Lew on the right discussing the Cypress Point Fault with John Logan on a previous MBGS field trip.


GSA Superior Practice - Field Mapping 2012

1959 - 2013
Lew Rosenberg was an outstanding true geologist in an ever-shrinking world of “real” geologists. He built his professional career as a field-oriented engineering geologist and paid special attention to the work of other geologists before him for whom he admired, so that his work could develop upon the collective geologic knowledge base.

Lew effectively bridged field geology expertise with his mastering of computer technology to create digital geologic maps on a wide variety of projects, both small and grand in scale.

He received his bachelor’s degree in geology from New Mexico Tech, and his master’s degree in geology from San Jose State University. He was a licensed geologist in California, Oregon, and Wyoming, and was accredited as a Certified Professional Geologist by the American Institute of Professional Geologists. His fields of specialization included landslide and earthquake hazards, groundwater, geologic mapping, and translating geology for planning. Lew was author or co-author of eight reports published by the U.S. Geological Survey.

Lew’s practice reflected his esteem for the work of his mentors that he had the honor and pleasure to work with during his career, as well as the work of other notable geologists for which Lew tirelessly researched, chronicled, and documented. Lew’s contributions to geologic science for present and future practitioners are enormous, but in scientific terms, also quite describable. The following lists a representative but not exhaustive assemblage of projects that Lew worked on, which have collectively led to a clearer understanding of local and regional geology along California’s Central Coast:
 1991 exploratory trenching work along Calaveras fault, Hollister
 1993 research on Quaternary faulting and landslides in Carmel Valley (master’s thesis)
 1994 NEHRP Investigation of Quaternary faulting in the greater Monterey area
 1997 digital geologic mapping update of the 7.5’ Monterey and Seaside quadrangles
 1998 engineering geologic investigation in the Sleepy Hollow area of Carmel Valley
 1998 liquefaction susceptibility mapping, Hollister
 2000 digital geologic mapping update of the 7.5’ Spreckels quadrangle
 2000 Monterey County comprehensive geologic bibliography
 2001 Geologic Mapping contributions to Monterey County General Plan Update
 2002 updated geologic mapping of the Laguna Seca Subarea
 2002 prepared GIS map database for Paso Robles Basin groundwater study
 2003 hydrogeologic framework refinement for the Deep Aquifer investigative study near Marina
 2003 San Simeon earthquake investigations
 2004 Rinconda and Reliz fault zone investigation, Salinas Valley
 2005 updated geologic mapping of the Seaside Groundwater Basin
 2005 research on slip rate of San Gregorio-Hosgri fault zone
 2005 ArcGIS formatting for Cambria 30 x 60’ quadrangle map
 2008 contributions to the update of the New Mexico Natural Hazards Mitigation Plan

Lew’s varied interests in geology led him down many exploratory paths. Over the course of his colorful career, Lew wore many hard hats and left his mark while engaged as:
 A volunteer scientist with the US Forest Service
 An engineering geologist with an internationally recognized consulting firm (FUGRO)
 A private consulting geologist (Tierra Geoscience)
 A contract geologist with the US Geological Survey
 A planning geologist for Monterey County
 County geologist for San Luis Obispo County
 City geologist for Hollister
 A college geology instructor (Hartnell College)
 A guest speaker, short course teacher, field trip leader and expert witness

In Lew’s words, one of his most challenging yet rewarding experiences was building the position of San Luis Obispo County Geologist from scratch. It involved raising the local state-of-practice essentially instantaneously and took much effort to educate county staff, decision-makers, consultants, and developers. This resulted in better geology being used for better planning decisions in a rapidly growing part of the state that formerly did not use geologic information.
Lew had the good fortune to work with many of the iconic geologic “old timers” of the Central Coast, including Tom Diblee. In 2004, while Tom was still alive, the San Luis Obispo 7.5-minute quadrangle map was dedicated in Lew’s name, stating: “This map honors Lew Rosenberg, for his years of dedication in helping others understand the geology of San Luis Obispo County and the central Coast Ranges.” As another fruitful encounter, Lew recalled that a chance telephone call to USGS landslide expert Earl Brabb in 1988 resulted in a many lessons, both of the career and life variety. Lew said that Earl greatly improved his field mapping skills, landslide knowledge, and instilled the maxim to do things right. Lew had a knack for being in the right place at the right time and once commented on being outside during the 2003 M6.5 San Simeon quake and seeing ground waves in the pasture at his ranch near Templeton. Lew reflected that even though he had experienced the 1971 Sylmar and the 1989 Loma Prieta quakes, seeing the ground roll was alternately fascinating and frightening, and it reinforced his respect for the geologic forces that the earth could whip up.

For all his geologic knowledge and expertise, Lew also possessed other life interests, which he explored with gusto. He painstakingly restored a vintage 1968 Ford Bronco that he rescued from a pasture of obscurity, and he had a lifelong fascination with farm tractors, including his very own John Deere 5203. But likely his primary passion was raising milk goats with his wife Doreen on their second ranch, this one located in a remote region of New Mexico south of Albuquerque (think “The Milagro Beanfield War”). Here is where Lew found true peace, right up to his last day.