Ukuhlaziywa Kokuzamazama Komhlaba
“SESIKUJWAYELE KAKHULU UKUPHILA EMHLABENI OQINILE KANGANGOKUTHI UMA UQALA UKUZAMAZAMA INGQONDO YETHU IYADIDEKA.”—“THE VIOLENT EARTH.”
“UKUZAMAZAMA komhlaba kuphakathi kwamandla emvelo abhubhisayo namakhulu kakhulu,” kuphawula i-World Book Encyclopedia. Leyo nkulumo ayilona ihaba, ngoba amandla okuzamazama komhlaba okunamandla angaba makhulu ngokuphindwe izikhathi ezingu-10 000 kunawebhomu lokuqala le-athomu! Okwesabisa nakakhulu iqiniso lokuthi ukuzamazama komhlaba kungenzeka kunoma yisiphi isimo sezulu, nganoma iyiphi inkathi yonyaka nanganoma yisiphi isikhathi sosuku. Futhi nakuba ososayensi bengase bazi ukuthi ukuzamazama komhlaba okunamandla kungase kwenzeke kuphi, ngeke basho ngokuqondile ukuthi nini.
Ukuzamazama komhlaba kubangelwa ukugudluka kwezingqimba zamadwala ngaphansi komhlaba. Lokhu kuyinto ehlale yenzeka njalo. Ngokuvamile, amaza alokho kunyakaza awamakhulu ngokwanele ukuba azwakale ngaphezu komhlaba, kodwa angathungathwa futhi aqoshwe phansi nge-seismograph.a Ngezinye izikhathi, kuqhephuka idwala elanele futhi ligudluke ngokwanele ukuba lizamazamise umhlaba ngamandla.
Kodwa kungani ungqimba lomhlaba luhlale lunyakaza? “Incazelo ingatholakala ekunyakazeni kwezingqimba, isimo esiye sashintsha umbono wesayensi yoMhlaba,” kusho iNational Earthquake Information Center (NEIC). “Manje siyazi ukuthi kunezingqimba zomhlaba ezingu-7 ezinkulu, ezihlukaniswe zaba yizingqimba ezincane eziningana, zonke ezihlale zinyakaza ngesilinganiso samamilimitha ayishumi kuya kwangu-130 ngonyaka,” kwenezela iNEIC. INEIC ithi ukuzamazama komhlaba okuningi kwenzeka ezindaweni eziyimihosha eyimingcele yezingqimba. Yilapho lapho kunamathuba angamaphesenti angu-90 okuzamazama komhlaba okukhulu khona.
Ubukhulu Negalelo
Amandla okuzamazama komhlaba angase akalwe ngobukhulu noma ngegalelo lako. UCharles Richter wasungula isikali sokulinganisa ubukhulu bokuzamazama komhlaba ngawo-1930. Njengoba lalanda inani leziteshi ze-seismograph, kwasungulwa izilinganiso ezintsha ezisekelwe kwesikaRichter. Ngokwesibonelo, lokho okubizwa ngokuthi isilinganiso sobukhulu bamandla kulinganisa amandla akhishwe emthonjeni wokuzamazama komhlaba.
Yiqiniso, lezi zilinganiso azilembuli njalo izinga lomonakalo owenziwe ukuzamazama komhlaba. Cabangela ukuzamazama komhlaba okwenzeka eBolivia ngo-June 1994, okwakungu-8,2 ngamandla, okuthiwa kwabulala abantu abahlanu kuphela. Kodwa ngo-1976 ukuzamazama komhlaba eTangshan, eChina—okwakungaphansi kuka-8,0 ngamandla—kwabulala amakhulu ezinkulungwane zabantu!
Ngokuphambene nobukhulu, ukukalwa kwegalelo kubonisa umphumela ukuzamazama komhlaba okunawo kubantu, izakhiwo nendawo ezungezile. Lesi isilinganiso esicace kakhudlwana segalelo lokuzamazama komhlaba kubantu. Phela, ukuzamazama ngokwako akuvamile ukubalimaza abantu. Kunalokho, ukudilika kwezindonga, ukuqhuma kwamapayipi egesi noma izintambo zikagesi, izinto eziwayo nokunye, yikho okulimaza abantu nokubabulalayo.
Umgomo wezazi zokuzamazama komhlaba ukukwazi ukunikeza izixwayiso zokuzamazama komhlaba kusengaphambili. Kusungulwa uhlelo lwemishini olubizwa ngokuthi i-Advanced Seismic Research and Monitoring System. Ngokombiko we-CNN, lolu hlelo—kanye nokutholakala ngokushesha kokwaziswa kanye nezinhlelo zama-computer ezinamandla kakhulu—luzosiza izikhulu ukuba “zikwazi cishe ukuthola ngokushesha izindawo lapho umhlaba uzamazame khona kakhulu.” Lokhu kuzokwenza kube lula ngeziphathimandla ukuba zithumele usizo ezindaweni ezithintekile.
Kusobala ukuthi ukuzilungiselela ukuzamazama komhlaba kunganciphisa ukulimala, ukonakala kwempahla—futhi okubaluleke kakhulu—kungasindisa ukuphila. Kodwa ukuzamazama komhlaba kuyaqhubeka kwenzeka. Ngakho umbuzo uwukuthi: Abanye baye basizwa kanjani ukuba babhekane nemiphumela?
[Umbhalo waphansi]
a I-seismograph ithuluzi elikala futhi liqophe ukunyakaza komhlaba lapho uzamazama. Eyokuqala yasungulwa ngo-1890. Namuhla, kuneziteshi ze-seismograph ezingaphezu kuka-4 000 ezisebenzayo emhlabeni wonke.
[Ishadi ekhasini 19]
(Ukuze ubone ukuthi indaba ihlelwe kanjani, bheka encwadini)
Uzamazama Kangaki Umhlaba?
Okuchazayo Isilinganiso sobukhulu IsilinganisoSaminyaka
Yonke
Okukhulu okungu-8 nangaphezulu 1
Okuyinhloko okungu-7 kuya ku-7,9 18
Okunamandla okungu-6 kuya ku-6,9 120
Okuphakathi okungu-5 kuya ku-5,9 800
Okungenamandla okungu-4 kuya ku-4,9 6 200*
Okuncane okungu-3 kuya ku-3,9 49 000*
Okuncane Kakhulu okungu-3,0 Okuyisilinganiso esingu-2
kuya ku-3: cishe
kungu-1 000 ngosuku
Okuyisilinganiso esingu-1
kuya ku-2: cishe
kungu-8 000 ngosuku
* Kuyalinganiselwa.
[Umthombo]
Source: National Earthquake Information Center By permission of USGS/National Earthquake Information Center, USA
[Umthombo Wesithombe ekhasini 19]
Seismogram on pages 4 and 5: Figure courtesy of the Berkeley Seismological Laboratory