v2.9.7

Jump to:

• Basic Operation
• Map screen
• Select Events screen
• Select Networks screen
• Generate Request screen
• E-mail request screen
• DHI Seismogram Servers screen
• Bugs, Caveats and disclaimer
• Contact Information

     JWEED Tutorial - Flash Video  New

Description

JWEED is the Java version of our popular event-related request tool WEED. JWEED is a java program which can run on any platform which supports Java, Mac, Linux, Windows, Sun, etc.

Purpose

Using JWEED a person can obtain waveforms from any institution which has implemented DHI servers. As of this writing there are 4 institutions with servers, IRIS, Cal Berkeley, Cal Tech and South Carolina.

You can obtain data using JWEED with 5 basic steps:

• Select some servers
• Select some events
• Select some stations
• Specify arrival times for each station
• Download the data

Basic operation

When first invoked JWEED presents a screen with a scrolling list of servers. The servers are grouped by organization and within this grouping, by type. There are three types of servers, seismogram, event, and network/station metadata servers.

Here is an example "walk through":

Select a seismogram, network and event server from the servers screen.

Bring up the Map screen.

Using a mouse you can draw one or more bounding boxes. Once you have at least one bounding box click on the Select Events tab.

You can enter a variety of event parameters on which to base your query. Query for all (within the default time parameter) by clicking the Query DHI button.

[In the example below, the user set a parameter of 4.0 and greater magnitude events from the QED catalog]

This will fetch all events from the DHI event server that lie within the bounding box's latitudes and longitudes.  After the query returns you will get a listing. Click the Map Events button to apply these events to the map.

Similarly fetch all networks within the bounding box by going to the Select Networks tab and selecting the Query DHI button. You should see a listing of network/stations on the right part of the screen. The Cross Reference inputs are there to allow you to eliminate stations for which there are no waveforms available from the current waveform server. This is only an option.

Map these stations to apply the selection.

Since you now have some events and stations on the map, the next step is to generate a request. Clicking on the Generate Request tab will present a screen which allows you to specify start and stop times of waveforms at the selected stations arriving from the selected events. This is accomplished by selecting a starting phase and an ending phase. The calculated time of the starting phase and the ending phase, along with a bias before (-) or after (+) the calculated arrival, define the data collection window.

You then need to generate a request file, called a Summary File. Once you click on the Generate Summzry File button you will be asked for a file name. [See the Generate Request section for a description of the summary file.]

With the summary file created you can either mail in your request (E-mail Request Tab) or initiate the download process by clicking on the DHI Seismogram Servers tab.

If you email the request you will be notified seed volume is read to be picked up (usually via ftp). This is the only way to get a seed volume using JWEED.

Enter in the appropriate information. Toggle the desired organization and send it. You should see some confirming messages about the email successfully sent.

If you wish to download the waveforms directly, use The Seismogram Servers tab. With the summary file highlighted press the Retrieve Seismograms button. Messages will appear in the middle message window area detailing the download activity:

At this point each event's waveforms are listed by event in the scrolling list. You can select event individually or as a group for further processing.

Further processing includes viewing or saving to disk. If you wish to view the waveforms, each event's waveforms will appear in their own screen.

If you wish to save to disk each event's waveforms are saved in a directory based on the waveform server's name and under that, the event name.

Here is an example viewing:

When saving the waveforms to SAC, or when viewing sorted by distance, JWEED needs the extract from a network server the lat/lon position of the stations and/or the sensitivity of the instrument. You therefor must have selected a Network server from the servers list, or these buttons remain greyed (inactive).

This concludes the quick run-through.

Map Screen

Along the bottom of the map screen is the control panel. It is divided into functional areas. There are 4 map modes, lat/lon bounding box, point, select and free hand shape drawing. By positioning the cursor over each icon, JWEED will display hopefully helpful hints as to the functionality.

Lat/Lon bounding box mode: This is represented by the moving rectangle glyph. When in this mode you can draw any number of boxes on the map.

 

Point mode: This is represented by the crosshair glyph. Using this allows you to enter point or points on the map. These points can be used when making point->distance mappings.

 

Select mode: This is represented by the pointing finger. When in this mode it allows you to select individual boxes, shapes, stations, events, distance circles, for later processing such as removal, or printing station/event information when the Info screen is displayed.

 

Free hand shape drawing mode: This is represented by the free hand shape glyph. You can draw an arbitrary region using the free hand shape drawing mode. It is used the same as a bounding box. Once you have a shape drawn you can then query for events or stations which lie within the shape. You can also draw a shape around existing stations and events for removal from the map.

 

Lat/Lon Box: Use this entry for fine precision bounding box definition. Drawing bounding boxes rounds to the nearest integral latitude and longitude. If you require more precision, this is where you can achieve this.

 

Points: The "Points" entry is for fine precision latitude and longitude determination. You can enter points via a map mode but this point is rounded to the nearest integral latitude and longitude. If you require more precision you can enter point or points here.

 

Distance: Enter a minimum and/or maximum distance values. You can enter onto the map distance from points, events or stations. When you have some distances on the map you can, via the event or network screens, query for events/stations within this distance.

 

Remove: You can erase from the map all boxes, distance circles, shapes, events, stations or points by selecting the appropriate menu item and clicking the "Do it" button.

 

Undo: Similar to the "Remove" option except that you remove selected items. You can select one or more boxes, distance circles, shapes, events, or stations removing just the selected items using this function..

Select items by using the map select mode (pointing finger). When you click the "Undo" button, only the selected item is removed. You can also remove that last box or distance circle created.

 

Clear: This will clear the map; stations from box or shape, or events from box or shape;  Make a selection and click on the "Do it" button.

 

Info Screen: When you click on this button a new window will pop up. Information about mapped events and stations will be printed when you move the pointing hand over the token displayed on the map.

 

Zoom In/Out: You can magnify the image or make it smaller. As you zoom in it will eventually get blurry. As the map gets bigger it will eventually start to move off the screen. Use the scrollbars to move about the magnified image.

Select Events Screen

Starting/Ending Dates: Enter a starting and ending date for the event query. The default is today's date for the ending date and 30 days previous to this as the starting date.

 

Catalogs: These catalogs are retrieved from the event server at program startup. There is no default catalog. It is likely that you will get duplicate events unless you specify a catalog.

 

Magnitude Parameters: Enter a magnitude minimum and maximum. You can enter a floating-point number for magnitudes and depth.

 

Note that "Depth" min/max values are entered in this area.

 

Station->Event Parameters: If you have mapped some stations, you can find all events with an azimuth or back azimuth relative to these stations. You must have some stations queried for this to work, as it calculates events relative to these stations.

 

Query DHI: This will query the IRIS DMC's event server. A listing will appear matching the parameters as entered above and which fall into any boxes, distance circles or shapes as entered on the map.

 

Query Files: It is possible to work offline using local event files. You can get event files from IRIS DMC's ftp site: pub/jWEED/events, or the program can save event files to disk (see below). After choosing a file, a listing will appear matching the parameters as entered above and any boxes, distance circles or shapes as defined from the map.

 

Apply Local: After you have an event listing, you can further exclude events by altering the event parameters and clicking this button. For instance, if you have all events listed you could go back and modify the minimum magnitude value and after clicking this button this list will be updated.

 

Eliminating duplicate events by selecting a catalog and then clicking on this button is another useful function. JWEED will not re-query from the DHI but rather use the local set.

 

Map Events: After retrieving some events you can map all the listed events or selected subset. Events appear on the map as yellow circles.

 

Save Events: Use this button to save your events to disk.

 

Event listing: The events are listed in a selectable list. You can select one, multiple or none (all). How you make a selection varies with the operating system.

 

• Sun/Linux/Windows computers: <control><left mouse btn> to select multiple.
• Mac computers: <Apple><mouse btn> to select multiple

 

Deselect using the same sequence.

Select Networks Screen

Starting/ending dates: Enter a start/end date for the network query. By default it uses the date as entered in the Select Event Screen.

 

Event->Station Parameters: Entering in an azimuth or back azimuth will result in finding all stations lying with this range from events. You must have some events queried to use the function.

 

Channels: Click on the desired channels. You can select one or more.

• The PC/Linux/Sun computers use <cntrl><left btn> for multiple picks,
• The mac uses <APPLE><btn>.

 

Alternatively you can enter channels/locations in the appropriate scroll list. You can delimit with commas or whitespace, one or more to a line.

You can enter more than one per line, space delimited, or one per line.

 

Query DHI/Query Files: You can query the DHI server or any local disk files using these buttons. A tree-structured listing should appear to the right of the screen. In the listing are networks and stations which have met your criteria. You can click on a network name to see its stations. Clicking on the station name will result in this station's information to be printed in the Station Information area.

 

From this listing you can select one or many or none (all) for further mapping and/or processing.

 

Clear Detail: This clears the station information area.

 

Save Stations: You can save the listed stations to a local file.

 

Map Stations: By clicking this button the stations will be placed on the map. Stations are represented by red triangles.

Generate Request Screen

Time Window Parameters: The Generate Request Screen is used to specify a starting/ending time window for waveform extraction. To accomplish this you specify a Phase arrival of interest for the start of waveform extraction and for the end of waveform extraction.

 

There are entries for supplying a bias in seconds. Negative biases will be subtracted from the calculated arrivals.

Use Map / Listing for events/stations buttons: To generate a request you specify whether to use station/events from the map or the originating screen listing (the Select Events and Networks Screen). Most people will probably use the events/stations as mapped, but this is not a requirement.

 

Generate Summary File: When you click on this button jWEED will calculate the start/stop times and construct a summary file. Each event processed is appended onto the list.

 

A summary file is a text file used by JWEED as an intermediary format. JWEED will use the summary file to convert to BREQ_FAST /Net DC type request formats or the DHI server supported formats.

 

Being a text file, a summary file is easily viewable. Looking inside you will see each event listed. Underneath each event are the stations for which JWEED was able to calculate arrivals. Underneath this is a listing detailing the phase arrival time calculations.

 

Map Request: This will draw connecting lines from stations to events. If you have many events and stations in the same vicinity you might have better results if you pick individual events for mapping. You can select individual events for mapping by clicking on the event name in the listing.

 

Email Request Screen

After a summary file is generated you can use this screen to obtain a seed volume.  You email a request to IRIS using the BREQ_FAST mode or the NET_DC mode. Although some people might prefer to receive a chocolate sampler, the end result is a seed volume. You will be notified when your seed volume is ready. Pickup is by ftp.

 

You select a summary file; enter your name, email address and a seed label. Select either the BREQ_FAST or NET_DC request types. Make sure the email listing (Select where) is properly set. This email address entry is editable. There is no effort made to make sure a valid address is entered. You will want to send a BREQ_FAST request to breq_fast@iris.washington.edu and NETDC to netdc@iris.washington.edu. But there is nothing to stop you from entering another email address for whatever purpose you might want. Another institution which supports BREQ_FAST is Potsdam Data Center - the email address for BREQ_FAST requests is breq_fast@gfz-potsdam.de.

 

After emailing you will see some mailer messages appear in the listing. The last line should read: "Message accepted for delivery".

If you wish to keep a hard-copy version, click on the "Save to disk" button.

DHI Seismogram Servers

The DHI Seismogram Servers screen is divided into two pieces, the "Request Items" section and the "Waveforms" section.

 

Request Items:

 

Server types: There are two server types, online retrieval systems and the archive rerieval systems. As of this release (v2.3 Dec 10, 2004), IRIS is the only institution which has implemented an archival system.

A note about seismogram servers. As of this release this is what is known.

 

IRIS seismogram servers:

Bud Server: The Bud is the real-time streaming system. The Bud holds data from 2 weeks to 6 months. 2 weeks for high-speed networks, 6 months for others. Only a subset of networks from our holdings are in the Bud. If your request is for events within six months you could send it to the Bud.

 

Pond Server: The Pond is a repository for event-oriented data as listed in the NEIC and other sources; generally events with a magnitude of 5 and above. The Pond holds waveform events starting in 1990. Not all networks from our holdings are in the Pond. If your request is for major events after 1990, you could send it to the Pond.

 

Archive Server: The Archive is IRIS's main waveform repository. The Archive holds continuous and triggered data that has a latency of two weeks minimum to 6 months maximum.

If your request is for data older than 6 month you can try the Archive.

Berkeley servers:

The berkeley seismogram server runs two days behind. You can only download data up to 2 days from the present.

All other servers are more regular.

 

Retrieving data using the Online Systems:

Just click the button. Seismograms will be downloaded if they are available.

Retrieving data using the Archive: Requesting seismograms from the Archive is a three-step process, as it processes offline.

1. Queue the request. You will be asked for a name for this request. It sends the request of to be put into a queue. The name for the request is listed in the scroll area in the upper right.
2. Request Status: After selecting a request from the upper right hand scroll area, you can check its status by clicking on the "Request Status" button. If the status is finished you will get a smiley face. If it is not, a frown will appear. Messages to this effect will be printed out in the message area.
3. Retrieving Request from the Archive: Once you have a smiley face you can retrieve the request by clicking this button. Progress messages detailing how many seismograms for each event was retrieved.

Waveform section: As each event's data is retrieved a listing of these events is displayed in the "Seismogram" listing.

 

View: You can bring up a new window showing the waveforms for each event by clicking the "View" button. You can view events individually or all together (separate windows per event).

Be aware that if you view many events, depending on how many stations were reporting, you can run out of memory.

 

Save: You can save waveforms into disk files in either SAC or MINISEED format.

The user will be asked for an output directory. Under this directory, JWEED will create a directory for each event processed. JWEED will place all waveforms files for each event in the appropriate directory. These directories are named using the event date and time.

Bugs, Caveats and disclaimer

Contact Information