Day of the Earthquake written on April 24th, 2009

The Day the Earth Tore Apart
The question as to why some structures withstand earthquakes and others fail has perplexed engineers for decades. In this article, Lodge Log and Timber Products, a leading manufacturer of log homes for over 15 years, discusses critical issues in seismicresistant design. During the 1989 Lama Prieta earthquake, four Lodge Log and Timber Products homes suffered no structural damage – even though all were located within only a few miles of the quake’s epicenter.
A conventional framed structure near Boulder Creek, California is left in ruins in the wake of the Loma Prieta earthquake, while a Lodge Logs home located only a few miles away received no structural damage.

Seismologists and engineers had long predicted it.Yet, few Bay Area residents were prepared for the catastrophic events of October 17, 1989.

At 5:04 p.m., as commuters clambered onto freeways, and baseball fans converged on Candlestick Park for the third game of the World Series, shock waves measuring 7.1 on the Richter scale ripped through San Francisco and surrounding communities. Fifteen seconds later, entire neighborhoods were reduced to rubble, thousands were left injured or homeless and 61 people lay dead. Estimates of damage were staggering: over $6 billion for the Bay Area.

Understanding Lorna Prieta. With its epicenter located on the San Andreas fault about 10 miles northeast of Santa Cruz, the Lorna Prieta earthquake was the strongest to hit San Francisco since 1906. Yet, most experts agree that the worst – what residents call “the Big One” – is yet to come. And when the Big One does arrive, it may not be San Francisco which gets hit. The U.S. Geological Survey has identified a dozen large cities across the United States which it considers to be at high risk of a major quake. Why does it happen? In the aftermath of seismic disasters, questions arise as to why some structures ail, while others – perhaps only a few feet away-survive. As was noted in the wake of the tragedies such as Soviet Armenia, where thousands of people lost their lives, earthquakes do not kill people. . . crumbling structures do. Earthquake damage results from ground displacement, velocity and acceleration. The ground moves, the building resists, and the opposing forces create structural stress.The way a structure reacts depends upon factors such as properties of the earthquake itself, type of soil, as well as the mass, shape, flexibility, and damping of the building*.

Why did Lodge Log and Timber Products homes survive? Lodge Log and Timber Products is one of the most structurally sound log home packages on the market. Each log is precision milled, and our floor-to-ceiling “thru-bolt” wall assembly secures the logs with an exact fit and excellent structural stability even under the severest conditions. Lodge Log and Timber Products sells only quality, stressrelieved, cured Lodgepole Pine. This helps eliminate cracking, warping and shrinking. Lodge Log and Timber Products are tongued and grooved and milled to a close tolerance. The logs are pre-drilled to our bolt system, which secures the entire wall to the foundation. Bolts are placed on either side of the windows, doors and fireplace openings, approximately four to six feet along each wall. Coupled with our microfoam sealer between logs, this adds to the structural integrity and ensures a tight fit. Other manufacturers use a time consuming spike system which aggravates cracking.
*M.L. Wong, ” Architectural strategies in seismic design,” Architectural Record (February 1986): 136-143

“Not one window was broken, not one log moved, just pictures looked a bit askew”
Kenneth and Patricia Kulzick
Lodge Log and Timber Products homeowners
Santa Cruz, California
In the aftermath of Loma Prieta, Lodge Logand Timber Products homeowners reported little or no structural damage to their homes. Kenneth and Patricia Kulzick, whose home is located in the mountains of Santa Cruz wrote as follows:
“With great pleasure, we salute the people of Lodge Log and Timber Products. Without your skill and knowledge, October 17, 1989 would have brought us despair and wreaked economic havoc. Our much loved Mohega (which means “flower of the forest” ) withstood the earthquake much as a butterfly holds onto a branch in a heavy wind. We are certain our Mohega will still be there, as beautiful as ever, in the 21st century. Thank you for giving us such a lovely spot to call home.”

A conventional framed home in Boulder Creek – completely demolished.

Lodge Log and Timber Products homes in Santa Cruz (left) and Watsonville (right) with no structural damage

Of course, no manufacturer can guarantee its homes will always survive an earthquake. But at least four Bay Area families have discovered the security and peace of mind that comes from owning a Lodge Log and Timber Products home.

For the Lodge Log and Timber Products dealer nearest you, call (800) 533-2450. Within Idaho, call (208) 336-2450. Or write us at 7789 S. Federal Way, Boise, Idaho 83716.