STRUCTURAL GEOLOGY WITH A MOBILE PHONE?: TESTING SMARTPHONE APPS FOR STRIKE AND DIP

In geological mapping, attitudes of rock strata are described by measuring strike and dip. In the field, the locations and attitudes of strata can make taking strike and dip physically difficult, even dangerous. Recently, smartphone apps have been developed that take strike and dip measurements quickly and simply, and even locate them with mapping coordinates. This has provoked debate among geologists as to their usefulness, especially their precision and accuracy. It is expected that a conventional magnetic compass will be more precise as well as accurate, but there is an argument for being able to take measurements quickly and easily, especially in physically challenging situations. Under the assumption that since the app reads the phone’s internal hardware and therefore the choice of app will not affect the results, I tested one application, GeoClino Free, on two Android phones for accuracy and precision. Results of these tests confirm that the Brunton compass gives more precise results. While the precision of the compass is to be generally preferred, these tests also show that the variance in readings given by the app can be within a tolerable range for geologic mapping, especially if a larger number of measurements is taken, which is expedited by the ease of making measurements that the app facilitates. While it is unlikely that the Brunton will be replaced anytime soon, especially within the ranks of the most discriminating geologists, the convenience and safety offered by the smartphone app are appealing enough to warrant its use in certain situations.