Massive 7.4 magnitude earthquake hits US; tsunami warning issued

A powerful earthquake of magnitude 7.4 struck the Alaska Peninsula region in the United States on Sunday, triggering a tsunami threat for parts of the coast. The quake was felt across the state and was followed by several aftershocks, some of them strong as well.

What happened?

According to the United States Geological Survey (USGS), the earthquake occurred at 12:46 pm local time (10:16 pm IST) at a depth of 9.3 km (5.78 miles), about 106 km (66 miles) south of Sand Point, a town of about 900 people off the Alaska Peninsula. The quake was initially reported as magnitude 7.5, but later downgraded to 7.4 by USGS.

The earthquake was the result of a thrust faulting on or near the subduction zone interface between the Pacific and North America plates, where the Pacific plate moves northwestward with respect to North America at a rate of about 59 mm/yr.

The U.S. Tsunami Warning System issued a tsunami warning for South Alaska and the Alaska Peninsula, from Kennedy Entrance, 40 miles southwest of Homer, to Unimak Pass, 80 miles northeast of Unalaska. The warning was later cancelled after no significant waves were observed.

What are the impacts?

The earthquake was widely felt across Alaska, with reports of shaking coming from as far as Anchorage, about 575 miles (925 km) away from the epicenter. Some residents in coastal areas evacuated to higher ground following the tsunami warning.

There were no immediate reports of injuries or major damage from the quake. However, some power outages and minor structural damage were reported in some communities.

The Alaska Earthquake Center said that more than a dozen aftershocks were recorded after the main quake, ranging from magnitude 3.5 to 5.9. The center warned that more aftershocks are expected and some of them may be felt.

What is the significance?

The earthquake was one of the strongest to hit Alaska in recent years. In 2018, a magnitude 7.1 quake struck near Anchorage, causing widespread damage and injuring dozens of people.

Alaska is one of the most seismically active regions in the world, due to its location along the Pacific Ring of Fire, a belt of volcanoes and fault lines encircling the Pacific Ocean. The state experiences thousands of earthquakes every year, most of them small and harmless.

However, some of them can be devastating, such as the magnitude 9.2 quake that struck in 1964, which was the second-largest ever recorded and killed more than 130 people.

What are the implications?

The earthquake serves as a reminder of the potential hazards posed by seismic activity in Alaska and other parts of the world. It also highlights the importance of preparedness and resilience in coping with such events.

The U.S. Tsunami Warning System provides timely and accurate information on tsunami threats and advises people on what actions to take in case of an emergency. The system is part of a global network of tsunami warning centers that monitor seismic and sea level data around the world.

People living in coastal areas should be aware of the signs of a possible tsunami, such as strong shaking, unusual sea level changes, or loud roaring sounds from the ocean. They should also know how to evacuate to safe locations and follow the instructions from local authorities.

The earthquake also underscores the need for further research and monitoring of seismic activity and its effects on human and natural systems. Scientists are constantly working to improve their understanding of earthquake mechanisms, hazards, and risks, as well as to develop better methods for forecasting, mitigation, and response.

Source: 

(1) Magnitude 7.4 earthquake strikes U.S. Alaska, tsunami warning issued. https://www.thehindu.com/news/international/magnitude-74-earthquake-strikes-us-alaska-tsunami-warning-issued/article67086651.ece.

(2) Massive 7.4 magnitude earthquake hits US; tsunami warning issued. https://inshorts.com/en/news/massive-74-magnitude-earthquake-hits-us-tsunami-warning-issued-1689492591862.

(3) Tsunami Warnings Issued for Parts of Alaska After 7.4 Magnitude Earthquake. https://www.newsweek.com/tsunami-warnings-issued-parts-alaska-after-74-magnitude-earthquake-1540420.

(4) United States: Earthquake Of 7.4 Magnitude Hits Alaska Peninsula Region .... https://www.outlookindia.com/international/earthquake-of-7-4-magnitude-hits-us-alaska-tsunami-warning-issued-news-303259.

(5) 7.4-magnitude earthquake strikes Alaska, tsunami alert issued. https://www.businesstoday.in/latest/story/74-magnitude-earthquake-strikes-alaska-tsunami-alert-issued-389906-2023-07-16.