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NESN



A STUDY OF NEW ENGLAND SEISMICITY

Quarterly Earthquake Report



July-September, 2004



New England

Seismic Network



Weston Observatory

381 Concord Road

Weston, MA 02493





NEW ENGLAND SEISMIC NETWORK

John E. Ebel, Principal Investigator

Weston Observatory

Dept. of Geology and Geophysics

Boston College

381 Concord Road

Weston, MA 02493

Email: ebel@bc.edu

Award # 04HQAG0020

Prepared by Anastasia Macherides Moulis

Email: macherid@bc.edu

October 1, 2004

for

United States Geological Survey

905 National Center

12201 Sunrise Valley Drive

Reston, Virginia 20192

Notice

Network operation supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award number 04HQAG0020. The views and conclusions contained in this document are those of the authors andshould not be interpreted as necessarily representing the official policies,either expressed or implied, of the U.S. Government.

Quarterly Earthquake Report

July-September, 2004

Table of Contents

Introduction

The New England Seismic Network (NESN) is operated by the Weston Observatory (WES) of Boston College. The mission of the NESN is to operate and maintain a regional seismic network with digital recording of seismic ground motions for the following purposes: 1) to determine the location and magnitude of earthquakes in and adjacent to New England and report felt events to public safety agencies, 2) to define the crust and upper mantle structure ofthe northeastern United States, 3) to derive the source parameters of New England earthquakes, and 4) to estimate the seismic hazard in the area.

This report summarizes the work of the NESN for the period July-September, 2004. It includes a brief summary of the network's equipment and operation, and a short discussion of data management procedures. A list of participating personnel is given in Table 1. There were 3 earthquakes that occurred within or near the network during this reporting period. Phase information for these earthquakes is included in this report.

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Current Network Operation and Status

The New England Seismic Network of Weston Observatory of Boston College currently consists of 11 broadband three-component and 8 analog strong-motion stations. The coordinates of the stations are given in Table 2, and maps of the weak- and strong-motion networks are shown in Figures 1 and 2, respectively. The 11 stations consist of Guralp CMG-40T three-component sensors. Ground motions recorded by these sensors are digitized at 100 sps with 16-bit resolution. Additional gain-ranging provides 126 dB dynamic range. These stations are operated in dialup mode with waveform segments of suspected events transmitted in digital mode to Weston Observatory for analysis and archiving. WES also maintains 8 SMA-1 strong-motion instruments in New England.

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Seismicity

There were 3 earthquakes that occurred in or adjacent to the NESN during this reporting period. A summary of the location data is given in Table 3. Figure 3 shows the locations of these events. Figure 4 shows the locations of all events since the beginning of network operation in October, 1975.

Table 4 gives the station phase data and detailed hypocenter data for each event listed in Table 3. In addition to NESN data, arrival time and magnitude data sometimes are contributed for seismic stations operated by the Geological Survey of Canada (GSC), the Lamont-Doherty Cooperative Seismographic Network, and the US National Seismic Network. Final locations for this section were computed using the program HYPO78. For regional events (those too far from the NESN to obtain accurate locations and magnitudes) phase data are given for NESN stations, but the entry in Table 3 lists the hypocenter and geographic location information adopted from the authoritative network. Accordingly, the epicenter is plotted on the maps using the entry from Table 3.

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Data Management

Recent event locations are available at http://aki.bc.edu/cgi-bin/NESN/recent_events.pl. Waveform data are saved in Nanometrics, ASCII, and SEED formats and are available by contacting, Anastasia Macherides Moulis, via email. Earthquake lists can be found at www.bc.edu/research/westonobservatory/northeast/eqcatalogs/. Currently available on the Weston Observatory web page is the full catalog of northeastern U.S. earthquake activity to the present time. This will be updated as new Northeastern U.S. Seismic Network Quarterly Earthquake Reports are produced.

For more information on matters discussed in this report or general earthquake information (reports, maps, catalogs, etc.) consult our web site www.bc.edu/westonobservatory or contact:





Anastasia Macherides Moulis

Weston Observatory

381 Concord Road

Weston, MA 02493

Voice: 617-552-8325 / FAX: 617-552-8388 / Email: anastasia.macherides.1@bc.edu



Dina Smith

Weston Observatory

381 Concord Road

Weston, MA 02493

Voice: 617-552-8335 / FAX: 617-552-8388 / Email: dina.smith.1@bc.edu



Prof. John Ebel

Weston Observatory

381 Concord Road

Weston, MA 02493

Voice: 617-552-8319 / FAX: 617-552-8388 / Email: ebel@bc.edu

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Explanation of Tables

Table 1: List of personnel operating the NESN

Table 2: List of Seismic and Strong Motion Stations

  1. Code = st ation name
  2. Lat = station latitude, degrees north
  3. Long = station longitude, degrees west
  4. Elev = station elevation in meters
  5. Location = geographic location
  6. Operator = network operator

Table 3: Earthquake Hypocenter List

  1. D ate = date event occurred, Yr (year)/Mo (month)/Dy (day)
  2. Time = origin time of event, Hr (hour):Mn (minute):Sec (second)

    in UCT (Universal Coordinated Time, same as Greenwich Mean Time)
  3. Lat = event location, latitude north in degrees
  4. Long = event location, longitude west in degrees
  5. Depth = event depth in kilometers
  6. Mag = event magnitude
  7. Int = event epicentral intensity
  8. Location = event geographic location

Table 4: Earthquake detailed hypocenter and phase data list

Table Header: detailed hypocenter data

  1. Geographic location
  2. DATE = date event occurred, yr/mo/dy (year/month/day)
  3. ORIGIN = event origin time (UCT) in hours, minutes, and seconds
  4. LAT N = latitude north in degrees and minutes
  5. LONG W = longitude west in degrees and minutes
  6. DEPTH = event depth in kilometers
  7. MN = Nuttli Lg phase magnitude with amplitude divided by period
  8. MC = signal duration (coda) magnitude
    WES: 2.23 Log(FMP) + 0.12Log(Dist) - 2.36 (Rosario, 1979 )
    MIT: 2.21 Log(FMP) - 1.7 (Chaplin et al., 1980)
  9. ML = local magnitude
    WES: calculated from Wood-Anderson seismograms (Ebel, 1982)
    GSC (Geological Survey of Canada): Richter Lg magnitude
  10. GAP = largest azimuthal se paration, in degrees, between stations
  11. RMS = root mean square error of travel time residual in seconds
  12. ERH = standard error of epicenter in kilometers
  13. ERZ = standard error of event depth in kilometers
  14. Q = solution quality of hypocenter
    A = excellent
    B = good
    C = fair
    D = poor

Table Body: earthquake phase data

  1. STN = station name
  2. DIST = epicentral distance in kilometers
  3. AZM = azimuthal angle in degrees measured clockwise between true north and vector pointing from epicenter to station
  4. Description of onset of phase arrival
    I = impulsive
    E = emergent
  5. R = phase
    P = first P arrival
    S = first S arrival
  6. M = first motion direction of phase arr ival
    U = up or compression
    D = down or dilatation
  7. K = weight of arrival
    0 = full weight (1.0)
    1 = 0.75 weight
    2 = 0.50 weight
    3 = 0.25 weight
    4 = no weight (0.0)
  8. HRMN = hour and minute of phase arriva l
  9. SEC = second of phase arrival
  10. TCAL = calculated travel time of phase in seconds
  11. RES = travel time residual (error) of phase arrival
  12. WT = weight of phase used in hypocentral solution
  13. AMX = peak-to-peak ground motion, in millimicrons, of the maximum envelope amplitude of vertical-component signal, corrected for system response
  14. PRX = period in seconds of the signal from which amplitude was measured
  15. XMAG = Nuttli magnitude recorded at station
  16. FMP = sign al duration (coda), in seconds, measured from first P arrival
  17. FMAG = coda magnitude recorded at station

Table 5: Microearthquakes and other non-locatable events

  1. Date = date event occurred, Yr (year)/Mo (month)/Dy (day)
  2. Sta = neares t station recording event
  3. Arrival Time = phase arrival time, Hr (hour):Mn (minute):Sec (second)

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TABLE 1



WESTON OBSERVATORY PERSONNEL

Name Network Position voice phone email address
John E. Ebel Principal Investigator 617-552-8319 ebel@bc.edu
Alan Kafka Research Seismologist 617-552-8300 kafka@bc.edu
Anastasia Macherides Moulis Seismic Analyst 617-552-8325 macherid@bc.edu
vacant NESN Operator 617-552-8332 @bc.edu
Dina Smith Associate Director of Scientific

and Technical Operations
617-552-8335 dina.smith.1@bc.edu
Weston Observatory
617-552-8300

617-552-8388 (FAX)



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TABLE 2




     

SEISMIC STATIONS OF THE NEW ENGLAND SEISMIC NETWORK

WES43.7050-72.3525Belchertown, MATroy, NYWESUMMWES42.3850WESYLEPQI46.6710
Code Lat Long Elev (m) Location Operator
BCX 42.3350 -71.1705 61.0 Chestnut Hill, MA WES
BRYW 41.9178 -71.5388 380.0 Smithfield, RI WES
FFD 43.4702 -71.6533 131.0 Franklin Falls Dam, NH
HNH -72.2860 180.0 Hanover, NH WES
QUA2 42.2789 168.0 WES
TRY * 42.7311 -73.6669 131.0
44.7100 -67.4583 35.0 Machias, ME WES
VT1 44.3317 -72.7536 410.0 Waterbury, VT WES
-71.3220 60.0 Weston, MA WES
WVL 44.5648 -69.6575 85.0 Waterville, ME
41.3100 -72.9269 10.0 New Haven, CT WES
-68.0168 175.0 Presque Isle, ME WES

* = not in operation during this quarter


     

STRONG MOTION STATIONS OF THE NEW ENGLAND SEISMIC NETWORK

SM2-73.10Newport, RISM4-71.30WESSM742.39-71.54WES
Code Lat Long Location Operator
SM1 44.90 -67.25 Dennysville, ME WES
44.49 Essex Junction, VT WES
SM3 41.45 -71.33 WES
42.38 -71.32 Weston, MA WES
SM5 42.66 Lowell, MA
SM6 42.30 -71.34 Natick, MA WES
Huds on, MA WES
SM8 44.48 -69.61 North Vassalboro, ME


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TABLE 3




     

EVENTS IN NEW ENGLAND AND ADJACENT REGIONS


Date

M/D/Y
Time (UTC)

Hr:Mn:Sec
Lat Long Depth

(km)
Mag Int Location
08/04/2004 23:55:27.02 43.71 -78.24 5.00 3.8*
ON, OFFSHORE, 30KM S OF PORT HOPE
08/28/2004 12:38:37.92 43.16 -71.61 5.00 2.4
NH, 9KM SSW OF CONCORD
09/04/2004 02:05:32.09 44.90 -74.89 0.18 2.9
NY, 3.2KM S OF MASSENA
* indicates Mc rather than Mn.

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TABLE 4

EARTHQUAKE PHASE DATA LIST FOR EVENTS IN
NEW ENGLAND AND ADJACENT REGIONS

SOUTHEAST MAINE CRUSTAL MODEL
NH, 9KM (5.6MI) SSW OF CONCORD
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  40828 1238 37.92 43- 9.41  71-36.75   5.00   .0 2.4     170   .39  3.0  4.5 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  FFD  35.0 355  EP 9 1238 43.99   6.07   5.81  -.34  .91
                 ES 2 1238 48.19   4.20  10.33  -.34 ****
  HRV  72.4 176  EP 0 1238 49.86  11.95  11.75   .17 1.68                84  2.3
                 ES 3 1238 57.64  19.72  20.91 -1.24  .12
  HNH  81.8 318  EP 3 1238 50.59  12.68  13.23  -.58  .39
  WES  89.0 165  EP 1 1238 52.63  14.71  14.38   .32 1.19              105  2.5
                 ES 0 1238 63.26  25.34  25.60  -.27 1.62
 QUA2 114.9 212  IPD4 1238 58.94  21.02  18.48  2.51  .00                99  2.5
                 ES 1 1238 71.13  33.21  32.90   .26 1.14
  BRY 137.8 177  EP 1 1239   .48  22.56  22.12   .38 1.05
                 ES 1 1239 16.68  38.76  39.38  -.72  .97
  NCB 229.4 293  EPD0 1239 12.49  34.57  34.09   .39 1.09
                 ES 1 1239 38.46  60.54  60.67  -.31  .84
SE OF NEW YORK, HUGHES & LUETGERT
NY, 3.2KM (2MI) S OF MASSENA
 DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
 40904 2 5 32.09  44-53.90  74-53.42    .18   .0      .0 141   .21   .7  2.4 B
 STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
MSNY  11.3  11 EP 1  2 5 33.89   1.80   1.83  -.03 1.40
                S 0  2 5 35.36   3.27   3.25   .01 1.87
 WBO  32.4 290 EP 4  2 5 40.80   8.71   5.04  3.66  .00
                S 4  2 5 44.70  12.61   8.98  3.62  .00
 PTN  36.9 191 EP 2  2 5 37.91   5.82   5.73   .06  .89
                S 3  2 5 42.33  10.24  10.21  -.02  .45
 LOZ  39.4 142 EP 2  2 5 38.10   6.01   6.11  -.16  .88
                S 1  2 5 43.04  10.95  10.87  -.04 1.33
 BGR  41.5 101 EP 1  2 5 38.50   6.41   6.43  -.07 1.33
                S 1  2 5 43.30  11.21  11.45  -.32 1.28
 GAC 100.7 333 EP 1  2 5 47.66  15.57  15.46   .10 1.17
                S 2  2 5 59.41  27.32  27.52  -.21  .77
 NCB 115.9 153 EP 2  2 5 49.87  17.78  17.79  -.11  .75
                S 1  2 5 63.90  31.81  31.67  -.04 1.13
 MNT 120.1  56 EP 1  2 5 50.94  18.85  18.43   .40 1.07
                S 1  2 5 65.08  32.99  32.81   .15 1.12
 MIV 141.7 130 EP 2  2 5 53.65  21.56  21.73  -.22  .70
                S 0  2 5 71.11  39.02  38.69   .25 1.40
ACCN 194.7 150 EP 2  2 6  1.70  29.61  29.81  -.26  .60
                S 1  2 6 25.21  53.12  53.07  -.05  .93
CRLO 232.2 303 EP 4  2 6  5.01  32.92  35.32 -2.43  .00
                S 4  2 6 31.73  59.64  62.88 -3.29  .00
 HNH 246.5 123 EP 1  2 6  9.79  37.70  37.10   .57  .69
                S 3  2 6 39.71  67.62  66.04  1.53  .00
BINY 313.4 196 EP 3  2 6 19.07  46.98  45.35  1.56  .00
                S 4  2 6 55.89  83.80  80.72  2.94  .00
QUA2 356.0 145 EP 4  2 6 26.76  54.67  50.61  4.04  .00
                S 4  2 6 70.94  98.85  90.08  8.72  .00
 HRV 377.9 135 EP 4  2 6 27.87  55.78  53.31  2.44  .00
                S 4  2 6 75.59 103.50  94.90  8.55  .00
 WES 401.3 134 EP 2  2 6 27.74  55.65  56.20  -.56  .21
                S 4  2 6 81.00 108.91 100.04  8.85  .00
SE OF NEW YORK, HUGHES & LUETGERT
04AUG04 CANADA, ONTARIO, OFFSHORE 30 KM (18.6 MI) SOUTH OF PORT HOPE
 DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
 40804 2355 27.02 43-42.51  78-14.48   5.00   .0  .0     151   .58  2.6  4.6 D
 STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
BINY 249.4 132 EP 2 2356  4.62  37.60  37.01   .51 1.30
               ES 3 2356 33.95  66.93  65.87   .92  .62
BRCO 262.2 283 EP 1 2356  6.10  39.08  38.59   .44 1.86
               ES 3 2356 33.82  66.80  68.69 -1.98  .18
CRLO 267.6  15 EP 0 2356  6.20  39.18  39.26  -.11 2.46
               ES 3 2356 38.68  71.66  69.88  1.73  .30
 OTT 274.4  47 EP 1 2356  7.54  40.52  40.09   .42 1.78
               ES 1 2356 38.74  71.72  71.36   .34 1.80
 WBO 276.5  59 EP 1 2356  7.05  40.03  40.35  -.33 1.79
               ES 4 2356 37.64  70.62  71.83 -1.23  .00
 PTN 278.0  70 EP 2 2356  8.13  41.11  40.54   .54 1.17
               ES 2 2356 38.56  71.54  72.16  -.68 1.16
MSNY 305.0  62 EP 2 2356 10.17  43.15  43.87  -.73 1.03
               ES 3 2356 43.32  76.30  78.09 -1.81  .23
 GAC 311.6  45 EP 1 2356 11.14  44.12  44.69  -.58 1.54
               ES 4 2356 44.42  77.40  79.55 -2.17  .00
 NCB 324.7  85 IP 2 2356 12.61  45.59  46.30  -.81  .95
                S 4 2356 55.06  88.04  82.41  5.45  .00
 EEO 332.4 349 EP 3 2356 16.25  49.23  47.25  1.90  .17
               ES 4 2356 54.07  87.05  84.11  2.81  .00
 BGR 332.8  68 EP 4 2356 10.68  43.66  47.30 -3.69  .00
               ES 0 2356 51.31  84.29  84.19   .01 1.89
 GRQ 372.5  30 EP 0 2356 19.17  52.15  52.20  -.11 1.55
               ES 3 2356 61.12  94.10  92.92  1.09  .35
 TRQ 403.1  46 EP 1 2356 23.27  56.25  55.98   .26  .96
               ES 0 2356 66.85  99.83  99.65   .18 1.28
 MNT 417.4  61 EP 1 2356 24.17  57.15  57.75  -.62  .85
               ES 4 2356 67.82 100.80 102.79 -2.03  .00
 VT1 445.6  81 EP 4 2356 36.01  68.99  61.23  7.74  .00
                S 4 2356 86.11 119.09 108.98 10.07  .00
VLDQ 493.3   7 EP 3 2356 35.12  68.10  67.12   .96  .11
               ES 3 2356 85.15 118.13 119.47 -1.38  .10
 MOQ 508.5  69 EP 1 2356 35.85  68.83  68.99  -.30  .27
               ES 1 2356 89.77 122.75 122.80  -.30  .27
 HRV 560.2 104 EP 4 2356 49.83  82.81  75.38  7.40  .00
 BRY 583.3 110 EP 4 2356 56.23  89.21  78.23 10.92  .00
                S 4 2356 61.51  94.49 139.25-44.87  .00
 QCQ 644.8  58 EP 4 2356 49.50  82.48  85.82 -3.36  .00
 DAQ 721.0  49 EP 3 2357  1.38  94.36  95.23 -1.03  .00
               ES 4 2357 74.23 167.21 169.51 -2.59  .00
 LMQ 750.7  55 EP 3 2357  4.82  97.80  98.89 -1.17  .00
               ES 3 2357 82.12 175.10 176.03 -1.06  .00
 CNQ 998.0  51 EP 4 2357 33.61 126.59 129.42 -2.86  .00
 GSQ1034.5  56 EP 4 2357 37.41 130.39 133.94 -3.56  .00
 MNQ1045.1  43 EP 4 2357 40.32 133.30 135.24 -2.03  .00
 ICQ1060.3  52 EP 4 2357 41.92 134.90 137.12 -2.23  .00
 LMN1089.4  77 EP 3 2357 46.77 139.75 140.72 -1.03  .00
 SMQ1137.8  50 EP 3 2357 51.89 144.87 146.69 -1.88  .00
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TABLE 5

MICROEARTHQUAKES AND OTHER NON-LOCATABLE EVENTS

Date

Yr/Mo/Dy
Sta Arrival Time

Hr:Mn:Sec
None recorded this period.


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<

NESN Station Map

Figure 1: Map of stations of the New England Seismic Network (NESN) in operation during the period of this report. Also included are other Northeast U.S. and Canadian seismic stations in operation during this period.

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NESN Strong-Motion Station Map

Figure 2: Map of strong-motion stations of the New England Seismic Network (NESN) in operation during the period of this report.

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NESN Quarterly Seismicity Map

Figure 3: Earthquake epicenters located by the NESN during the period of this report.

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NESN Cumulative Seismicity Map

Figure 4: Seismicity for period October, 1975 - June, 2004.

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Acknowledgments

Our map database has been developedin-house using ArcView and in part basemap data provided byESRI, Inc. (Arcdata Online), USGS GTOPO30 Elevation Data, and TIGER/Line '94, '95, and '97 (US Census Bureau) spatial data.

References

Chaplin, M.P., Taylor, S.R., and Toksöz, M.N. (1980), A coda lengthmagnitude scale for New England, Earthquake Notes, 51, 15-22.

Ebel, J.E. (1982), ML measurements for northeastern UnitedStates earthquakes, Bull. Seism. Soc. Am., 72, 1367-1378.

Rosario, M. (1979), A coda duration magnitude scale for the New EnglandSeismic Network, Master's Thesis, Boston College, 82 pp.

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