Magnitude is a measure the amount of energy released during an earthquake. It uses the Richter scale. There is one thing about the Richter scale most of us don’t know about and that is it is open-ended which means it will measure an earthquake no matter how small or how large it is. If we look at a table which is of recorded earthquakes for the last forty-seven years we can see that earthquakes with magnitudes of 7.5 to 7.9 occur only 3.1 times in the year. Earthquakes which range from 8.0 to 8.4 occur only one 0.1 times in the year and earthquakes which range from 8.5 to 8.9 only occur 0.3 times a year which really means we should only be seeing them in a little over three years. An earthquake with a magnitude of 5.0 has a shaking power which is ten times greater than an earthquake of a 4.0 magnitude.

New Zealand is a group of islands which are on top of a collision zone between the Indo Australian and Pacific tectonic plates and it is part of the Pacific basin Ring of Fire where many earthquakes occur and volcanoes erupt. Recently an earthquake of a magnitude of 7.8 shook New Zealand and something was seen which shocked the residents of Kaikoura, South Island. What they saw were areas of the seafloor which had been elevated through the island up to two meters above ground. It happened so fast some of the Marine life was still in these areas. One picture showed a hapless lobster who must’ve really been surprised. One scientist said they had never seen anything like it before during an earthquake. The quake was especially bad, because of a phenomenon known as co-seismic movement. What this meant was two simultaneous earthquakes acted upon the fault lines concentrating their energy there. GPS has indicated Cape Campbell and the Marlborough region has moved northeast by 2 to 3 meters. Some believe parts of New Zealand will sink back into the ocean.

Another area of the world which has been suffering from earthquakes and tsunamis is Japan. We all know what happened when a tsunami reached the walls around the Fukushima reactor releasing deadly radiation. In 2016 Kumamoto, Japan was hit with a series of earthquakes including one which was of a 7.0 magnitude. As the bigger earthquake hit over three thousand were injured and fifty killed. Many buildings were destroyed. Over forty-four thousand people had to be evacuated from their homes. Japan was then hit with some smaller tsunamis. Japan is also located along the Pacific Ring of Fire and is on the edges of several continental and oceanic tectonic plates. As far as earthquakes and tsunamis which are caused by them go, Japan is not in a very envious position.

In the United States there are several states which get the most earthquakes, the leading one is Alaska, which is followed by California, Hawaii, Nevada, Washington, Idaho, Wyoming, Montana, Utah and Oregon. You will notice that the entire West Coast is listed along with some states which are further inland. The West Coast of the United States is also part of the Pacific Ring of Fire. One thing we have to realize about earthquakes is just because they are centered in one state doesn’t mean they won’t produce damage in another. There are a few states which have had no earthquake activity in the last thirty years. One of these states is Florida. When we look at the Eastern part of the United States we see a lot of states which have very low earthquake activity such as New York, Pennsylvania, Virginia etc. Many of these states are on the Eastern Seaboard, but some are in the Midwest. This doesn’t mean that these states don’t have fault lines, because many of them do, but they haven’t been active recently. The great earthquake that hit San Francisco in 1906 had a 7.9 magnitude. This was only one tenth of a point higher than the one that hit New Zealand.

In 1964 an incredibly powerful earthquake hit Alaska, and had a magnitude of 9.4. This earthquake had a couple of different names, the 1964 Alaska earthquake, the great Alaskan earthquake and Good Friday earthquake. It was a miracle only one hundred and thirty-nine people died. “Only” hardly seems to be the correct word. The earthquake traveled across south-central Alaska and caused ground fissures and collapsed structures and tsunamis which were the result of the earthquake. It lasted four minutes and thirty-eight seconds and was the most powerful earthquake ever recorded in North American history.

In 1960 a 9.5 magnitude earthquake devastated Chile. This was the most powerful earthquake ever recorded. Some scientists claim it was actually a 9.6 magnitude earthquake. The earthquake originated off the coast of southern Chile on May 22, 1960. Not only did the earthquake cause massive loss of life, but so did the tsunamis it generated. It hit a hundred miles off the coast parallel to the city of Valdivia. The day before an earthquake of a magnitude of 7.9 had caused major destruction in the city of Concepción. The Nazca Plate went under the South American Plate. In some cities nearly half of the buildings were destroyed. The earthquakes caused loss of life, but the tsunamis were even more destructive as far as loss of life. The seafloor had shifted so much that even fifteen hours later the Hawaiian Islands which are 6,200 miles away still had waves which crested at thirty-five feet in some places.

The US geological survey states it is normal to have periods of increased and decreased seismic activity. While some people are worried, because they believe seismic activity is increasing, scientists are telling us this is not unusual. I think the real question may be does global warming have an effect on seismic activity? One scientist stated he gets really annoyed when he hears people say earthquakes can be caused by global warming and states they are only caused by earth’s natural processes. Other scientists are not so sure. One geologist says climate change and rising sea levels along with melting glaciers could bring earthquakes, volcanic eruptions, tsunamis and landslides. I don’t think there is any doubt a huge chunk of ice falling into the ocean could create a tsunami and maybe this ice fell in because of the melting process, but I’ll leave it to you to decide.