Onstyrungas in þǣre Eorðan cīecað hārƿalfas. Þā hārƿalan tectonic plātun synt hrāde ƿeg. þonne hīe bīcuman unstille, þǣr cymð spēd on hīe. Hārƿalfas becumað þonne tectonic plātun sūþen lēase, ƿæs hīe hrāde toweorþað. Se fruma ǣfiscunges hārƿalƿa is hāten hiseophoca oþþe ƿeard. Se eorðstede is se ƿeard on grunde hrǣȳ ofer þǣre hiseohocan.
Folc þe ēaþƿīgað hārƿalfas sint gehātene eorþstirigere. Manege hārƿalfa magon becuman in lytlan ƿīc in nearlicere tid. Se suddenlysa āflīegung þǣre spēde in þām tectonic plātun sęndeð ƿegu spēdan spyrnenda ðe cymað þurh þā Eorðan. Eorþstirigeþræwian smeagaþ þone getācnung, hriþunge, cynn and micelnysse hārƿalƿa.
Ðā ǣfencynn þæs hārƿalƿes mæg becunnan mid sƿīþoscæcemetran. Se sƿīþoscæcemetere fēleð þās sƿīþuncera þǣre eorðan and on ān sƿīþoscæcemetearf hriþað þā sƿīþuncera. Þā strangnes oþþe micelnys þæs hārƿalƿes mæg becunnan be ǣan Rihterscalan. Se Rihterscala wæs funden fram Ċeorl Frauncisc Rihter on 1935. Se scala is getæld 0-10. Ān 2 on þysum scale is a hriþung þe nis eaþe ġerǣccod. And wāccing of wǣrþe 5 (oþþe mā) on wynsumere stōwe. Se micelysta hārƿalƿe ǣfre gemeten hæfde micelnysse 9.5.
Nān ne mæg secgan hwonne hārƿalƿe becymeð. Ac wē cunnun hƿǣr hārƿalfas sīen līclīce to becuman, swā near folcstrǣtum. Ān hārƿalf under sǣ mæg ġescieppan an āƿiġe ƿægn ġehāten tsunāma. Tsunāman magon eac ƿyrcean micel ġesceadƿearge.