Settlers not discouraged by Mt. Diablo’s shaking ground

Long, long ago, the land around Concord was filled with water.

History books tell us that earthquakes deep from the middle of the earth produced our hills and mountain ranges.

Early settlers found the Concord area as an open fertile valley, carpeted with waving grass, shaded by great oaks and watered by swiftly running streams full of fish. They named the mountain Mt. Diablo.

The valley floor was made of adobe soil and sandstone, interlaced with coal deposits formed by flowing water. Geologist have discovered that rocks in this area, now called the Diablo Valley, range from Cretaceous fossils to superficial detritus.

The mountain formed eons ago, and millions of years of erosion molded the mountain that greeted the newcomers.

Then, as now, earthquakes occurred. The early arrivals had no idea that the place they’d selected was between the South Hampton fault to the east and the Mt. Diablo fault to the west. Both connect to the major San Andreas fault. A third fault, the Concord fault, ran right through their land.

A photo of Mt. Diablo from the Concord side taken circa1937, long before development took over. (Photo courtesy of Contra Costa Historical Society)

In the earliest recorded earthquake report, Concord founding father Salvio Pacheco wrote: “From 1824 to 1826 … earthquakes were very frequent and … (so) severe, in some localities, as to throw down adobe houses and bury inmates in the ruins.”

A quake also shook the Concord area on Oct. 21, 1868 – the first earthquake recorded after the area was settled by Americans.

The most famous quake to affect Concord was the San Francisco quake of 1906. A Concord resident reported that the ground shook like waves. Windows broke, household items were tossed about, plaster tore off walls and chimneys fell – including one of John Muir’s chimneys, which fell onto the front porch.

In the beginning, however, the newcomers were delighted with the nearly ideal climate. From Indians and Spanish explorers and settlers to Yankee farmers and 20th century commuters, Concord has beckoned many to make their homes in this rich valley.

It’s easy to see why Concord, with its central location, temperate weather and beautiful setting, has been the choice of so many.

Carol Longshore has been a Concord resident since 1950. She is a community leader and past president of the Concord Historical Society. Send comments and suggestions for future topics to