Broadband Terminology
From SCECpedia
Jump to navigationJump to searchTerminology
To help the engineers, seismologists, and computer scientists talk about this computational study, we have defined the following terms for use in broadband calculations:
- Study - A well-defined set of calculations to be performed. To qualify as a "study", the problem must defined to the level of detail that a knowledgeable user could calculate the total number and type of output files that will be calculated. We are currently conducting the Fling study.
- Scenario - A scenario refers to a general description of an earthquake as observed by a particular set of stations and for a specified velocity model. The earthquake scenario is defined by magnitude, fault dimensions (length, width, depth, segmentation) and fault geometry (strike, dip, average rake). A scenario does not define the details of the rupture history (slip distribution, slip time function, rupture speed), and does not define hypocenter location. The Fling study has 42 scenarios, numbered 101 to 142.
- Source Realization - Earthquake source definitions, given as a part of a scenario, are elaborated into distinct source realizations. Source realizations may differ by initial stress distribution, slip distribution, slip time function, hypocenter location, and rupture velocity. In the Fling study, each Scenario has 30 source realizations. A broadband source realization is equivalent to a "rupture variation", a term used in SCEC CyberShake work.
- Simulations - A Broadband platform simulation is defined by an invocation of the main program, called run_bbp.py. A simulation is defined by a source realization, a station list, and a set of Green's functions to use. In the Fling study, we run a simulation for each source realization.
- Seismograms - The smallest unit of computational work in a broadband simulation is a seismogram. In broadband, a seismogram refers to a 3 component seismogram associated with a site. At a minimum, the relation between the source location and the site is known. In many cases, the geographical location of the site is known. In the Fling study, the number of seismograms is determined by the number of stations in the station list each simulation. For Fling scenarios with smaller magnitude earthquakes, the station lists may have 96 stations. Scenarios with larger magnitude earthquakes may have up to 279 stations. More stations are typical for larger earthquakes because strong ground motions are expected over a larger region. We will calculate the total number of seismograms and use that as a computation metric for the Fling study. Below is a table showing the number of seismograms for each scenario.
