MAPPING OF POTENTIAL MINERAL HAZARDS IN CALIFORNIA – PROTECTING PUBLIC HEALTH AND SAFETY AND THE ENVIRONMENT

The term “natural hazards” typically evokes earthquakes, floods, volcanic eruptions, and other catastrophic phenomena. Deservedly, these have received much publicity and funding for preparedness and mitigation. Mineral hazards, however, are generally not striking nor are they well-established in the public consciousness. Nevertheless, they have potential, locally and regionally, to adversely affect public health and safety and the environment. We use the term “mineral hazards” in a general way to include naturally occurring earth materials that may be harmful to humans and the environment. We also include features related to mining, particularly those associated with mineral commodities that can be harmful. Since the 1990’s, the California Geological Survey has prepared maps and reports that address various types of mineral hazards in different parts of the state. These products are designed to guide users with little or no geologic background in understanding where mineral hazards may be present. Users range from the general public to policy-makers to technical specialists in non-geologic disciplines as well as geoscientists. Applications of these products include purchase of property or homes, design and maintenance of roads, fighting forest fires, use of recreational trails, epidemiological studies, and many others. Types of potential hazards investigated include asbestos, radon, mercury (both mining of it and its use in gold mining), and several other metals and metalloids that can be naturally present in elevated concentrations in geologic materials. In addition, we have been using various digital tools and products to improve reported locations of mines and prospects, which may be sources of physical and chemical hazards. Basic geologic maps are the essential core sources of data, to which we add many other sources of data, all of which are integrated and analyzed with GIS tools to ultimately derive the mineral-hazard maps. The GIS tools allow us to prepare a variety of products for users ranging from those who have little or no familiarity with computers to those who routinely use digital data in mapping software. Together, the maps and companion reports continue to expand both awareness and mitigation of mineral hazards in California.