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A STUDY OF NEW ENGLAND SEISMICITY

Quarterly Earthquake Report

April - June, 2002


New England
Seismic Network

Weston Observatory
381 Concord Road
Weston, MA 02493
Earth Resources Lab
Massachusetts Institute of Technology
42 Carleton Street
Cambridge, MA 02142



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 # 1434-HQ-98-AG-01943
M. Nafi Toksöz, Principal Investigator
Earth Resources Lab
Dept. of Earth, Atmospheric, and Planetary Sciences
Massachusetts Institute of Technology
42 Carleton Street
Cambridge, MA 02142
Email: toksoz@mit.edu
Award # 1434-HQ-98-AG-01926

Prepared by Anastasia Macherides Moulis
Email: weston.observatory@bc.edu
January, 2003

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 1434-HQ-98-AG-01943 and award number 1434-HQ-98-AG-01926. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.

Quarterly Earthquake Report
April - June, 2002

Table of Contents

Introduction

The New England Seismic Network (NESN) is operated collaboratively by the Weston Observatory (WES) of Boston College and the Earth Resources Lab (ERL) of the Massachusetts Institute of Technology. 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 of the 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 April - June, 2002. 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 9 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 currently consists of 14 broadband three-component, 4 short-period vertical, and 8 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.

WES now operates 13 stations with broadband instruments consisting of Guralp CMG-40T three-component sensors. Ground motions recorded by these sensors aredigitized 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 andarchiving. During the year 2001, two new seismic stations were added to the WES network. Station UMM was placed in northeastern Maine and station FFD was placed in central New Hamps hire. Station MIM, in central Mainewas dismantled. WES also maintains 8 SMA-1 strong-motion instruments in New England.

ERL at MIT currently operates 4 short-period stations, all located within 100 km of Boston. The short- period instruments have 1.0 Hz L4C vertical seismometers. Data recorded by these seismometers is transmitted continuously in analog mode to ERL and digitized (12-bit) into a PC at 50 sps. A data acquisition program on the PCtriggers on events detected in the short-period data streams and saves them toa disk for manual analysis. Station WFM also has a new three-component, highdynamic range instrument . The instrument has a CMG-40T sensor and transmits 3-channel, 24-bit data at 100 sps continuously to a central processor (Pentium PC) at ERL. Waveform windows of suspected events are extracted from the data stream, analyzed and archivedwith the short-period data. WES and ERL record some stations in analog format on helicorders to provide additional data for analysis.

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Seismicity

There were 9 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 via FTP at: SEISMOEAGLE.BC.EDU. Waveform data are saved in Nanometrics, ASCII, and SEED formats and are available via SEISMOEAGLE.BC.EDU or through personal contact. Earthquake lists can be fingered at QUAKE@SEISMOEAGLE.BC.EDU. Weston Observatory maintains two web pages with information about local earthquakes: "http://www.bc.edu:80/bc_org/avp/cas/wesobs/" and "http://seismoeagle.bc.edu/". The latter page is still under contruction. Currently available on the seismoeagle web page is the full catalog of northeastern U.S. earthquake activity to 1992. This will be updated as new Northeastern U.S. Seismic Network Bulletins are produced.

MIT/ERL provides two internet utilities, the MIT/ERL web-site("www-erl.mit.edu/NESN/homepage.html") and an anonymousFTP directory, to distribute seismic data. SESAME (Seismic Event Server atMIT/ERL) is the web data server that distributescatalogs, rep orts, earthquake bulletins, and epicenter and station maps(including an archive of recent seismic events). The FTP site,named "sunda.mit.edu", is the current facility available to download waveformdata recorded by the MIT NESN. The client machineIP numbe r must be forwarded to us for the client to gain access to theanonymous FTP directory. After logging on, the user changesdirectories to "pub/seismic". Waveforms of individual events for the period April 1995 through the present are accessed as Unix-compr essed SAC files, through the anonymous FTP directory. A "readme"file offers further explanation about the data. Older waveform data in SAC format (1981 - March 1995) will be made available on the FTP site upon request.

For more information on matt ers discussed in this report or general earthquake information (reports, maps, catalogs, etc.) consult our web-sites www-erl.mit.edu/NESN and www.bc.edu:80/bc_org/avp/cas/wesobs/ or contact:

Robert Cicerone
MIT Earth Resources Lab
42 Carleton Street
Cambridge, MA 02142

Voice: 617-253-7863 / FAX: 617-253-6385 / Email: cicerone@erl.mit.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 = station 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. Date = 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 separation, 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 arrival
    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 arrival
  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 = signal 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 = nearest 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 weston.observatory@bc.edu
Edward Johnson Project Engineer 617-552-8332 johnson@bc.edu
Patricia Tassia Administrative Secretary 617-552-8311 tassia@bc.edu
W. Richard Ott, S.J. Assistant to the Director 617-552-8335 ottwi@mail1.bc.edu
Weston Observatory
617-552-8300
617-552-8388 (FAX)



     

MIT/ERL PERSONNEL

Name

Network Position voice phone email address
M. Nafi Toksöz Principal Investigator 617-253-7852 toksoz@mit.edu
Robert Cicerone Research Seismologist 617-253-7863 cicerone@erl.mit.edu
Heather Hooper Seismic Analyst 617-253-6290
Sara Brydges Administrator 617-253-7797 sara@erl.mit.edu
Earth Resources Lab
617-253-8027
617-253-6385 (FAX)



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TABLE 2



     

SEISMIC STATIONS OF THE NEW ENGLAND SEISMIC NETWORK

Code Lat Long Elev (m) Location Operator
BCX 42.3350 -71.1705 61.0 Chestnut Hill, MA WES
BRY 41.9178 -71.5388 380.0 Smithfield, RI WES
DNH 43.1225 -70.8948 24.0 Durham, NH MIT
DXB 42.0610 -70.6992 8.0 Duxbury, MA MIT
FFD 43.4702 -71.6533 131.0 Franklin Falls Dam, NH WES
GLO 42.6403 -70.7272 15.2 Gloucester, MA MIT
HNH 43.7050 -72.2860 180.0 Hanover, NH WES
NH1 43.5473 -71.5743 402.0 Sanbornton, NH WES
QUA2 42.2789 -72.3525 168.0 Belchertown, MA WES
TRY 42.7311 -73.6669 131.0 Troy, NY WES
UMM 44.7100 -67.4583 35.0 Machias, ME WES
VT1 44.3317 -7 2.7536 410.0 Waterbury, VT WES
WES 42.3850 -71.3220 60.0 Weston, MA WES
WFM 42.6106 -71.4906 87.5 Westford, MA MIT
WVL 44.5648 -69.6575 85.0 Waterville, ME WES
YLE 41.3100 -72.9269 914.0 New Haven, CT WES
PQI 46.6710 -68.0168 175.0 Presque Isle, ME WES

     

STRONG MOTION STATIONS OF THE NEW ENGLAND SEISMIC NETWORK

Code Lat Long Location Operator
SM1 44.90 -67.25 Dennysville, ME WES
SM2 44.49 -73.10 Essex Junction, VT WES
SM3 41.45 -71.33 Newport, RI WES
SM4 42.38 -71.32 Weston, MA WES
SM5 42.66 -71.30 Lowell, MA WES
SM6 42.30 -71.34 Natick, MA WES
SM7 42.39 -71.54 Hudson, MA WES
SM8 44.48 -69.61 North Vassalboro, ME WES

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TABLE 3



     

EARTHQUAKE HYPOCENTER LIST
NEW ENGLAND AND ADJACENT REGIONS
April - June, 2002

Date
Yr/Mo/Dy
Time
Hr:Mn:Sec
Lat Long Depth
(km)
Mag Int Location
2002/04/04 02:48:40.25 43.1275 -71.7092 9.80 1.6
NH, 10.5 KM SE OF HENNIKER
2002/04/20 10:50:47.50 44.5100 -73.7000 11.00 5.1
NY, 28 KM SW OF PLATTSBURGH
2002/04/20 11:04:43.34 44.3252 -73.6197 5.00 4.0
NY, SSW OF PLATTSBURGH (AFTERSHOCK)
2002/05/11 20:51:55.50 44.8987 -69.0822 0.27 2.2
ME, 10 MI NE OF NEWPORT
2002/05/24 23:45:59.36 44.5490 -73.6908 5.00 3.2
NY, 25 KM SW OF PLATTSBURGH
2002/05/28 09:15:39.23 45.5105 -76.5962 5.00 3.6
ONTARIO CANADA, 65 MI WNW OF OTTOWA
2002/06/01 11:35:35.19 45.3043 -74.2483 37.95 3.1
QUEBEC CANADA, 1 5 MI WNW OF MONTREAL
2002/06/07 10:16:04.12 42.1615 -71.5578 7.13 2.5
MA, 4 KM NW OF MILFORD
2002/06/25 13:40:35.18 44.2243 -73.3608 1.23 2.9
NY, 30 KM SSW OF BURLINGTON
* indicates Mc rather than Mn.

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TABLE 4

EARTHQUAKE PHASE DATA LIST
NEW ENGLAND AND ADJACENT REGIONS
April - June, 2002

 SOUTH & COASTAL NEW ENGLAND, CHIBURIS, 1979
02APR04 NH, 10.5 KM SE OF HENNIKER
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20404  248 40.25 43- 7.65  71-42.55   9.84  1.6         152  0.58  6.9  8.3 D
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  FFD  38.3   7 EP 1  248 47.53   7.28   6.58  0.69 1.43
                 S 1  248 51.64  11.39  11.72 -0.33 1.49
  HNH  79.4 324 EP 3  248 54.42  14.17  13.15  0.99 0.40
                 S 0  248 63.57  23.32  23.40 -0.13 1.83
  WES  88.4 159 EP 0  248 54.69  14.44  14.51 -0.09 1.80  14 .06  1.5
                 S 3  248 64.92  24.67  25.83 -1.18 0.36
 QUA2 108.0 209 EP 3  248 58.63  18.38  17.49  0.86 0.40  18 .08  1.7
                 S 3  248 70.05  29.80  31.13 -1.39 0.29
NORTHERN NY AND ADIRONDACKS
02APR20 NY, 28 KM SW OF PLATTSBURGH
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20420 1050 47.50 44-30.60  73-42.00  11.00   .0  .0     232   .24  2.6  1.4 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  BGR  64.1 304 EPC4 1050 99.99  52.49  10.03 42.41  .00
  LOZ  71.1 280 EPC4 1050 99.99  52.49  11.09 41.33  .00
  NCB  73.1 215 EPD0 1050 59.00  11.50  11.38   .02 1.62
  VT1  78.0 105 IPD0 1050 59.48  11.98  12.12  -.16 1.60
                ES 0 1050 68.75  21.25  21.57  -.35 1.58
  PTN 102.3 274 EPC4 1050 99.99  52.49  15.79 36.67  .00
  MNT 110.5   3 EPC4 1051 21.73  34.23  17.03 17.18  .00
 FINE 120.0 257 EPC4 1050 99.99  52.49  18.47 33.96  .00
 CHIP 122.7 285 EPC4 1050 99.99  52.49  18.89 33.58  .00
  WBO 136.0 294 EPD4 1051 41.60  54.10  20.89 33.20  .00
  HNH 144.3 128 IPD0 1051  9.67  22.17  22.15  -.01 1.38
 LBNH 144.5 102 EPD4 1051 99.99 112.49  22.17 90.26  .00
  MOQ 144.9  52 EPD4 1051 22.08  34.58  22.23 12.21  .00
  BRC 150.0 266 EPC4 1050 99.99  52.49  23.02 29.46  .00
  OTT 186.8 302 EPD4 1051 99.99 112.49  28.33 84.15  .00
  GAC 192.8 313 EPD4 1051 39.20  51.70  29.07 22.62  .00
  FFD 200.7 125 EPD0 1050 77.72  30.22  30.05   .15 1.17
  TRQ 201.7 341 EP 4 1051 26.93  39.43  30.17  9.26  .00
 KGNO 224.7 262 EPD4 1051 99.99 112.49  33.01 79.47  .00
  DPQ 251.7  17 EPC4 1051 13.39  25.89  36.34-10.45  .00
 QUA2 270.8 156 EPC0 1050 86.08  38.58  38.70  -.15  .95
  WES 304.7 141 IPC0 1050 90.04  42.54  42.88  -.35  .82
  BCX 316.8 140 EPC1 1051 33.15  45.65  44.38  1.24  .02
 LSCT 317.0 173 EPC4 1051 99.99 112.49  44.39 68.05  .00
 BINY 317.1 216 EPC4 1051 99.99 112.49  44.40 68.01  .00
  WVL 320.8  90 EPD0 1051 32.11  44.61  44.87  -.27  .77
 CRLO 334.9 300 EPD4 1051 99.99 112.49  46.61 65.85  .00
  YLE 361.1 170 EPC4 1051 40.53  53.03  49.84  3.19  .00
 WLVO 381.1 260 EPD4 1051 99.99 112.49  52.31 60.17  .00
  A11 407.6  42 EPC4 1051 39.28  51.78  55.58 -3.81  .00
  A54 414.9  38 EPC4 1051 99.99 112.49  56.48 55.95  .00
  LMQ 427.0  38 EPC4 1051 99.99 112.49  57.98 54.44  .00
 SADO 433.0 274 EPD4 1051 99.99 112.49  58.72 53.73  .00
 PKRO 433.6 262 EPD4 1051 99.99 112.49  58.79 53.67  .00
  A16 435.7  41 EPD4 1051 42.85  55.35  59.05 -3.70  .00
  A61 450.7  38 EPC4 1051 42.36  54.86  60.90 -6.05  .00
 STCO 462.7 252 EPD4 1051 99.99 112.49  62.39 50.08  .00
  A64 471.6  39 EPC4 1051 46.01  58.51  63.48 -4.99  .00
  EEO 481.6 299 EPD4 1051 99.99 112.49  64.71 47.71  .00
 VLDQ 493.9 324 EPD4 1051 99.99 112.49  66.24 46.23  .00
  UMM 496.1  87 EPD1 1051 53.10  65.60  66.51  -.92  .09
 ACTO 519.2 259 EPD4 1051 99.99 112.49  69.37 43.06  .00
 TYNO 520.9 252 EPD4 1051 99.99 112.49  69.57 42.89  .00
 HGVO 545.9 252 EPD4 1051 99.99 112.49  72.66 39.79  .00
 ELGO 547.4 260 EPD4 1051 99.99 112.49  72.84 39.59  .00
  GGN 548.4  83 EPD4 1051 99.99 112.49  72.97 39.51  .00
 BRCO 616.2 267 EPD4 1051 99.99 112.49  81.33 31.11  .00
SOUTH & COASTAL NEW ENGLAND, CHIBURIS, 1979
02APR20 NY, SSW OF PLATTSBURGH (AFTERSHOCK)
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20420 11 4 43.34 44-19.51  73-36.88   5.00  4.0         297  0.58  8.8  5.9 D
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  VT1  68.7  89 IPD2 11 4 54.47  11.13  11.44 -0.33 1.75
                 S 0 11 4 63.64  20.30  20.37 -0.10 3.50
  HNH 126.9 123 EPD3 11 5  4.96  21.62  20.67  0.91 0.71
  FFD 184.0 121 IPU2 11 4 72.96  29.62  28.86  0.76 1.29
  WES 284.6 139 IP 1 11 5 24.63  41.29  41.27  0.01 1.45
                 S 4 11 5 61.98  78.64  73.47  5.15 0.00
  WVL 315.4  86 EP 3 11 5 27.99  44.65  45.08 -0.44 0.42
                 S 3 11 5 65.25  81.91  80.24  1.66 0.21
  BRY 316.4 148 EP 3 11 5 27.44  44.10  45.20 -1.10 0.37
                 S 3 11 5 62.11  78.77  80.46 -1.69 0.21
  UMM 491.5  85 EPD3 11 5 49.18  65.84  66.82 -1.00 0.10
SOUTHEAST MAINE CRUSTAL MODEL
02MAY11 ME, 12 MI NE OF NEWPORT
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20511 2051 55.50 44-53.92  69- 4.93    .27  2.2  .0     129   .48  2.7  5.0 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  WVL  61.8 229 IPD3 2052  2.61   7.11  10.30 -3.20  .01  59 .11  1.8
                ES 4 2052  8.68  13.18  18.34 -5.17  .00
  UMM 130.2  99 IPD1 2052 15.89  20.39  21.15  -.77 1.41  77 .13  2.4
                ES 4 2052 30.62  35.12  37.65 -2.54  .00
  GGN 179.9  82 EP 0 2052 24.25  28.75  28.50   .24 1.68
 LBNH 237.4 252 EP 0 2052 31.25  35.75  35.60   .09 1.42
                ES 0 2052 58.46  62.96  63.37  -.51 1.42
  MOQ 253.9 280 EP 1 2052 33.87  38.37  37.64   .59  .98
  FFD 259.7 232 ES 1 2052 64.01  68.51  68.27   .20  .99 103 .20  2.9
  HNH 288.0 243 EP 4 2052 40.75  45.25  41.85  3.37  .00  12 .18  2.1
                ES 4 2052 72.11  76.61  74.49  2.07  .00
  A16 294.4 346 EP 4 2052 71.37  75.87  42.64 33.23  .00
  A54 302.3 340 ES 0 2052 73.12  77.62  77.65  -.13 1.12
  A61 320.2 346 EP 3 2052 39.38  43.88  45.83 -1.96  .16
                ES 0 2052 77.58  82.08  81.58   .48 1.03
  A64 331.4 349 ES 0 2052 79.80  84.30  84.03   .24  .99
  WES 332.8 213 EP 4 2052 47.48  51.98  47.38  4.59  .00   7 .23  1.9
                ES 4 2052 84.08  88.58  84.34  4.23  .00
  DPQ 348.9 305 ES 0 2052 83.14  87.64  87.88  -.24  .91
  LMN 351.2  72 EP 0 2052 45.73  50.23  49.65   .52  .89
                ES 4 2052 81.75  86.25  88.38 -2.23  .00
NORTHWEST MAINE CRUSTAL STRUCTURE
02MAY24 NY, 25 KM SW OF PLATTSBURGH
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20524 2345 59.36 44-32.94  73-41.45   5.00  3.2  .0     152   .46  2.2  3.3 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  NCB  77.0 213 IPD1 2346 11.54  12.18  12.56  -.48 1.75
                 S 3 2346 20.66  21.29  22.35 -1.24  .40
  PTN 102.6 271 EP 1 2346 16.41  17.04  16.62   .40 1.66
                 S 1 2346 28.96  29.59  29.58  -.04 1.68
 MSNY 105.3 298 EP 2 2346 16.96  17.59  17.04   .55 1.08
                 S 2 2346 29.22  29.85  30.33  -.49 1.10
  HNH 146.5 130 EPC1 2346 23.29  23.93  23.58   .32 1.50 548 .22  3.2
                 S 4 2346 39.44  40.07  41.97 -1.95  .00
  FFD 202.7 126 EPD4 2346 35.02  35.66  31.48  4.15  .00
                 S 0 2346 55.47  56.10  56.04   .03 1.73
  HRV 285.1 143 EP 2 2346 41.46  42.09  41.66   .41  .65
  WES 307.4 141 EPD0 2346 43.41  44.04  44.42  -.38 1.20 169 .26  3.2
                 S 3 2346 79.67  80.30  79.06  1.22  .19
  WVL 320.1  90 IPC0 2346 44.97  45.60  45.98  -.38 1.14 156 .25  3.2
                 S 3 2346 79.32  79.96  81.84 -1.90  .02
 BINY 321.0 215 EPN2 2346 46.22  46.85  46.09   .68  .54
                ES 4 2346 84.84  85.48  82.04  3.29  .00
  PAL 394.2 183 EPN2 2346 55.11  55.75  55.13   .60  .37
NORTHWEST MAINE CRUSTAL STRUCTURE
02MAY28 ONTARIO CANADA, 65 MI WNW OF OTTAWA
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20528  915 39.23 45-30.63  76-35.77   5.00  3.6  .0     280   .47  4.0  3.7 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
 MSNY 147.4 113 EPN3  916  2.43  23.20  23.73  -.54  .63
  PTN 164.5 129 EPN3  916  5.20  25.97  26.43  -.49  .62
                ES 2  916 26.41  47.18  47.05   .07 1.26
  LOZ 186.9 122 EPN2  916  8.07  28.84  29.53  -.76 1.12
                ES 1  916 31.58  52.35  52.56  -.34 1.80
  NCB 254.2 132 EPN1  916 17.09  37.86  37.85  -.09 1.58
                ES 4  916 41.52  62.29  67.37 -5.26  .00
  VT1 330.6 113  S 3  917  5.67  86.44  84.15  2.26  .01 605 .30  3.7
 ACCN 332.0 135 EPN1  916 27.36  48.13  47.45   .62 1.28
                ES 4  916 66.61  87.38  84.47  2.81  .00
 BINY 371.9 172 EPN0  916 31.64  52.41  52.37  -.04 1.55
                ES 0  916 72.80  93.57  93.22   .21 1.55
 LBNH 395.0 111 EPN1  916 35.07  55.84  55.23   .56 1.07
                ES 4  916 75.69  96.46  98.30 -1.95  .00
  HNH 396.7 120 EPD2  916 35.83  56.60  55.44  1.13  .60 132 .45  3.1
                 S 4  916 86.72 107.49  98.68  8.76  .00
  FFD 453.8 120 EPC4  916 50.08  70.85  62.49  8.35  .00 379 .27  3.9
                 S 4  916 97.07 117.84 111.22  6.58  .00
 SSPA 551.7 191 EPN1  916 53.38  74.15  74.57  -.45  .51
  MVL 612.6 178 EP 0  916 61.40  82.17  82.09   .06  .41
NORTHWEST MAINE CRUSTAL STRUCTURE
02JUN01 QUEBEC CANADA, 15 MI WNW OF MONTREAL
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20601 1135 35.19 45-18.26  74-14.90  37.95  3.1  .0     258   .24  4.4 30.3 C
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
 MSNY  59.0 235 EP 0 1135 46.12  10.93  10.81   .11 1.45
  LOZ  80.5 199 EP 0 1135 48.76  13.57  13.46   .03 1.43
  PTN  99.9 216 EP 0 1135 50.90  15.71  15.85  -.18 1.41
  NCB 148.2 179 EP 1 1135 57.56  22.37  21.81   .45  .91
  VT1 160.2 132  S 1 1136 16.39  41.20  41.47  -.31 1.00 522 .19  3.3
 ACCN 218.3 168 EP 3 1136  4.73  29.54  30.47 -1.00  .06
 LBNH 218.5 123 EP 4 1136   .95  25.76  30.50 -4.80  .00
  HNH 236.5 139 EPD0 1136  8.03  32.84  32.72   .09 1.27  39 .17  2.5
                 S 0 1136 33.58  58.39  58.24   .09 1.27
  FFD 290.3 135 EPD1 1136 14.73  39.54  39.36   .16  .91 439 .27  3.5
                 S 4 1136 48.33  73.14  70.06  3.04  .00
  WVL 372.0 103  S 4 1136 65.15  89.96  88.01  1.93  .00
 BINY 373.0 202  P 0 1136 24.65  49.46  49.56  -.19 1.14
  PAL 478.5 177  P 2 1136 36.86  61.67  62.59  -.95  .15
  UMM 539.5  97  S 4 1136 94.54 119.35 124.81 -5.48  .00
SOUTHEAST MAINE CRUSTAL MODEL
02JUN07 MA, 4 KM NW OF MILFORD
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20607 1016  4.12 42- 9.69  71-33.47   7.13  2.5  .0     139   .20   .9  2.5 B
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  BRY  27.1 177 IPC0 1016  8.79   4.67   4.59   .02 1.31
                ES 0 1016 12.31   8.19   8.17  -.09 1.31
  WES  31.5  38 EPD0 1016  9.57   5.45   5.28   .16 1.28 141 .06  1.9
                ES 0 1016 13.38   9.26   9.40  -.16 1.30
 QUA2  66.9 281 IPD0 1016 15.35  11.23  10.89   .32 1.16 332 .10  2.6
                IS 0 1016 23.27  19.15  19.38  -.28 1.20
  FFD 145.6 357 EP 2 1016 27.79  23.67  23.36   .29  .49 500 .12  3.3
                ES 2 1016 44.62  40.50  41.59 -1.12  .03
  HNH 181.5 341 EP 0 1016 32.06  27.94  27.96  -.05  .92  29 .06  2.5
                ES 4 1016 51.72  47.60  49.77 -2.22  .00
 LBNH 232.8 353 EP 4 1016 40.94  36.82  34.30  2.47  .00
  PAL 234.4 237 EP 4 1016 40.19  36.07  34.49  1.56  .00
  NCB 295.8 313 EP 4 1016 50.50  46.38  42.07  4.21  .00
  WVL 304.6  30 ES 4 1016 77.00  72.88  76.82 -3.95  .00  13 .16  2.3
 BINY 365.7 271 EP 4 1016 61.59  57.47  50.70  6.70  .00
  PTN 385.7 314 EP 4 1016 63.71  59.59  53.16  6.40  .00
NORTHERN NY AND ADIRONDACKS
02JUN25 NY, 30 KM SSW OF BURLINGTON
  DATE     ORIGIN    LAT N    LONG W   DEPTH   MN  MC  ML GAP   RMS  ERH  ERZ Q
  20625 1340 35.18 44-13.46  73-21.65   1.23  2.9  .0     277   .15  2.4  2.5 B
  STN  DIST AZM  RMK HRMN   SEC   TOBS   TCAL   RES   WT AMX PRX XMAG FMP FMAG
  VT1  49.9  76 EPD4 1340 40.66   5.48   7.98 -2.52  .00
                 S 3 1340 49.39  14.21  14.21  -.04  .71
  HNH 103.8 124 EPC4 1340 44.36   9.18  16.14 -6.99  .00 213 .16  2.6
                 S 4 1340 57.44  22.26  28.74 -6.53  .00
  FFD 160.9 121 EPC1 1340 59.87  24.69  24.81  -.14 1.63
                 S 4 1340 83.17  47.99  44.16  3.79  .00
 QUA2 231.1 159 EPC1 1341  9.88  34.70  34.71  -.04 1.36 354 .31  3.2
                 S 4 1341 39.49  64.31  61.78  2.48  .00
  WES 262.9 141 EPC4 1341 16.03  40.85  38.64  2.20  .00  78 .22  2.8
                 S 3 1341 44.35  69.17  68.78   .38  .25
  WVL 296.3  83 EPC1 1341 18.14  42.96  42.75   .20 1.04  60 .21  2.8
                 S 4 1341 54.45  79.27  76.10  3.16  .00
  UMM 472.5  83 EPD4 1341 55.38  80.20  64.51 15.68  .00  34 .24  2.9

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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 period April - June, 2002. Also included are the US National Seismic Network stations operating in New England 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 period April - June, 2002.

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NESN Quarterly Seismicity Map

Figure 3: Earthquake epicenters located by the NESN during period April - June, 2002.

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NESN Cumulative Seismicity Map

Figure 4: Seismicity for period October, 1975 - June, 2002.

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Acknowledgments

We would like to thank the Undergraduate Research Opportunities Program (UROP) of MIT for its support to the network. Our map database has been developed in-house using ARCINFO and in part basemap data provided by ESRI, 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 length magnitude scale for New England, Earthquake Notes, 51, 15-22.

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

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