Title: Seismic Data Transmitting and creating Nigerian National Network of

Seismic Stations - Conception and realisation of a GPRS/APN Technology

Dauda Duncan1

Centre for Geodesy and Geodynamics

PMB 011, Toro, Bauchi State

Nigeria

Tel:+2348033539685

Email: daudadawud@yahoo.com.uk

Lame G. U.2

Centre for Geodesy and Geodynamics

PMB 011, Toro, Bauchi State

Nigeria

Email: lame.garba@yahoo.com

ABSTRACT

In order to meet the requirements of remote and central stations data transmission,

a telecommunication system which is moderate in electric power consumption and

price essential in Nigeria should be in place, due to poor and unreliable access to

electricity in remote areas. VSAT, point-to-point radio connections, DSL and so

many more are expensive, demand much more power and not portable.

GPRS/APN technology integrated with required communication systems provides

efficient, handy and cost effective process as well as reduction in trade-off between

bandwidth and coverage. In other words, a special problem about real-time data

transmission of is partially resolved and communication among stations. This

simple and reliable method can be also applied to collection of seismic data from

remote stations to central station and also Virtual Private Network (VPN) can be

created once a static IP address is assigned to each SIM provided by GSM operator

to make the seismic network secured and independent. Seismic network needs to

be online and real –time so that events could be processed and analysed to obtain

earthquake epicenters, coda magnitude, tremors etc on time.

The seismic equipment of Centre for Geodesy and Geodynamics, Toro, Nigeria

who installed their first seismic equipment in 2008.The equipment have being

stand-alone systems hence collection of seismic data were done manually that is

users and operators travel across Nigeria to put together data.

Keys words: seismic data, seismic network, GPRS/APN, GSM, VPN, IP address, earthquake

INTRODUCTION

One seismic station does not make a network and in locating earthquake origins,

magnitudes and their codas at least three seismic stations are needed. As a result

networking of the stations is a primary procedure in seismic programme. Setting

up a network is mainly a question about transmitting and communication and this

field is in rapid development and will probably completely change the concept of

how to design seismic networks.

Earlier, a network was often a tightly linked system like the classical

microearthquake network of analog radio telemetered stations a few hundred

kilometers away sending analog data from the field stations to a central digital

recorder. While these types of networks still are being built using digital

transmission, the trend is for field stations to become independent computer nodes

which, by software, can be linked together in virtual seismic networks, so called to

distinguish them from the more classical physical networks.

So, in the virtual network, the communication system is a design part separated

from the seismic stations themselves. The communication can be based on radio,

satellite or public data communication channels.

Particularly, in Nigeria, seismic stations across Nigeria as shown in fig. 1 and table

1, transmission of seismic data from remote units to a central station unit via a

VSAT, point-to-point radio connections to extend cable telemetry spreads, DSL

Standard dialup technologies would be a difficult one due to bulky nature,

expensive and most importantly the power consumption of the usual technologies.

Access Point Name (APN) provides routing information for GPRS and it consists

of two parts; the Network ID, which identifies the external service requested by a

user of the GPRS service, and the Operator ID, which specifies routing

information.

The utilization of GPRS/APN technology tends to moderate and optimize the

available resources to realize near real-time transmission of data for disks sharing

of various seismic recorders.

MNA

ABJ

KAD

TOR

IFE IBN

OYO

NSU ABK

AW

K

Fig. 1 Seismic stations across Nigeria

S/N Station

Name

Latitude Longitude Elevation (m) Geologic

Foundation

Instrumentation

1 Oyo 07°53.131′N 03°57.078′E 295 Granite No Instrument Installed

2 Ibadan 07°27.251′N 03°53.520′E 193 Gneiss No instrument installed

3 Ile-Ife 07°32.800′N 04°32.815′E 289 Gneiss EP105 broadband seismometer,

DR4000 recorder

4 Awka 06°14.561′N 07°06.693′E 50 Shale and

siltstone

No instrument installed

5 Nsukka 06°52.011′N 07°25.045′E 430 Sandstone EP105 broadband seismometer,

DR4000 recorder

6 Abakiliki 06°23.453′N 08°01.474′E 82 Sandstone No instrument installed

7 Abuja 08°59.126′N 07°23.380′E 432 Granite No instrument installed

8 Toro

(Central)

10°03.303N

09°07.089′E 882 Gneiss No instrument installed

9 Kaduna 10°26.101′N

07°38.484′E 668 Granite EP105 broadband seismometer,

DR4000 recorder

10 Minna 09°30.702′N 06°26.411′E 203 Granite No instrument installed

Table 1 Location of Nigeria Seismological Stations

Method of (Near) real-time seismic data transfer using GPRS/APN

Technology

Disks sharing of various seismic recorders in the network using GPRS/APN setting

as shown in fig. 2 and creating VPN enables transfer of data online real time. With

NetBIOS over TCP/IP protocol integrated in a modem and the seismic recorder,

disk sharing becomes realistic.

At the data centre, the seismic station is equipped with broadband seismometer

and portable multi-channel low power data Acquisition system. The acquisition

system is characterized with stand-alone recording as well as remote data retrieval

modem via telephone line, radio telemetry, and direct connection to a PC-based

workstation via Ethernet or wireless LAN.

Receiving the data would be done in near real time from the selected seismic

stations across Nigeria as well as chosen global seismic network. Using

GPRS/APN connections data would be received across network, as well as other

seismic network.

In GPRS/APN technology, connecting remote seismic recorders which are

equipped with Ethernet to a cellular/GSM network, it must be taken into account

the requirements of the application and the available IP addressing schemes

available by the GSM company. Specifically, consideration must be given in

wireless solutions regarding which side of the connection initiates communication.

Wireless Operators offer private APN's with static IP address support thereby

letting the clients have their own private network within the GPRS network.

Each wireless carrier handles usage and management of IP addresses differently,

therefore clients must be prepared to carefully examine the type of IP connectivity

options available and make sure that they work with the targeted application.

Most importantly, to establish a communication through GPRS supplied by your

Cellular Network Operator, the configuration needed should usually involve

GPRS/EDGE/3G modem router. Currently Multnet Mobile router which has being

used and tested elsewhere. Once the mobile router is compatible the Private

seismic network (can be shared), APN a point-to-point network with static IP

address can be set up by the cellular service provide. The service provider makes

available a specific static IP-address to each cellular sim-card so that when the

particular SIM-card is inserted into the GPRS –modem in the router and connects

to the Private APN. The network must always be assigned with the same IP-

address.

Moreover, to access devices beyond the mobile router, port forwarding needs to be

configured. This will forward incoming packets to the attached device on the

remote network to communicate to that device from a central server, the router’s

PPP IP address should be configured as the address for the remote device. Once

port forwarding has been set up, the router will forward the packets and the remote

readers can be communicated to on the SIM IPs.

Since private APN essentially gives the mobile router an entry point into an IP-

based data network that is static IP on each mobile router, a virtual private network

(VPN) could be created across the several seismic stations, enabling privacy and

tunneling of non-TCP/IP protocols. Furthermore, instead of using more expensive

permanent means like VSAT, radio modems at each site with several repeaters, we

can have 2 categories of VPNs to achieve additional more protected and opened

network namely:

i. Remote access VPN where remote users of the seismic data like

telecommuter securely access the data in the network whenever and

wherever they need to do.

ii. Extranet VPN where external people would be allowed to access the

seismic via internet.

Hence, the solution allows easy remote connectivity with remote seismic recorders.

Broadband Router

equipped with

Ethernet/RS232ports

GSM / GPRS / EDGE / HSDPA / HSUPA

Modem

Seismic Recorder

equipped withEthernet/RS232

ports

Seismic Recorder

equipped withEthernet/RS232

ports

Seismic Recorder

equipped withEthernet/RS232

ports

Broadband Router

equipped with

Ethernet/RS232ports

GSM / GPRS / EDGE / HSDPA / HSUPA

Modem

Broadband Router

equipped with

Ethernet/RS232ports

GSM / GPRS / EDGE / HSDPA / HSUPA

Modem

Fig. 2 Seismographic network with pure GPRS/APN

The few challenges this technology make unfilled is, in GSM services voice

communication is primary to data transfer so voice is their topmost priority.

Secondly, poor access and unreliability of electricity in Nigeria brings challenges

to the seismic program. Averagely 5 hours per day and the remaining 19 hours, the

population relies on petrol and diesel generators and besides that most remote

Internet/APN

towns are not connected with the national grid. Invariably, basic photovoltaic

system is the last resort to power all the seismic equipment.

Benefits

This technology makes the network independent of the internet and it is more

secured since VPN could be created across the station. Convectional GPRS mobile

device for this solution usually has EDGE and HSDPA capabilities and hence

enhance data transfer.

GPRS mobile devices only use the GSM network when data is transferred and

GSM connection is not dedicated to each user, therefore it can be shared with

many users resulting in efficient use of the network. Billing is not based on time,

but on the amount of data actually transferred.

Direct corporate connectivity is faster, more secured and more easily deployable.

Conclusion

This solution of GPRS/APN is capable of providing high-speed seismic data

transmission, allowing technologies such as EDGE (Enhanced Data rate for GSM

Evolution) which is a specification for data transfer on GSM networks and HSDPA

(High Speed Downlink Packet Access) to be integrated. This would support

seismic data transfer across to the central station for near real time and online

seismic data analysis to generate results like earthquake location of epicentres,

magnitude, coda magnitudes so many more. Hence, special problems of using

VSAT, point-to-point radio connections and DSL technologies are solved with

minimum available resources in Nigeria.

REFERENCES

Jens Havskov and Gerardo Alguacil (2002 ): Instrumentation in Earthquake

Seismology, page 12, 192

Usha Communication Technology (2000): General Packet Radio Service White

Paper

www.scanp.dk : Scan Project Solutions APS, page 1

www.comtechm2m.com/m2m-technology/gprs-tutorial.htm, page 2

www.vpntools.com/vpntools_articles/vpn-tunnel.htm, page 1

www.multenet.com/products/broadbandrouter.html, page 1