The primary objective is to gather data about eastern US seismicity in order to understand the causes of earthquakes, the identification of areas of high seismicity, and the resulting effects. This is a difficult problem: while eastern seismicity is significantly less than that of the western US, potentially damaging earthquakes have occurred, and it is important that we accurately assess the hazard. Lamont operates a seismic network of 30 stations in the middle Atlantic States, ranging from the NY/Canadian Border to south of Baltimore Md. The network is a cooperative operation, with the principal participants SUNY/Potsdam and the Delaware Geological Survey, in addition to Lamont. From October, 1999 through September 2000, over 50 regional earthquakes were recorded. This data, along with data gathered in earlier years, helps us to determine areas of seismicity, as well as ground motion and associated potential damage.

The operation of the Lamont-Doherty Cooperative Seismographic Network (LCSN) to monitor earthquakes in New York, New Jersey, Connecticut, Vermont, Pennsylvania and Delaware is supported under this award. The goal of the project is to compile a complete earthquake catalog for this region to assess the earthquake hazards, and to study the causes of the earthquakes in the region. During October 1999 through September 2000, scientists and engineers at the Lamont-Doherty Earth Observatory of Columbia University (LDEO) satisfactorily carried out three main objectives of the project: 1) continued seismic monitoring for improved delineation and evaluation of hazards associated with earthquakes in the Northeastern United States, 2) improved real-time data exchange between regional networks and the USNSN for development of an Advanced National Seismic System (ANSS) and expanded earthquake reporting capabilities, and 3) to promote effective dissemination of earthquake data and information.

In operating the Lamont-Doherty Cooperative Seismographic Network (LCSN) during Oct. 1999ó Sept. 2000, we accomplished the following:
1) Completed installation of the Earthworm data acquisition and processing system at four subnetworks (24 short-period stations) and at two new sites with broadband seismographs. These Earthworm systems are operating since October 1999 and acquire data in real time.
2) Installation of four new broadband, 3-component seismographs. Each one of these station is operating on the Earthworm system and sending data to the central site at LDEO via Internet.
3) A new USNSN station at NCB (Newcomb, NY in Adirondack Mts.) was installed in coordination with USNSN staff at USGS/Golden in October 1999.
Hence, during the project period, 24 short-period, 4 broadband, and 6 strong ground motion instruments were operated (Figure 1). The primary emphasis was on automatic, prompt data processing and distribution. A significant amount of associated research effort was related to studies of Lg waves and to the issue of induced seismicity. Substantial efforts were made to achieve an efficient real-time earthquake information acquisition and distribution via Internet. LCSN web site has been upgraded to include a real-time, virtual seismogram display on web page, as well as dissemination of waveform data in SEED format via "ftp" from the web site.

About 50 local and regional earthquakes that have occurred in the northeastern United States and southern Canada were detected and located by the LCSN during October 1, 1999 through September 30, 2000. These earthquakes range from magnitude mb(Lg)1.5 to 4.7 (Table 1). A general seismicity pattern during this period is similar to the previous years, showing a relatively higher level of seismicity in the Adirondacks and in the Western Quebéc seismic zone in southern Canada. Other regions with considerable seismicity are: Lancaster ó Reading, PA; western New York around Buffalo; New England and the Charlevoix seismic zone in Canada (see Figure 2).

The Adirondacks: a small earthquake of ML =2.3 occurred on 04/16/2000 at 18:59 just underneath the USNSN station NCB (Newcomb, NY; * =1.8 km from NCB). This event is followed by a much bigger event on 04/20/2000 at 08:46 (ML=3.8, * =3.3 km from NCB). There were 6 aftershocks whose size ranged from ML = -0.17 to 0.8 following the ML=3.8 mainshock. These earthquakes have occurred very close to the mb(P)=5.1 earthquake which have occurred on Oct. 7, 1983 at 10:18 (Goodnow, NY). Another small earthquake occurred near Massena, NY on 02/10/2000. Although the event is small (ML=1.7), seismic signals were well recorded at nearby broadband stations installed in the fall of 1999.

Lancaster ó Reading, PA: three earthquakes of magnitude 1.8 to 2.3 occurred through out the project period. These events follow the main earthquake that occurred in 16 January 1994 (mb(Lg)=4.6) which caused some moderate level of damage ($1.5 million). A key question which must be resolved in the future is:  Are these events induced earthquakes, related to old local mining operation?

Western New York: four small earthquakes of magnitude 1.7 to 2.7 occurred through out the project period around Attica Seismic Zone and around Cuylerville, NY (near to the 12 March 1994 (mb(Lg)=3.6) induced earthquake). Note that these events were located by CNSN (Canadian National Seismographic Network) due to poor coverage of LCSN in western New York.   It is necessary to improve the seismic station coverage in this area.

Southern New York: On Aug. 22, 2000, a small earthquake occurred in Putnam County, about 28 km NE of Peekskill, NY. The event was felt around the epicentral area and was well recorded by Palisades subnetwork stations and a broadband station at PAL (Palisades, NY; * =52 km). This close spacing in stations with on scale digital recordings allows us to study details about the earthquake source and excitation and propagation of ground motion in the eastern US.

Table 1. Selected events for period Oct. 1, 1999 through Sept. 30, 2000

2000/08/22 05:45:14.0     41.420 73.630     07     Mc 2.6     28 km NE of Peekskill, NY

                           2. Adirondacks, New York

2000/01/02 06:46:03.0     44.760 73.700     18     Mn 2.3     20 km W Plattsburgh, NY
2000/01/17 13:30:47.0     44.770 73.690     18     Mn 2.3     20 km NW Plattsburgh, NY
2000/02/10 15:33:26.0     44.980 74.760     06     Mc 1.7     12 km NE Massena, NY
2000/02/27 12:50:32.0     44.610 73.520     18     Mn 1.7     11 km SW Plattsburgh, NY
2000/04/15 08:39:24.0     44.290 75.480     05     Mn 1.5     42 km SW Canton, NY
2000/04/16 18:59:13.0     43.960 74.240     06     ML 2.3      2 km Newcomb, NY, Foreshock
2000/04/20 08:46:55.5     43.949 74.257     05     ML 3.8      3 km Newcomb, NY, Mainshock
2000/04/20 13:13:38.8     43.949 74.257     05     ML 0.8      3 km Newcomb, NY,Aftershock
2000/07/01 07:31:25.0     43.530 75.280     18     Mn 2.3     48 km N of Utica, NY
2000/07/22 05:02:30.0     43.470 75.250     01     Mn 2.7     41 km N of Utica, NY

1999/10/10 04:51:12.0     42.840 77.970     18     Mn 2.3     13 km W Geneseo, NY
1999/11/01 10:12:28.0     42.780 78.930     18     Mn 2.7     12 km S of Buffalo, NY
1999/12/31 11:34:24.0     43.250 78.660     18     Mn 1.7     36 km NE Niagara Falls, NY
2000/01/23 21:46:13.0     43.210 78.870     18     Mn 2.2     15 km W Lockport, NY

1999/10/22 14:37:33.3     40.380 75.927     10     Mc 1.9     5 km N Reading, PA
2000/02/24 14:47:19.0     41.120 75.750     06     Mc 2.3     17 km SE Wilkes-Barre, PA
2000/03/22 20:48:00.0     40.070 76.300     01     Mc 1.8     3 km N Lancaster, PA

1999/10/13 10:09:00.0     42.550 71.440     02     Mc 2.3     14 km SW Lowell, MA
1999/12/25 00:21:41.0     44.940 69.370     05     Mn 3.0     34 km NE Skowhegan, ME
2000/01/03 21:05:49.6     44.335 70.234     05     mb 3.4     26 km N Lewiston, ME
2000/01/17 08:16:19.5     44.632 70.473     05     mb 3.4     11 km NE Rumford, ME
2000/01/21 05:59:50.7     43.007 71.237     05     mb 2.4     16 km NE Derry, NH
2000/01/27 14:49:39.1     42.998 71.163     05     Mn 2.9     19 km NE Derry, NH
2000/06/16 04:02:53.0     42.100 72.800     05     ML 2.8     4 km SW of Westfield, MA
2000/09/07 10:07:40.7     44.353 69.383     05     Md 3.2     28 km SE of Winslow, ME

1999/10/31 20:14:10.0     45.850 74.320     18     mb 3.7     22 km N Lachutte, QUE
2000/01/01 11:22:55.9     46.819 78.883     10     ML 4.7     18 km NE Temiskaming, QUE
2000/02/12 08:31:28.0     45.190 73.780     18     Mn 2.3     27 km S Pointe-Claire, Que
2000/03/02 20:48:29.0     46.120 75.700     18     Mn 3.0     25 km S Maniwaki, Que
2000/05/24 05:41:52.0     45.480 75.400     18     Mn 2.2     10 km S Buckingham, Que
2000/07/11 20:13:55.0     45.340 75.300     18     Mn 2.5     32 km E Ottawa, ONT
2000/08/06 08:52:24.0     46.190 74.970     18     mb 4.0     47 km SE Mont-Laurier, Que

1) Continuous waveform data from broadband, three-component stations

Continuous, 40 samples/sec waveform data from broadband, three-component seismometer (STS-2, T0=120 sec) recorded at PAL (Palisades, NY) are archived at IRIS/DMC in Seattle, WA for further dissemination to other scientists and to public users. Waveform data in SEED format have been submitted.  Current PAL data holdings at IRIS/DMC covers most of 1994 and all of 1999. Interested users can request the waveform data from IRIS/DMC by using e-mail requests and other means. In case of e-mail request, station code is PAL and the network code is "LD". An example data request format is:

PAL LD 1994 08 01 12 00 00.0 1994 01 12 01 00 00.0 3 BHZ BHN BHE

We will continue to submit the continuous, broadband waveform data recorded at PAL and three new sites (LOZ, ACCN, BRNJ) to IRIS/DMC.

2) Waveform data from selected significant earthquakes in northeastern United States

When felt earthquakes or significant events occurs in the northeastern United States, we put seismic phase arrival picks, short-period and broadband waveform data into the LCSN web site which can be easily downloaded by users via the Internet using only a single click. Other event data requested by users, which include neighbouring seismographic network operators; Geological Survey of Canada, Ottawa; high school teachers; and students, are also processed and written into SEED format for download by users. Our experience indicates that this is the most efficient method to disseminate to multiple users without additional effort. The URL for LCSN web site is http://www.ldeo.columbia.edu/LCSN or users can navigate from the LDEO home page at http://www.ldeo.columbia.edu, then click "Solid Earth", followed by "Lamont-Doherty Cooperative Seismographic Network". Waveform data from the selected events in SEED format can be found in "Data Access & Archive" or from the webseismogram window.

Contact person for additional inquiries and assistance:

Name: Jeremiah H. Armitage
Phone: 845-365-8196
E-mail: jha@ldeo.columbia.edu
Data format: SEED, AH, ASCII

Shi, Jinghua, Paul G. Richards and W. Y. Kim, Determination of seismic energy from Lgwaves, BulletinoftheSeismologicalSociety of America, 90, 483-493, 2000.