Great Alaskan earthquake
It occurred on March 27, 1964. The first underground shock with a magnitude of 9.2 on the Richter scale was recorded at 3:36 a.m., its epicenter was located deep in Collegiate Fjord in Prince William Sound on the west coast of North America. This is a zone of high seismic activity, as the North American and Pacific plates are in subduction, i.e., moving under each other.
The tremors, which lasted four minutes, seriously changed the entire geology of the region. Latush Island moved 18 meters to the south, and Kadyak Island rose out of the water by 15 meters. The city of Anchorage, located 120 kilometers from the epicenter, was severely damaged, especially its suburb of Turnagain Heights, where a huge landslide buried 75 houses. The city of Portage was completely destroyed, dropping 3 meters below sea level. The town of Valdiz was also completely destroyed. The area affected by the earthquake was approximately 130,000 square kilometers, but due to the low population density in these places, only 9 people died.
Earthquake in Hawaii
In the first week of May 2018, more than 70 aftershocks were recorded, with a minimum amplitude of 2.5 on the Richter scale (earthquake magnitude) and a maximum amplitude of more than 7, which led to the closure and evacuation of the National Park, covering 140,000 hectares – 13 percent of the total area of the Big Island. As of May 4, 2018, there were no reports of injuries or deaths, however, 2 residential buildings were caught in the lava ring, and the population was warned about the presence of hazardous gases in the air. The evacuation, in one way or another, affected about ten thousand citizens, more than two thousand people left for the safety zone, where mobile Red Cross stations were activated.
As a result, it became known that two people died and 28 others were injured.
The earthquake resulted in a minor tsunami that reached a maximum height of 40 cm (15.7 inches) in Kapoho, 20 cm (7.9 inches) in Hilo and 15 cm (5.9 inches) in Honuapo.
Loma Prieta
The Loma Prieta earthquake was a 1989 earthquake that occurred in Northern California on October 17 at 17:4 local time.
The epicenter of the earthquake was located approximately 16 km northeast of the city of Santa Cruz on the San Andreas fault. The earthquake was named after the highest point in the range of the Santa Cruz mountain range – Loma Prieta Mountain.
Intensity and spread as a video animation
The city of Santa Cruz suffered the most damage and losses. As a result of the earthquake, more than 18 thousand houses were destroyed, 63 people were killed and 3757 were injured. The total material damage was estimated at almost $6 billion.
Earthquake in San Francisco
The 1906 San Francisco earthquake was an earthquake that occurred at 5:12 am (local time) on April 18, 1906. The epicenter was located 3 km west of San Francisco, intensity of surface waves on the Richter scale was 7.7, seismic moment – 7.9.
The tremors were felt from Oregon all the way to Los Angeles, and inland to the center of Nevada. The earthquake and subsequent fires killed up to 3,000 people, left 225,000-300,000 homeless, and destroyed 80% of buildings in San Francisco.
The earthquake was accompanied by ground displacements along the San Andreas fault of up to 6.0-8.5 m. The displacements were observed in its northern third on a 477 km long section.