News and Announcements [in Japanese]
★ Back Numbers ★
1997:No. 41 [Jan], No. 42 [Mar], No. 43 [May], No. 44 [Jul], No. 45 [Sep], No. 46 [Nov]
1998:No. 47 [Jan], No. 48 [Mar]
★地磁気センターニュース No.49／1998年5月1日発行★
１．新着地磁気データ
前回ニュース（1998年3月31日発行,No.48）以降入手、または、当センターで入力したデータ
の内、主なものは以下のとおりです。（観測所名の省略記号等については、データカタログまた
はデータベース'ＧＥＯＭＡＧ'をご参照ください。）
Newly Arrived Data
（１）Analogue Data
Normal Run Magnetograms:
Irkutsuk(Apr-Dec 1996, Apr-Jun 1997), Ekaterinburg(1996), Magadan(1995-96)
Yakutsk(1994)
Annual Reports and etc.:
Finnish Obs.(SOD,NUR,HAN,OUJ, Mar 1998)
Loparskaya(Sep 1997),Lovozero(Jul-Sep 1997)
Kiruna(Jan-Jun 1997), Hatizyo(1996), Dourbes(1997)
（２）Digital Data
Geomagnetic Hourly Values:
Kakioka,Kanoya,Memambetsu(Mar 1998), CBI(Jul-Nov 1997), THJ(1996)
VOS(1993-Jan 1996), Guangzhou(1981-93)
Guimar(1993-95):元Las Mesasが少し移動
ALE(1978,87-91), BOX(1991,93), CSY(1989-96), DNB(1990-92), DVS(1988-96)
FSP(1992), KOM(Jan-Apr 1995), MEA(1976-77, 1990-91), HYB(Jan-Jun 1997)
RES(1971-72,1976-78,1990-91), SUD(Jan-Sep 1995), AQU(1982-94), ARC(1978-91)
BEL(1991-93), BFE(1996-97), COI(1995,Jan-Jun 1996), FUQ(1995, Jan-Mar 1996)
FUR(Jul-Dec 1996), GDH(1996-97), HLP(1966-89), HRB(1995-96), HRN(1978-93)
KRC(1997), KSH(1996), MIR(1995), MZL(1996), NAQ(1996-97),THL(1996-97)
VAL(Jan-Jun 1996)
Geomagnetic 1 Minute Values:
Kakioka,Memambetsu,Kanoya(Mar 1998), CBI(Jul-Dec 1997), Hatizyo(Mar 1998)
BFE(Jul-Dec 1996, Jan-Dec 1997), CSY(1984-95), DIK(1995), DOU(1995)
DVS(1984-96), GDH(1997), HER(Jul 1995-Jun 1996), HLP(Jul-Dec 1996)
HRN(Jul-Dec 1996), MAW(1992-93), MIR(1995), NAQ(1997), THL(1997)
VAL(Mar 1998), VOS(Jan 1992, Feb-Dec 1995), FSP(Jan-Jun, Aug-Dec 1992)
SUD(Jan-Sep 1995)
Geomagnetic 1 Second Values:
KAK,KNY,MMB(Mar 1998), KNY(Jun 1996-Jul 1997), MMB(Apr-Jul 1997)
（３）Kp Index
Kp-Index Table(Mar 1998)
なおデータの注文等は、当センター宛、書面またはＦＡＸにてお願いします。
２．一時間値Ｄｓｔ指数の算出と配布
１９９８年２月までのＤｓｔ指数(Provisional)を算出し、関係機関に配布しました。
ご希望の方は、郵便またはファクシミリにて、京都大学理学部地磁気世界資料解析センターまで
お申し込み下さい。なお、Quick Look Dst(http://swdcdb.kugi.kyoto-u.ac.jp/dstdir/)および
Quick Look AE指数(http://swdcdb.kugi.kyoto-u.ac.jp/aedir/ae/quick.html)は２〜３日の遅
れで当センターのホームページから利用できます。
３．ペルーにおける地磁気観測の歴史と現状（ペルー地球物理研究所・石塚睦）
GEOMAGNETIC OBSERVATIONS IN PERU AND THEIR PRESENT STATUS
INTRODUCTION
The South American region is geomagnetically peculiar. On its west coast at Peru, (13S
lat.) the magnetic equator crosses the south American continent south of the geographic equator
but with a variable distance ranging form about 1300 km in the west side and about 350 km on
the east coast, crossing Peruvian and Brazilian territories from West to East, swerves northward
making an angle of more than 20 degrees until it cuts the geographic equator of the northeastern
coast of Brazil in the Atlantic ocean and later on, once again, both the equators remain parallel in
Africa. In Peru not only is the magnetic equator found far away and nearly parallel to the
geographic equator but this angle and the position of magnetic equator shows continuous secular
changes. Casaverde and Giesecke(1988) described these changes analyzing the progressive and
southward displacement of the magnetic equator since 1712, discussing some of their
characteristics in the South American region.
THE IGY 1957-1959 ACTIVITIES
From July 1957, through 1958 and 1959, the International Geophysical Year (IGY), took
place. Special interest was developed in the equatorial zone and hence Huancayo took a very
active part. The study of the equatorial electrojet was one of the principal activities in Peru, as
cooperative project with the Department of Terrestrial Magnetism of the Carnegie Institution of
Washington. Askania magnetic variographs began with temporary occupation of fourteen stations
between Quito, Ecuador (0.1S lat.) and Maria Elena, Chile (22S lat.). As a result of this
survey five semi permanent stations, i.e., Talara(4.6S lat.,81.3W long.), Chiclayo(6.8S lat.,79.8W
long.), Chimbote(9.1S lat.,78.6W long.), Yauca(15.5S lat.,74.6W long.), and Arequipa(16.5S
lat.,71.5W long.) were installed along the coast of Peru.
Some of these stations had been operating for IGY (1957-1958) campaign but their
activities had been discontinued. On the other hand Arequipa Observatory installed for IGY
purposes is still in operation at present. Additional data were also available from Fuquene,
Colombia, Vassouras, Brazil and Pilar, Argentina. The analysis of these data provided important
knowledge of the electrojet's morphology (Casaverde, 1961)
THE SOLAR ECLIPSES AND EEJ STUDIES IN PERU
The solar eclipse of November 12, 1966 was a very important event in South America.
Very intensive observations of their effects on the EEJ were made in Peru, most of the
measurements were recorded with Askania portable variographs in Peru and Bolivia, (Casaverde
et al., 1967). Another special event was the total eclipse of November 3, 1994. Four temporary
magnetic stations were installed along the central eclipse path.
THE IEEY PROGRAM 1992-1994
Following the recommendations of the IAGA Exeter 1991 General assembly the IGP have
participated carrying an observational program which includes the deployment of 3 component
magnetovariographs latitudinal distributed along the coast of Peru. Some of the IGY 1957-1958
magnetic station were reoccupied (Yauca). The location of the IEEY stations are given in Figure
l. All these stations were in operation simultaneously, since September 1992 to December 1993.
Askania variographs were used initially. Some of the temporary stations were stopped (Casma,
Yauca) while others were upgrade with modern automatic fluxgate magnetometers. (Canete,
Ica).
ANCON GEOMAGNETIC OBSERVATORY
Located at 40 km. north from Lima and 210 km. from Huancayo in a straight line distance,
the Ancon observatory was installed in 1957 by the NASA for satellite tracking purposes. In 1966
the geomagnetic station was installed as part of the geomagnetic network deployed along the total
solar eclipse path occurred on November 12, 1966, for measurements of the geomagnetic effect
(Casaverde et al. 1967), but their activities were discontinued after that observational program.
During 1989 the project for the establishment of an new magnetic Observatory at Ancon
was started with the installation of an H,D and Z Askania Variograph recording on photographic
paper. Dr. T. Kitamura from the Kyushu University installed an high sensitivity Flux-Gate
magnetometer with 3 sec sampling rate. During 1991 an absolute observation house was built up
and a three component ring core fluxgate magnetometer made at the Geophysics Research
Laboratory of the University of Tokyo was installed for continuous operation as main variation
recording system.
HUANCAYO OBSERVATORY
As is well known Huancayo Observatory was established in 1922 by the Carnegie
Institution of Washington. Soon the abnorma11y amplitude of the geomagnetic field diurnal
variation observed led to intensive studies to explain this phenomenon, and finally it was called
"Equatorial Electrojet" by Chapman (1951) and others.
Huancayo has had very important role because of its unique position near the magnetic
equator as well as the long and excellent data supplied by this observatory since the days of
Carnegie. Unfortunately its long standing of data collection was interrupted in December 1992,
when absolute observations were stopped although daily records were continued only as relative
variation.
The first fluxgate magnetometer developed at the University of Tokyo was installed at
Huancayo Observatory in 1984 by Dr. T. Araki. A data logger with 1 sec sampling rate was used
with recording on commercial cassette tape. A second fluxgate magnetometer made at the Kyushu
University was also installed in 1984. The operation of both instruments was stopped in late 1988
and moved to Ancon Observatory due to the terrorist hazard .
As the scientist at IAGA and World wide were quite concerned because Huancayo
Observatory was not reporting magnetic data for more than three years, the IGP Head Committee
decided to resume the normal geomagnetic observations at Huancayo. Reorientation and
recalibrations of the Eschenhagen variometers were made and restarting to operate in middle
1996. Followings are the present status:
a) absolute observations were resumed in July 1996 using new magnetometers donated by the
Japanese government.
b) A three component Ring core fluxgate magnetometer developed at the University of Tokyo
in 1987 was reinstalled in September 1996. The sampling rate used is 10 seconds.
c) A new magnetometer system composed of a proton magnetometer and a three component
fluxgate magnetometer was installed during July 1997 by Dr. M. Kono. This system is part
of a project called "Ocean Hemisphere bottom magnetometer". One second X, Y, Z data
and one minute F data are recorded on a ZIP disk which are changed once a month and
sent to Japan.
REFERENCES
Casaverde, M., and Giesecke A,. Variacion del Ecuador Magnetico en America del Sur., Rev.
Geofisica., IPGH.,No 29, 1988
Casaverde, M., Introduction to Geomagnetism; The Equatorial Electrojet., American Journal of
Physics, Vol 29,No. 11, 1961
Casaverde, M., Giesecke A., R. Salgueiro., and S. Del Pozo., The Equatorial Electrojet and the
Solar Eclipse of November 12,1966., CIW Year book 1967
Chapman, S., The equatoria1 electrojet as detected from the abnormal electric current distribution
about Huancayo, Peru and elsewhere, Arch. Meteorol. Geophys. Bioklimatal, Ser.A, 4, 368, 1951.
MUTUMI ISHITSUKA
INSTITUTO GEOFISICO DEL PERU
OBSERVATORIO DE ANCON
PERU
Fig.1 IEEY stations in Peru
contact on this page: iyemori@kugi.kyoto-u.ac.jp