During the swarm, HVO scientists were evaluating the incoming data on the fly and attempting to answer queries like, "Where are the earthquakes happening? Is there a shift in activity? Are other monitoring datasets changing?"

The earthquakes occurred about 2 miles (3 km) beneath the top of Mauna Loa's summit, and their locations did not migrate horizontally or vertically over time to another region or depth.

The fact that the earthquakes did not get shallower was a reassuring sign that the swarm was not caused by magma rapidly climbing into an explosion.

An earthquake swarm in and of itself is not unusual-swarms have occurred beneath Mauna Loa's summit in the past.

During the Spring of 2021, an earthquake swarm beneath Mauna Loa's summit produced around a thousand earthquakes during a seven-week period, with a peak rate of 40 earthquakes per day.

The shift in another monitoring dataset was another one-of-a-kind incident.

During the August 2 to 3 earthquakes, a tiltmeter on the north side of Moku'weoweo-Mauna Loa's summit caldera-showed a movement of roughly 1.5 microradians.

Tiltmeters are devices that measure changes in ground slope.

Although minor and partly disguised by daily swings caused by temperature changes, the change connected with the earthquake swarm shows a tiny expansion or inflation of Mauna Loa.

Lava has continued to erupt from the western vent within the Halemaumau crater throughout the last week.

The whole lava flow is contained within the Halemaumau crater in Hawai'i Volcanoes National Park.

Sulfur dioxide emissions continue to be high, with the most recent measurement being around 2,200 tonnes per day (t/d) on August 10.

With few earthquakes and continuous volcanic tremors, seismicity is elevated but stable.

Summit tiltmeters reported one deflation-inflation sequence throughout the last week (DI-event).

Mauna Loa is not erupting and remains at Volcano Alert Level ADVISORY, which does not imply that an eruption is imminent or that the current level of unrest will lead to an eruption

Weekly Mauna Loa updates are provided.