NAME

dbloc2 - interactive hypocenter location

SYNOPSIS

dbloc2 [-r] [-p pf] db

DESCRIPTION

dbloc2 is a collection of several programs which run together under the control of a perl script, dbloc2. It facilitates the location of hypocenters from previously picked trace data, while allowing interaction with the location program and the ability to edit arrival picks. It can also attempt to associate groups of arrivals with other catalogs, for instance the PDE or REB catalogs.

You must begin with a database db which contains at least site and arrival. If you wish to display waveforms and add picks, you must also have wfdisc, sensor, sitechan, and instrument. The arrival, origin, assoc, event and lastid tables must be writable. Generally, you run dbloc2 from the directory containing the database or in a directory with a database descriptor file which references the database.

Note that if more than one person is running dbloc2 simultaneously on a database, they should agree among themselves on how to split up the events, so that everyone is working on different events.

It's important that the database itself be self consistent: run dbcheck(1) and dbverify(1) on the database before starting dbloc2 if you have any question or are just beginning to use dbloc2.

Start the program with:


dbloc2 your-database

The main window should be fairly easy to understand. From top to bottom, there are several different panels, corresponding to the sequence of operations to locate events.

Grouping Panel

dbloc2 first groups arrivals together using a time window. Directly under the menu bar are a set of buttons and sliders which control this grouping operation. Basically, you can control the time window size and the start time. When you're reviewing a catalog, you can choose to search for unassociated arrivals; associated arrivals may still appear, but the grouping skips past arrivals which are already associated.

Arrival Panel

Arrivals are displayed graphically in the next lower panel. The station name is displayed along the left edge, along with a distance in degrees. The names appear on buttons which bring up menus to display some additional information. In the main body of this window, each arrival appears as a button. Arrivals here have three states: selected, ignored, residual only. Selected arrivals are fed to the location program; ignored arrivals are not. Finally, some arrivals may not participate in the determination of the location, but the location program does calculate a residual.

You may toggle between selected and ignored with the left mouse button on an arrival button, or set to residual only with the middle mouse button. The buttons visually indicate the current state.

Pressing the right mouse button on an arrival brings up a menu showing more information about the arrival and allowing you to select or ignore azimuth and slowness associated with that arrival (if these were measured).

You may also select a collection of arrivals by dragging the mouse around them. This is faster for a large collection than individually selecting each. Shift drag zooms in on a smaller portion of the time window, sometimes making it easier to select arrivals. (Beware: the motion is subtly different from the corresponding dbpick zoom. It's not a shift-click-release, shift-click-release, but rather shift,click,drag,release-button,release-shift. Occasionally, you may click multiple times by mistake and the screen may then take a long time to recover).

There is a row of buttons along the bottom of the arrival panel which may help select certain arrivals. The "Show map with reporting stations" button brings up a new window showing the arrival locations and origin locations.

Origin Panel

The origin panel shows the current "working set" of origins. This includes

By default, after origins are displayed and when the analyst goes on to the next event or quits, the review field in origin is set to y. This behavior may be modified using the radio buttons Mark reviewed, Leave as-is, and Mark NOT reviewed

dbloc2 accumulates a set of origins and associations in a temporary database: tmp/trial. It's up to the user to select the origins from this which should be saved back to the main database (or kept in the case of origins already in the database). This is done with the second column of buttons in the origin panel, which toggle between Keep/Delete/Reassoc/Chop for previous origins, and Drop/Save for new origins.

When an arrival associated with a previous origin is moved or deleted, the database has been compromised. dbloc2 detects this situation (by running dbloc_verify to compare lddate in the origin, assoc and arrival tables). In this situation, you have the following choices:

You must also select a preferred origin if there is more than one origin per event, using the third column radio button.

If there are multiple events in the time window, it may be necessary to explicitly set the event id (evid) using menus under the the leftmost column of buttons.

You may set the etype field in origin by using the menu under the Etype column. The default set of selections is qb, eq, me, ex or - (null), but you may change this by using the etype parameter in the parameter file.

The menus under the left column also allow rearranging the arrivals display to a) select only the associated arrivals, and b) show the residuals graphically using arrows and by removing the moveout (predicted travel time) for each arrival. The latter operation makes the time scale in the window relatively useless, but tends to put all the P and S arrivals in straight vertical line.

Location Panel

The next panel down runs location programs. You can choose a program and a travel time model. You can fix the depth and try different starting locations; many programs are sensitive to the starting location. Generally, dbloc2 sets the location of the first station as the starting location.

You can also start the location from any already existing origin, using an option under the menu for that orid.

By experimenting with starting conditions, fixing the depth, choosing other models, selecting different arrivals and perhaps adding or adjusting arrivals, you may be able to find locations for grouped arrivals. There are also situations where a location is elusive; this may arise due to model problems, due to overlapping events, due to timing errors, inadequate data, or even problems in the database. (If you suspect the last, run dbverify(1) on the data).

Waveform Panel

dbloc2 coordinates with dbpick(1) to display waveforms if they're available. The controls are a bit confusing, however. Generally, you should use the Show waveforms button to bring the dbpick(1) display to the front, or Hide waveforms to iconicize dpbick. Other controls in this panel affect whether predicted arrivals are shown, how many channels appear in the dbpick window, and what channels (all, only z, only channels with arrivals).

If the arrival panel is showing a modified time scale with moveout removed, the dbpick window does also.

It's possible to bring up a single station to inspect an arrival pick using a menu option under the right mouse button on an arrival in the arrival panel.

Status line

dbloc2 prints short messages into a scrolling one-line window just above the button bar at the bottom of the screen. The window can be scrolled using the arrows on the right. The View->error_log menu brings up a window with all these messages and errors which is sometimes more convenient.

Button Bar

Along the bottom of the dbloc2 window are a number of buttons, which correspond to the usual sequence of actions: Next (group of arrivals), Locate (using selected arrivals), and Associate (using selected arrivals). Each Next action saves any origins which have been marked to save.

Under the right mouse button, there are additional menus for Next and Associate. The Next menus allow associate and next to be called after each next action. The Associate->Controls option allows adjusting the association controls a bit.

The waveforms, map and database buttons bring up dbpick, a location map, and dbe respectively. There are options under the right mousebutton for these buttons also.

OPTIONS

FILES

dbloc2 stores many intermediate files into a new directory tmp in the current directory. This directory should not be modified by the user.

ENVIRONMENT

see antelopeenv(5)

PARAMETER FILE

You may copy the dbloc2 parameter file into the directory where you are running dbloc2. This file has a number of sections; you should probably only modify the User section. Here are the parameters from that section:

The parameter file for dbml contains some station dependent information. To point the dbml program to a parameter file other than the default, modify the dbml line in this list to specify the correct file, eg "dbml -p knet".

Magnitude calculators should determine from the database whether they are appropriate for a particular origin, and only add to the database when they are. Any output the program makes to stderr appears in the scrolling one line status near the bottom of the screen.

SEE ALSO

antelopeenv(5)
dbpick(1), dbe(1), dblocsat2(1), dbgenloc(1)
warp(1)
dbloc2_location_if(3)

BUGS AND CAVEATS

AUTHOR

Daniel Quinlan

Table of Contents
Antelope Release 4.8 Darwin 8.7.0 2006-09-26
Boulder Real Time Technologies, Inc For more information, contact support@brtt.com