Maps and plots

All views follow the selection: selecting origins in the origin table highlights them on the map and in the plots, and the diagnostic plots always show the active origin.

Map panel

The Map panel. The views are tabs; the controls on the right are shared by all three views.

The panel has three Views - Map, Hexmap and 3D - and a column of controls on the right that applies to all of them:

Controls	Description
Animation	Steps through the origins in time order. Play starts or pauses the animation, the slider moves through it, Cumul. keeps the origins of earlier steps visible and Reset shows all origins again. The label next to Cumul. shows the time range currently shown.
Layers	Show or hide faults, symbols, the reference catalogue, cities, city labels, stations and station labels. Faults… loads faults (SeisComP XML or GeoJSON lines), which are also used for the Fault Q metric; Catalog… loads an external reference catalogue (FDSNWS text or CSV with time,lat,lon,depth), drawn as grey dots. The Reset next to each removes it again.
Clustering	Clustering of the origins shown: eps (neighbourhood radius), min size (minimum cluster size) and depth × (weight of depth in the distance). auto lets catalyst choose. Press Refresh to cluster again. Changing a parameter does not recluster on its own; the button changes to Refresh * until it is pressed.
Cluster legend	One entry per cluster with its colour and number of origins. all and none show or hide every cluster, the checkbox of an entry shows or hides that cluster. The list scrolls when there are many clusters.

The reference cities come from the key gui.cities, in the profile or in catalyst.cfg.

Map

The Map tab shows the origins, the stations and the picks. The active origin is the large star; lines connect it to its stations, whose triangles are coloured by the residual of their pick (red late, blue early, grey unused). Picks are drawn at their stations. Clicking a pick selects the origins it belongs to, and clicking a star selects that origin. Hover over a station to see its name, phase and residual.

Hexmap

The Hexmap view: number of events per hexagon, all times of day.

The Hexmap tab shows the origins as a hexagon density map. The settings are in the box in the upper right corner of the map:

Setting	Description
Cell value	What the Cells show; the arrows step through the values (see below).
Colour scale	Colours of the cell values, from the lowest to the highest value shown.
Res	Width of a hexagon in km.
Symbols	Overlays the epicentres and stations.
Time category	Limits the cells to the origins of one time category (see below); all uses every origin.
Min count	Hides cells with fewer origins than this.

Each cell can show

• the number of events,

• the mean depth,

• the mean number of phases,

• the difference in the number of events between the catalogue and a loaded reference catalogue.

The time categories are day or night (sun above or below the horizon at the epicentre), weekday or weekend (local date), summer (June to August) and winter. Comparing day and night or weekday and weekend maps helps to find quarry blasts and other man-made sources. A note on the map explains when a category contains no origins.

3D

The 3D view: hypocentres coloured by cluster above the topography.

The 3D tab shows the hypocentres in three dimensions.

• Topography is drawn as a surface if gui.demPath is set, coloured by elevation, on the same scale as the depth, with the sea floor at sea level. Faults, cities and stations sit on the ground.

• Clusters: each hypocentre is coloured by its cluster; origins that do not belong to any cluster are grey. The clustering is set with the Clustering controls on the right and shown or hidden per cluster in the Cluster legend (see above).

• Faults and the reference catalogue are switched on in Layers.

Picks panel

Tab	Content
Table	All picks, sortable by every column. The context menu offers Copy, Save as CSV… and Delete pick(s).
Histogram	Number of picks over time. Click a bar to show only its picks; see Pick filters.
Map	The stations with their picks on a map. See below.
Beams	Array beams on a map: the back-azimuth of each array pick drawn from its station.
Slow/Baz	Slowness against back-azimuth of the array picks as a polar chart; selecting segments filters the picks. See below.
Baz/time	Back-azimuth of the array picks over time. Sources that are active repeatedly show up as horizontal lines.

The Beams and Slow/Baz tabs show the picks of the selected origins when origins are selected.

Pick map

Pick map: unassociated picks per station.

Each station with picks is a diamond. Its size and colour (yellow to red) grow with the value shown; large values are written on it. Click the legend in the upper right corner to switch the value:

Value	Meaning
unassociated count	Picks of the station that belong to no origin.
overdetection	Unassociated picks per associated pick. A station far above the others picks noise; its picks are weak evidence (see Clean Q in Quality metrics).

Slow/Baz

The Slow/Baz chart of an infrasound data set: all picks lie on the Is band.

The chart shows each array pick at its back-azimuth (angle, north up, clockwise) and its horizontal slowness (radius, logarithmic). The pick colour identifies the station; picks hidden by a filter are drawn grey.

The radius is divided into rings whose limits are written along the top edge in s/° and as trace velocity in km/s:

• the inner rings hold seismic picks (fast, below about 30 s/°),

• the Is band holds atmospheric infrasound, 0.30–0.45 km/s trace velocity (about 247–371 s/°, after the European Infrasound Bulletin [3]),

• the outer ring holds slower detections, usually wind noise.

Each ring is cut into 15° sectors. The mouse actions are shown at the bottom of the chart:

• click a sector to select or deselect it,

• Shift+click selects or deselects a whole ring,

• right-click the Is band to change its limits.

Selected sectors act as a pick filter: only array picks inside them stay visible in the table and the other views, and only those are used for nucleation. Picks without a back-azimuth or slowness are not affected. The selection and the band limits appear in the pick filter dialog and are saved in the profile (picks.traceVelocity.min, picks.traceVelocity.max).

Baz/time

Back-azimuth over time. Repeating sources form horizontal bands.

The plot shows the back-azimuth of each array pick against its time. Only the picks visible in the pick table are drawn, so the pick filter and the Slow/Baz selection apply. Each station has its own colour, and the marker shape follows the phase (circle P, square S, triangle Is).

A source that is active repeatedly - a quarry, a mine, a test site - is seen from one array under nearly the same back-azimuth every time, so its picks line up as repeating sources: horizontal bands. A band that appears in several arrays at once points to the source; Match Slow/Baz (see Refining origins) uses this.

The summary in the upper left counts the picks and stations shown and the picks selected. Drag a rectangle to select its picks in the pick table (with Shift to add, Ctrl to remove); selected picks get a dark ring. Hover a marker to see its station, phase and time.

Origins panel

Tab	Content
Table	The events and their origins with their quality metrics, see Events and origins and Quality metrics. The filter button opens the origin filters: latitude, longitude, depth, RMS, phase count, mismatch, status and whether the origin was updated.
Cumulative	Cumulative number of origins over time, for all origins and for the classes with at most 5, 10, 20 and 40 phases. The header counts the origins per class. A class that grows in steps points to bursts of small events or of false origins.
Wadati	Wadati diagram of the selected origins. See below.

Cumulative number of origins over one week, for all origins and per phase-count class.

Events and origins

The origin table: events with their preferred origin, one event expanded.

The table is a tree. Each event is one row, showing its preferred origin; expand it to see all origins of the event. Origins that belong to no event are plain rows. The colour symbol of a preferred origin is a star; a gold star marks a starred origin.

Sorting applies on both levels: events are ordered by their preferred origin, the origins of an event among themselves. Sorting by RMS, for example, orders the events by the RMS of their preferred origin.

The first columns follow the FDSNWS event text format: EventID, Time, Latitude, Longitude, Depth/km, Author, Contributor, MagType, Magnitude, MagAuthor, EventLocationName and EventType. To save room the headers show short labels (Lat, Lon, Depth, Contrib, MType, Mag, MAuthor, Region, Type); the tooltip and the CSV export use the full names. Next to EventType, Type certainty (short Cert.) tells how sure the type is: known or suspected, the values of the SeisComP event attribute typeCertainty. Location quality, state, provenance and the computed QC columns follow.

Right-click an origin and choose Set event type to classify it. The type is stored as an origin comment (deepc:eventTypeHint) and its certainty as a second one (EventTypeCertainty); both are sent with the origin and kept when it is relocated. Classifying sets the certainty by rule: suspected for preliminary origins and for origins found by a swarm or repeat search (methods swarm-consensus, fingerprint-match, template-match), known for all others. Set type certainty changes it by hand.

The RMS column shows the locator’s RMS for located origins. For preliminary origins, and origins whose location failed, it is computed from the travel-time table.

Right-click the header to show or hide columns. Columns can be dragged to a new position. The shown columns and their order are stored in the profile (gui.columns.origins), likewise for the pick and arrival tables (gui.columns.picks, gui.columns.arrivals). Computed QC columns are hidden by default and appear by themselves once their values are calculated, for example Score after Calculate score or Arch [dB], Arch n and Post [dB] after Calculate spectra.

Wadati

Wadati diagram of one origin in the Aleutians, Vp/Vs = 1.74.

The Wadati tab plots, for every station with both a P and an S pick, the S−P time against the P time after the first P of the origin. All station pairs of the selected origins go into one diagram. The red fit line gives the Vp/Vs ratio (slope + 1), shown in the upper left corner together with the number of origins.

Points far off the line point to a mispicked P or S, or to an S associated with the wrong origin.

Active origin panel

The plots of the active origin are the main tool for judging a location. All plots, the arrivals table and the pick plots draw a pick the same way: the shape gives the phase family, the colour its state.

Shape	Phase family
circle	P
square	S
triangle	Is (infrasound)

Fill / outline	State
red / red	used by the origin
white / red	associated, not used (weight 0)
blue / red	to be added (pending)
red / blue	to be removed (pending)
blue / blue	not associated

A weight-0 arrival that is switched on again is shown as to be added until the next relocation.

Double-click a marker to switch its pick on or off. Box selections work the same in all plots:

Mouse	Action
drag	keep the picks inside the box (unassociated ones are added), take the used ones outside out
Shift+drag	add / switch on the picks inside the box
Ctrl+drag	take the picks inside the box out

Arrivals at weight 0 that the locator still flags as time-used are treated as used, so a box takes them out as well. Right-click a marker and choose Rename phase… to give the pick another phase (for example pP or S); a loose pick is added to the origin with that phase. Hover a marker to see its station, phase and time.

Tab	Content
Arrivals	The arrivals with residual, distance, azimuth and weight. Right-click selected rows and choose Rename phase… to change their phase.
Distance	Residual against distance.
Azimuth	Residual against azimuth. A trend with azimuth points to a mislocation.
Baz residual	For array picks: measured minus predicted back-azimuth against azimuth, with the pick uncertainty as error bars.
Travel-time	Picks against distance with the P and S travel-time curves and their tolerance bands. This is the plot the analyst rules are based on.
Move-out	Reduced travel time (T − d/V) against distance per phase family, with the apparent-velocity fit. See below.
Polar	Plan view of the stations around the epicentre. The azimuthal gap is easiest to see here.
Spectra	Is it a real event? For the nearest stations, the spectrum of the P window (left) and of the S window (right) is compared with the noise before P; a real event lifts both and forms an arch. For infrasound the Is window of the pressure channel replaces S. Shown when the profile sets spectra.enabled = true. The results also feed the QC fields, see Spectra.
Infrasound	Do the array picks fit this origin? One row per array with celerity, back-azimuth residual, apparent velocity, the seasonal wind and a verdict. Shown when the profile sets infra.enabled = true. See Infrasound.

Baz residual

Back-azimuth residuals of three array picks, all within the tolerance.

For each array pick of the active origin the plot shows the residual - the measured back-azimuth minus the direction from the station to the epicentre - against the azimuth of the station seen from the epicentre. The error bars are the back-azimuth uncertainty of the pick (asymmetric if the pick has a lower and upper uncertainty).

The green tolerance band is ± Az tol of the back projection (see Back projection). Picks inside it agree with the epicentre. A single array far outside points to a wrong association or a disturbed bearing; the Azimuth locator switches such an array off by itself when three or more arrays are available. A trend with azimuth points to a mislocation. If no arrival carries a back-azimuth, the plot says so.

Infrasound

The tab answers one question for an infrasound origin: do the array picks fit it? Only the pick values are used (time, back-azimuth, slowness and their uncertainties from Lambda / autolambda), no waveforms. The tab is shown when the profile sets infra.enabled = true; the infra profile does.

For every array within infra.maxDistance the tab lists the best pick between 0.20 and 0.40 km/s celerity, associated or not, and every arrival of the origin whatever its celerity. Each pick is tested three ways:

Test	Passes when
Celerity	Distance / (pick time − origin time), widened by the time uncertainty, lies in the band infra.celerity and within ± infra.celSpread of the reference celerity, the median of the arrays that fit on direction and speed. One event has one celerity, so an array far off the others points to another source.
Direction	|measured − predicted back-azimuth| ≤ max(Az tol of the back projection, infra.bazNSigma × the pick’s uncertainty). This is the same gate Associate uses.
Speed	Apparent velocity 111.19 / slowness lies in infra.appVel (0.30–0.45 km/s): acoustic, not seismic or wind noise.

Column	Content
Use	Whether the pick is an active arrival, as in the Arrivals tab. Click to add a fitting pick or remove one that does not fit (pending until Relocate).
Array	The reference station of the array: the station its picks carry (with infra.arrays / infra.arraysConfig the one with the most picks; without picks the first element).
Dist [km]	Distance from the origin to the array centre.
Wind	Seasonal stratospheric ducting: westward in the northern summer (May–Aug), eastward in winter (Nov–Feb). An upwind array is not expected to see the event and is left out of Is frac unless it confirms. Empty in the transition months and in the tropics; infra.seasonal = false switches the rule off.
Cel [km/s]	Celerity, green when the celerity test passes.
Baz obs / Baz pred / Res [°]	Measured and predicted back-azimuth and their difference, with the tolerance.
App vel [km/s]	Apparent velocity of the pick.
Verdict	confirms, wrong direction, not acoustic (speed), time mismatch (in the band, but off the other arrays), outside window (celerity outside the band) or no pick.

An array confirms when one of its picks passes all three tests. The counts feed the QC fields Is n, Is frac and Is baz, see Infrasound. Selecting a row selects the pick in the other views.

Reading the tab. Two confirming arrays fix a location by their crossing bearings; three or more confirm it. A wrong direction at one array among several confirming ones usually means a second source or a crosswind deflection (up to about 10° [3]). Time mismatch at a single array usually means a different propagation path (for example a thermospheric return at 0.22–0.26 km/s next to stratospheric ones at 0.28–0.31 km/s); at several arrays the origin time or location is off, so relocate first.

Arrays are defined in two ways:

• Automatic (infra.arrays empty): every station whose picks carry a back-azimuth on a pressure channel (?D?) or with phase Is counts as one array.

• From the Lambda configuration: name the arrays and point infra.arraysConfig at the files that define them; the elements are grouped and the array centre is the mean element position:

  infra.arrays = BURARI, IPLOR, ROMANIA_RO, LISA
  infra.arraysConfig = @SYSTEMCONFIGDIR@/autolambda.cfg
  

Spectra

Spectra of the five nearest stations of an origin: all show an event.

The plot compares, for the nearest stations with an arrival in the origin (one per station, picked or weighted 0 by the locator), the spectrum of the P window (left, frequency increasing to the left) and of the S window (right, frequency increasing to the right) with the spectrum of the noise before P (dotted). A real event lifts both windows above the noise and the curves form an arch over the middle line.

The table lists per station the distance, S−P time, the height of the P and S spectra above the noise, the Arch - the lower of the two, in dB - and Post, the level of the window after S. A station whose arch is above the Threshold counts as event. A high Post means another event follows in the window. With scan ± the windows are shifted by up to the given time to find the best fit, which absorbs small errors of the location. The summary at the bottom right counts the stations with an event.

Stations sets how many of the nearest stations are evaluated and within the largest epicentral distance (no limit = 0). Both start with the profile values spectra.stations and spectra.maxDistance and are saved with Save as…. Raising them loads only the waveforms of the stations that are new; the ones already loaded are kept for the shown origin, so a few noisy stations can be outvoted without reloading everything. Lowering them needs no new data. Calculate spectra in the QC tab uses the same values.

Arch [dB], Arch n and Post [dB] are also QC fields and columns of the origin table, see Spectra.

Infrasound. A station with an Is arrival is evaluated on its pressure channel (?DF, for example HDF or BDF): the Is window takes the place of S on the right side. It starts spectra.isLead s (default 5) before the Is pick and is spectra.isLength s (default 30) long; the noise window of the same length ends before the earliest arrival at the station. Its height is averaged over the Is band only (spectra.isBand, default 1–10 Hz), so microbaroms and wind below 1 Hz do not dilute it.

The station has	Left half	Right half	Arch
P and S	P (vertical)	S (vertical)	min(P, S)
P and Is, for example a Raspberry Shake & Boom (00.EHZ and 00.HDF)	P (vertical)	Is (pressure)	min(P, Is)
only Is (infrasound array or station)	empty	Is (pressure)	Is

With Is on the right, the P window is at most spectra.pMaxIs s (default 30) long and ends before the Is pick; the S−P column shows Is − P.

Arrays are one row, NET.STA (n): the reference station (the station of the Is pick) and the number n of elements, when the profile defines them (infra.arrays and infra.arraysConfig, see Infrasound). Every element is evaluated; an element more than spectra.suspect dB (default 6) below the upper half of the elements is suspect - a dead, disconnected or noisy element - and the row turns orange. The array value is the median of the other elements, so even a majority of dead elements does not pull it down. Hover the station cell for the value of each element. An array counts once in Arch n and in the median, not once per element.

Infrasound arrival times vary by tens of seconds with the propagation, so the Is window starts at the pick, not at a predicted time, and is not shifted by the scan. Coherent array processing (PMCC) detects arrivals below the amplitude threshold of this test: a weak arrival found by Lambda may still show only 1–3 dB here.

Move-out

Move-out of an infrasound origin: three Is picks, the fitted line and the celerity band.

The move-out plot shows the reduced travel time T − d/V of the picks against distance. With V equal to the apparent velocity of the picks they line up horizontally, which makes outliers and wrong phases easy to see.

The controls select the phase Family (P, S or Is), set Reduce vel (V) and run Fit V. Fit V fits a straight line through the used picks of each family and writes the result to the fit readout: the apparent velocity with its uncertainty, the RMS and the number of picks. The selected family’s velocity becomes Reduce vel, and its fit line is drawn dashed, labelled with V and t0 - the time of the line at distance 0 relative to the origin time. A t0 far from 0 means the origin time does not fit the picks.

For P and S the theoretical travel-time curves of the selected model are drawn. For Is the celerity band is drawn instead: a wedge from the origin between 0.27 and 0.34 km/s celerity. Picks inside it are consistent with stratospheric or tropospheric propagation.

Why the move-out is not a straight line

A straight line in the move-out plot means one constant apparent velocity. The first P arrival does not have one: with distance it travels along different paths, each faster than the one before. Reduced with V = 8.4 km/s, typical for regional P, the picks of a good event therefore form a bent curve, not a line:

Distance	First arrival	Apparent velocity	Curve with V = 8.4 km/s
near the source	Pg, through the crust	about 6 km/s	rises steeply: slower than V
from about 150-250 km	Pn, along the Moho	about 8 km/s	almost flat, rises slowly
from about 1500-2000 km	rays through the upper mantle, whose velocity grows with depth; the 410 and 660 km discontinuities
9-11 km/s	bends down: faster than V

Other effects bend it as well:

• Depth. Close to a deep source the rays come up steeply: the travel time hardly grows with epicentral distance, the curve starts flat or even falls before it rises.

• Crossover distance. Where Pg and Pn swap depends on the thickness of the crust and on the source depth, so the kink moves from event to event.

• Mislocation. A wrong epicentre gives wrong distances, the curve then scatters or bends on one side.

The theoretical curves of the travel-time model in the plot follow these branches; the picks should follow the curve, not a straight line. A fit line (Fit V, Keep line) is only valid along one branch: for P use the distances where Pn is the first arrival, for local events the Pg range.

Move-out after Keep line (P, 5.5–8.5 km/s, band 2 s): 95 of 171 P picks lie on the line. The S picks are another family and stay. Beyond about 2000 km the P branch bends away from a straight line, so these picks are taken out as well - check before relocating, or widen the band.

Keep line cleans an origin that mixes the picks of two events. Set the velocity range (V, from–to) and the band [s] and press Keep line: catalyst finds the straight line, with an apparent velocity in the range, that the most picks of the selected family lie on, draws it, and marks the picks of that family farther than the band from it as to be removed. The larger event wins rather than a compromise between the two. Relocate afterwards. A straight line does not follow the bend between Pg and Pn; widen the band for picks over many hundred kilometres. The range follows the family: P 5.5–8.5, S 3.0–5.0, Is 0.25–0.40 km/s.

Travel-time

Travel time of a regional event against distance: the used picks on the P and S curves, the crustal branches near the source and unassociated picks in blue.

The plot shows the travel time of each pick (pick time minus origin time) against the epicentral distance. The curves are the travel times of the selected model for the phases of the picks - P, S and their crustal branches, or the Is curve for infrasound. Beyond regional distances the depth, reflected and core phases (pP, sP, PcP, ScS, PP, SS, PKPdf) are drawn as well, when the travel-time table provides them (libtau does, LOCSAT’s tables mostly do not). The shaded tolerance band around each curve is ± Assoc. tol: picks inside it are associated by Associate and kept by Deassociate.

Picks of the origin are drawn in their state colour; unassociated picks nearby are blue and can be selected with a rectangle and associated. This is the plot the analyst rules are based on.