In ‘The Great Quake,’ how Alaska’s Good Friday Earthquake overhauled our understanding of the planet

The Great Quake: How the Biggest Earthquake in North America Changed Our Understanding of the Planet

By Henry Fountain; Random House; 2017; 298 pages; $28

The 1964 Good Friday Earthquake, the strongest ever recorded in North America, remains a pivotal event in Alaska's history, but its impact on the science of geology was even more significant. Our understanding of the planet itself was permanently altered by what occurred that day. This we learn from New York Times science journalist Henry Fountain's recently published book, "The Great Quake," which explores the catastrophe and its aftermath on three levels.

The first and most obvious story that Fountain examines is the earthquake itself. Ultimately assigned a magnitude of 9.2, it hit on March 27, 1964, at 5:36 p.m., lasting for four to five minutes. 139 people perished, most of them lost not in the violence of the quake, but in the consequent tsunamis that took lives along Alaska's coast and as far away as Oregon and Northern California.

The middle third of Fountain's excellent book is a vivid and detailed account of the quake, the tsunamis, and the days that followed, as stunned and grieving survivors confronted the wreckage their world had suddenly become. The gripping narrative is drawn from interviews, reports from the time and later recollections of those who were there.

In Anchorage, entire neighborhoods slid to the shore while one side of Fourth Avenue dropped 10 feet. The city suffered extensive damage, but surprisingly few deaths.

Not so Valdez, where the ground liquified and the shoreline sank, swallowing some 30 people. Just offshore, a 441-foot cargo ship that had arrived earlier that day was thrust about so violently that at some points its propeller rose above the tops of roofs. Successive tidal waves rolled over the town and claimed still more lives.

Meanwhile, out in Prince William Sound, the Alutiiq village of Chenega, which clung to the shore of an island of the same name, was struck by a tsunami that reached 70 feet above sea level before retreating. About a third of the tiny community's approximately 80 residents were swept away in the backwash.

Fountain writes of "hemlocks that had been snapped in half at midtrunk height; spruces that were split vertically as the ground cracked beneath them; heavy equipment that had been moved hundreds of feet; hillsides that had been stripped bare of vegetation by the scouring action of water; 1-ton boulders found halfway up slopes; roads split down the middle and sunk 10 feet or more on one side; rail lines in tangles; brick building facades in jumbled heaps; cars upside down; houses upside down; boats littering streets."

The top 500 feet of a mountain near Cordova collapsed down a nearby glacier. Fires erupted in the town itself. It would be rebuilt, as would Anchorage. Valdez was relocated 4 miles away on more stable ground. Chenega was simply abandoned, with some of its surviving residents later establishing a new community on the mainland.

The second part of Fountain's story is about George Plafker, a mineral geologist who worked for the U.S. Geological Survey. Though based out of California, he had been assigned to Alaska for several years and was well familiar with its geology. The day after the earthquake he was sent north to report on the damage, and it would ultimately fall on him to explain what caused the quake.

At the time, Plafker had only completed his BS and was a field geologist, not a theorist. As someone who valued hands-on work over desk and lab studies, he had spent months traveling Alaska by foot, learning how it was assembled. This made him the perfect person to figure out what had happened. His finding would play a major role in the revolution that was taking place in the science of geology during the 1960s, the third theme of this book.

A seismic shift

At the time of the disaster, continental drift – the notion that the planet's crust is comprised of numerous plates continually moving against each other – was still a controversial idea in geology. The prevailing view held that the planet was essentially stable, and that earthquakes were caused by vertical faults like the famed San Andreas Fault in California that triggered the 1906 San Francisco quake. Indeed, the first paper published on the Good Friday Earthquake, authored by a highly esteemed Ph.D geologist, postulated that some undetected vertical fault was to blame.

Plafker, however, knew from looking at the results of the quake that vertical movement could not explain it. Parts of Alaska had sunk and other parts had risen. The only viable reason would be a horizontal fault. Aware of the debate within his field over what is now known as plate tectonics, Plafker concluded that the quake had been caused by the subduction of a plate underneath the Pacific Ocean pushing beneath the plate underlying coastal Alaska. Pressure in the contact area reached a breaking point and it all slid, wreaking massive havoc in the doing.

Plafker's paper on his findings was accepted by the journal Science. He became a celebrity in geology circles and later went on to earn a Ph.D and devote his career to earthquake studies. A humble man who, as we learn in this book, became a geologist almost by accident, he successfully challenged the longstanding beliefs of renowned researchers and was a key figure in the complete overhaul of our understanding of the planet.

The scientific side of this story is told in greater detail in Jerry Thompson's 2011 book "Cascadia's Fault." Although primarily concerned with the fault along the Pacific Northwest coast that presents a looming threat of massive proportions, Thompson also explores Alaska's quake, Plafker's findings, and the emergence of plate tectonics as the theory that explains modern geology. It's a worthy companion to this book.

Fountain's volume is more narrowly focused on one event and its ramifications and tells the Alaska part of this story more thoroughly than any currently available work. Even most state residents are likely unaware of the role our earthquake played in reshaping geology. It was tectonic on more than one level.

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