Short noteiSeismometer: A geoscientific iPhone application
Introduction
In the last few years, smartphones and similar handheld devices have evolved into fully integrated technology platforms which are used frequently and distributed widely. The second generation Apple iPhone is a prominent example which integrates a telephone, touchscreen, wireless internet access, global positioning system (GPS) receiver, accelerometer, light sensor, camera, speaker, proximity sensor and microphone. Due to their small size, light weight, long battery life, numerous utilities, and connectivity, the more than 21 million iPhones sold as of the second quarter of 2009 are likely to be constantly in use throughout the world.
Software developers recognize a strong market for smartphone applications. Between the opening of the App Store in July of 2008 and the end of the first half of 2009, Apple reports availability of more than 50,000 applications reviewed and approved by their staff, with the number of downloads reaching one billion in April of 2009. We have developed a free application we hope will be useful in geoscience education and research. iSeismometer version 1.0 uses the iPhone’s built-in accelerometer to record and display motion. iSeismometer can currently be used in education, and has potential future use as a component of an earthquake early warning systems (EWS).
Our choice of the iPhone platform was based on the current edge we feel Apple has in integrating technologies and distributing applications. Other major operating systems (OS) for smartphones with varying degrees of openness are: Symbian, Android, Blackberry’s Storm, and Palm’s webOS. As one example, Android is a mobile open source community OS platform led by Google which allows any hardware manufacturers to integrate Android into their devices, but these will not necessarily contain a GPS or an accelerometer. We also chose to develop iSeismometer for the iPhone because: (1) Apple was first to launch a storefront for downloadable applications with its App Store, while all other platforms are hurrying to catch up and compete; (2) Apple has a relatively low barrier to entry for developers in terms of offering support, documentation, and a low registration fee; (3) Apple’s unified platform and OS (including organized version upgrades) lowers the development risk. We continue to monitor the volatile mobile market for the potential of developing and running our application on other platforms.
Section snippets
iSeismometer description
Apple's iPhone specifications (http://www.apple.com/iphone/features/accelerometer.html) describe the accelerometer’s functionality; “The accelerometer inside iPhone uses three elements: a silicon mass, a set of silicon springs, and an electrical current. The silicon springs measure the position of the silicon mass using the electrical current.” In essence, the accelerometer behaves like a plumb-bob. When a user places an iPhone flat on a table and face up, three coordinates, (X, Y, and Z in
iSeismometer evaluation
In terms of efficiency of frequency spectrum calculation, the FT used in iSeismometer 1.0 has a computation cost of O(N2). Using 3 s of data (300 float values), the actual computational time is about half a second per axis; however, this increases exponentially so that using 10 s of data take over 6 s per axis. In version 1.1, we implement a fast Fourier transform (FFT) which uses a discrete Fourier transform (DFT) and applies a “divide and conquer” algorithm. This lowers the computational cost to
iSeismometer applications
iSeismometer has numerous classroom and laboratory applications. Students could mimic primary (P-wave) or secondary (S-wave) seismic waveforms while walking across the room by moving an iPhone in the correct direction(s) of particle motion. Students could also attempt to match the frequency of historic earthquakes. Using a long flat surface, multiple iPhones document attenuation in amplitude with distance. Comparing traces from an iPhone on a table and one floating in a container of water
Related work
Other computing devices have much or all of the functionality described above, but these may not currently be as seamlessly integrated. For example, SeisMac 〈http://www.suitable.com/tools/seismac.html〉 is a Mac OS X application which displays seismic traces for educational purposes on MacBooks and MacBook Pros. Quake Catcher Network (Lawrence et al., 2008; 〈http://qcn.stanford.edu/〉) is a laptop-based seismic locator network begun last year, but requires fairly high-end laptops with built-in
Conclusions
iSeismometer illustrates how mobile applications offer new opportunities for geoscience software developers to focus on user interaction with the computer, and how the computer interacts with the environment. Developers may also consider the utility of an application’s distribution model. While not unique to Apple, its Apps Store tracks the number of downloads and feedback regarding usability of an application. iSeismometer, for example, has had over 120,000 downloads since March 2009, and
References (4)
- et al.
The potential for earthquake early warning in southern California
Science
(2003) - et al.
Earthquake early warning starts nationwide in Japan
EOS Transactions. American Geophysical Union
(2008)
Cited by (15)
Review of Recent Developments in Sensing Materials
2014, Comprehensive Materials ProcessingSedMob: A mobile application for creating sedimentary logs in the field
2014, Computers and GeosciencesCitation Excerpt :The above-mentioned features are employed by scientists for Earth observation (Pavlis et al., 2010). Mobile devices are used for recording GPS coordinates, measuring the orientation of geological structures (Weng et al., 2012; Lee et al., 2013), as well as in geological mapping (Pavlis et al., 2010), geoeducation (Peña et al., 2011), earthquake detection (Takeuchi and Kennelly, 2010), and for collecting various types of geological (Malinconico et al., 2011) and other Earth observation data, also with public participation (Ferster and Coops, 2013). Laptops, personal digital assistants (PDAs) and early pen tablets have been used since the mid-1990s (e.g. Clegg et al., 2006); however only the latest development of advanced mobile (cellular) telephones, commonly referred to as smartphones, has made mobile technologies available to a vast portion of the world׳s population.
Review of Recent Developments in Sensing Materials
2014, Comprehensive Materials Processing: Thirteen Volume SetFeasibility of employing a smartphone as the payload in a photogrammetric UAV system
2013, ISPRS Journal of Photogrammetry and Remote SensingCitation Excerpt :Numerous research projects are underway to study their diverse applications. Takeuchi and Kennelly (2010) and a research team at the University of California (CITRIS, 2011) evaluated the possibility of using a smartphone equipped with an accelerometer as a seismic sensor. Poduri et al. (2010) developed an application for visibility monitoring using the camera, compass, accelerometer, and GPS, all of which are built-into many smartphones, and Langlotz et al. (2011) developed a mobile augmented reality (AR) application using a smartphone to detect and track annotations.
Roadmap for earthquake numerical forecasting in China-Reflection on the tenth anniversary of Wenchuan earthquake
2018, Kexue Tongbao/Chinese Science BulletinUsing free/libre and open source software in the geological sciences
2017, Austrian Journal of Earth Sciences