West Coast/Alaska Tsunami
Warning Center
Operations Manual
NOAA/NWS/WCATWC
Palmer,
http://wcatwc.arh.noaa.gov
Section
4.1.9 – lpproc
Last
Updated: 9/2010
Date
Written: 4/2001
Development Language: MicroSoft C/C++ v7.0 using WinAPI
Necessary Rings:
Input Ring - WAVE_RING_LP; reads TYPE_TRACEBUF format messages
Input
Ring - HYPO_RING; reads TYPE_HYPOTWC format messages
Output
Ring - PICK_RING; writes TYPE_PICKTWC format messages (with
MS parameters)
Output Ring - ALARM_RING; writes TYPE_ALARM format messages
Necessary Data Files:
StaFile
– lpproc configuration file
StaDataFile - seismometer location, elevation, etc.
ResponseFile - Broadband instrument response in poles/zeroes format
DummyFile - Hypo-parameters
of last located quake
LPRTFile - MS data computed for last quake
QuakeFile - List of
automatically located quakes
Initialization File:
lpproc.d - read on module start-up
Module Description:
This module takes long period waveforms from the
WAVE_RING and displays them on a window. The display is similar to an old-style
develocorder (with no film delay). Every X seconds the screen scrolls to the
left. The most recent data are shown on the right of the screen. The display
can be "held" and manually scrolled through previous times (the time
limit of saved data is specified in the .d file). Traces can be scaled and sorted by menu
options or accelerator keys.
Hypocenters entered to HYPO_RING are obtained by this module. When an analyst
selects the RT LP push button in Locate, this module will compute expected
Rayleigh wave times at stations listed in StaFile and will evaluate the data in
the window for Ms for up to 30 minutes past the expected Rayleigh wave arrival
time. When an Ms is computed, the data are sent in the TYPE_PICKTWC message
format to PICK_RING with P-time=0 and the magnitude is displayed on the lpproc
screen.
As data are read from the WAVE_RING, it can be processed by an LP alarm with
parameters specified in the initialization file and the StaFile. If a large
signal is found by the alarm function, an alarm is reported to ALARM_RING.
NOTE: A semaphore is accessed in lpproc so that LP processing can be triggered
by program Locate. This semaphore should not prevent the program from working
if Locate is not running.
Program Controls:
This module has a Windows graphical
interface. Due to this interface, the module will only compile and run
under Windows (NT, 2K, or XP). The display shows real-time, long period data.
The most recent time is shown on the right side of the screen. As new data
arrives, the screen scrolls left. A "Hold Screen" menu option is available
to stop the automatic scrolling. Then, the horizontal scroll bars can be used
to manually scroll through all the data which is in memory.
Surface wave data processing is triggered interactively through a push button
in Locate or automatically through loc_wcatwc output. Computed MS is shown near
the trace name and an average is shown in the title bar. The MS processing can
be started or stopped manually through the magnitude menu option. As magnitudes
are computed, the expected Rayleigh wave start time is displayed on each trace,
and the cycle which is used to compute MS is marked with a plus sign.
Mouse Buttons:
Right button on trace toggles trace
display.
Right button on station name calls station manipulation menu (for trace scaling, trace
display on/off, alarm on/off).
Menu
Options:
Hold Screen: Prevent automatic
scrolling so that scroll bars can be used to move through data.
Horizontal Scale: Change screen time scale.
Vertical Trace Scale - All: Change vertical scale for all
stations.
Traces Per Screen: Number of traces vertically to show
on the screen, rest will scroll.
Show Channel: Display channel name to right of
Station Name.
Show Network: Display Network ID to right of Station
Name.
Show Epicentral Distance: Display Epicentral distance from
last quake right of Station Name.
Display Filtered Data: Check -> screen shows LP filtered
signal for broadband stations.
Display Broadband Data: Check -> screen shows unfiltered
traces for all stations.
Magnitude:
Compute
Ms: Using last
location in dummy file, process LP data for MS. After processing, a plus sign is marked on the cycle used to compute MS.
Stop Processing: Stop ongoing computations (usually
used when automatic location has been updated).
Sort:
Alphabetical: Order stations on screen in
alphabetical order
Network: Order stations on screen by Network
Distance: Order stations on screen by distance
from last quake
Geographical: Order stations on screen by
original, geographic order (default)
Find: Enter station code to center on screen
ClipIt: Limit trace amplitudes.
Refresh: Re-paint the screen
Accelerator
Keys:
Arrow Up: Show more traces on screen.
Arrow Down: Show less traces on screen.
Arrow Right: Increase horizontal scale.
Arrow Left: Decrease horizontal scale.
Page Up: Increase vertical scale.
Page Down: Decrease vertical scale.
B: Show broadband data.
F: Find station.
N: Display Network code.
R: Reset all options to default.
S: Display filtered data.
F5: Sort alphabetically
F6: Sort by Network
F7: Sort by Distance
F8: Sort by Original Order (geographic)